Language and Gender in Adolescence Essay

In the perusing, I concur with Penelope Eckert that youths are pioneers of etymological change. As indicated by the World Wide Web, etymological change is a marvel whereby phonetic, morphological, semantic, syntactic, and different highlights of language fluctuate after some time. Young people otherwise called adolescents or youth assume a noteworthy job in breaking down or quickening the sort of etymological framework in a specific spot or network. On the off chance that to be investigated, this can be likened to the solid, dynamic and reliable interest of the adolescent in voicing out their sentiments, getting into social issues and slants, and in making a domain that is reasonable and practically perfect to their age. As I would like to think, there are three reasons which bolster the case that young people are pioneers of semantic change in today’s age. These are peer weight, media and the Internet. Companion Pressure An essential worry for teenagers during immaturity is the issue of ‘fitting in’ and ‘belongingness’. Since puberty is a change period where kids out of nowhere jump to a phase where the person would begin in making a picture of themselves or a self-idea, there is an inclination for them to be lost and befuddled to who and what they should be because of the various alternatives before them. Frequently said than not, youths are more handily influenced instead of grown-ups. It is simpler to show an adolescent that is less developed and still during the time spent knowing his or herself than a grown-up who as of now has a shaped guideline and convictions. For instance, if there is another pattern, let’s state in style or music, an immature would ordinarily be influenced to what is ‘in’ and hit’ to the majority of the individuals around the person in question with the goal that the individual in question might be acknowledged in the circle the individual needed to have a place with. This likewise goes with their selection of words and language. Teenagers will in general talk the route individuals around them talk. They will in general become the people their condition and friends direct them to be so as to be socially acknowledged and important. With regards to selection of words and language, youth can be effectively affected with what vernacular or words to use since in the phase of pubescence fills in as their preparation ground and readiness period of how and who they’ll be later on. In addition, because of companion pressure, teenagers are relegated to gatherings or agreements which can impact another gathering of young people that cause the enlarging of a specific pattern to grow quicker. For instance, in the Philippines there is this specific way or style of talking called the ‘conyo’. Thusly, the individual will in general consolidate their vernacular with American English when talking out in the open or to specific people. Most youth grasped this sort of way since it is what is ‘in’ and acclaimed among young people of their age. Presently, on the off chance that a gathering talks that way, at that point heard by someone else or gathering of people and afterward that specific people receive the way of talking, there is a domino impact of the ‘conyo’ style that changes the semantic framework existing in that specific spot or network. Media and the Internet Media and Internet are two useful assets in etymological change. This can be seen in two different ways: first, media and web as devices in changing and affecting the brains and conduct of the individuals, and second, these devices as utilized by the individuals to change and impact their condition. Since most media and web clients are made out of the youthful populace, those of which have a place with the teen’s age and youthful adulthood, it very well may be presumed that the young people bargain this populace. Presently, how do the media and the Internet fill in as apparatuses in impacting their clients? The media is changing and along any semblance of TV programs that are hit to their watchers, individuals particularly young people are obliging the change. Since media is a day by day part of one’s life, it can undoubtedly impact its watchers on how they ought to be. For instance, most youngsters mirror their preferred craftsmen with their style, selection of stuffs and even with their way of talking and taking care of things. Beside the media, the Internet comprises a lot in phonetic change. The patterns being conveyed by Internet administrations like texting, blogging and person to person communication impacts the way of life of its clients with regards to their etymological style and framework. Texting showed us the short-style of sending messages (I. e. â€Å"Who R U? †, BRB, LOL, and such). Through media and Internet, young people are additionally presented to various styles of language. They are presented to the sort of words they find in pages, papers, magazines and various distributions, and hear in TV and radios or in webcasts that sometime they’ll receive. Then again, these apparatuses are additionally utilized by the individuals to change and impact their condition and co-people. Through these, the young turned out to be progressively engaged while associating with their co-youth and when sharing their standards that influence a lot of individuals. They turned out to be progressively heard, incredible and equipped for changing the phonetic framework they live with. They had the option to assume responsibility for the framework through media, web, and their qualities as youth and populace. To sum up, I accept that teenagers are the pioneers of etymological change. Basically, the interconnectedness of companion weight, media and the web credited to the intensity of the adolescent to be the impetus of progress in their etymological framework because of their own specific manners and styles of managing their condition and in their procedure of finding and knowing them

Forward the Foundation Chapter 20

22 Yugo Amaryl stated, â€Å"Here you are once more, Dors.† â€Å"Sorry, Yugo. I'm disturbing you twice this week. In reality you don't see anybody regularly, do you?† Amaryl stated, â€Å"I don't urge individuals to visit me, no. They will in general interfere with me and break my line of thought. Not you, Dors. You're by and large extraordinary, you and Hari. There will never be a day I don't recollect what both of you have accomplished for me.† Dors waved her hand. â€Å"Forget it, Yugo. You've buckled down for Hari and any silly consideration we accomplished for you has for quite some time been overpaid. How is the Project going? Hari never discusses it-not to me, anyway.† Amaryl's face helped and his entire body appeared to take on an imbuement of life. â€Å"Very well. Great. It's hard to discuss it without arithmetic, however the advancement we've made over the most recent two years is astounding more than in all the time before that. It's just as, after we've been pounding ceaselessly and pounding endlessly, things have at long last started to break loose.† â€Å"I've been hearing that the new conditions turned out to be by Dr. Elar have helped the situation.† â€Å"The achaotic conditions? Indeed. Enormously.† â€Å"And the Electro-Clarifier has been useful, as well. I addressed the lady who planned it.† â€Å"Cinda Monay?† â€Å"Yes. That is the one.† â€Å"A sharp lady. We're lucky to have her.† â€Å"Tell me, Yugo-You work at the Prime Radiant practically constantly, don't you?† â€Å"I'm pretty much continually contemplating it. Yes.† â€Å"And you study it with the Electro-Clarifier.† â€Å"Certainly.† â€Å"Don't you ever consider getting away, Yugo?† Amaryl took a gander at her owlishly, squinting gradually. â€Å"A vacation?† â€Å"Yes. Doubtlessly you've heard the word. You recognize what an excursion is.† â€Å"Why should I take a vacation?† â€Å"Because you appear to be awfully worn out to me.† â€Å"A little, from time to time. Be that as it may, I would prefer not to leave the work.† â€Å"Do you feel more worn out now than you utilized to?† â€Å"A little. I'm getting more established, Dors.† â€Å"You're just forty-nine.† â€Å"That's as yet more established than I've at any point been before.† â€Å"Well, let it go. Let me know, Yugo-just to change the subject. How is Hari getting along at his work? You've been with him so long that nobody might realize him better than you do. Not even I. At any rate, the extent that his work is concerned.† â€Å"He's doing quite well, Dors. I see no adjustment in him. He despite everything has the snappiest and most splendid cerebrum in the spot. Age is having no impact on him-at any rate, not all that far.† â€Å"That's acceptable to hear. I'm worried about the possibility that that his own assessment of himself isn't as high as yours may be. He's not taking his age well. We made some troublesome memories getting him to commend his ongoing birthday. Is it true that you were at the celebrations, coincidentally? I didn't see you.† â€Å"I went to part of the time. In any case, you know, gatherings of that sort are not the kind of thing I feel comfortable with.† â€Å"Do you think Hari is wearing out? I'm not alluding to his psychological splendor. I'm alluding to his physical limits. As you would see it, is he becoming tired-too tired to even consider bearing up under his responsibilities?† Amaryl looked surprised. â€Å"I never gave it any idea. I can't envision him developing tired.† â€Å"He might be, regardless. I think he has the motivation, from time to time, to surrender his post and hand the errand over to some more youthful man.† Amaryl sat back in his seat and put down the realistic pointer he had been tinkering with since the time Dors had entered. â€Å"What! That is strange! Impossible!† â€Å"Are you sure?† â€Å"Absolutely. He positively wouldn't think about something like this without examining it with me. Also, he hasn't.† â€Å"Be sensible, Yugo. Hari is depleted. He does whatever it takes not to show it, yet he is. Imagine a scenario in which he decides to resign. What might happen to the Project? What might happen to psychohistory?† Amaryl's eyes limited. â€Å"Are you kidding, Dors?† â€Å"No. I'm simply attempting to investigate the future.† â€Å"Surely, if Hari resigns, I prevail to the post. He and I ran the Project for quite a long time before any other individual went along with us. He and I. Nobody else. Aside from him, nobody knows the Project as I do. I'm astonished you don't underestimate my progression, Dors.† Dors stated, â€Å"There's no doubt in my psyche or in any other individual's that you are the consistent replacement, however would you like to be? You may have a deep understanding of psychohistory, yet would you like to dedicate yourself completely to the legislative issues and complexities of an enormous Project and surrender a lot of your work so as to do as such? All things considered it's attempting to keep everything moving easily that has been wearing Hari down. Would you be able to take on that piece of the job?† â€Å"Yes, I can and it's not something I mean to examine. Look here, Dors. Did you come here to break the news that Hari expects to ease me out?† Dors stated, â€Å"Certainly not! How might you believe that of Hari! Have you at any point realized him to turn on a friend?† â€Å"Very well, at that point. How about we drop the subject. Truly, Dors, if its all the same to you, there are things I should do.† Abruptly he got some distance from her and twisted around his work again. â€Å"Of course. I didn't intend to take up this a lot of your time.† Dors left, scowling. 23 Raych stated, â€Å"Come in, Mom. There's no sign of danger. I've sent Manella and Wanda off somewhere.† Dors entered, watched both ways out of sheer propensity, and plunked down in the closest seat. â€Å"Thanks,† said Dors. For some time she just stayed there, looking as though the heaviness of the Empire were on her shoulders. Raych paused, at that point stated, â€Å"I never got an opportunity to get some information about your wild stumble into the Palace grounds. It isn't each person who has a mother who can do that.† â€Å"We're not discussing that, Raych.† â€Å"Well at that point, let me know. **You're not one for parting with anything by outward appearances, however you look sorta down. For what reason is that?† â€Å"Because I feel, as you state, sorta down. Truth be told, I'm feeling awful on the grounds that I have frightfully significant things at the forefront of my thoughts and there's no utilization conversing with your dad about it. He's the most brilliant man on the planet, however he's exceptionally difficult to deal with. There's zero chance that he'd look into the emotional. He excuses everything as my unreasonable feelings of trepidation for his life-and my resulting endeavors to ensure him.† â€Å"Come on, Mom, you do appear to have unreasonable apprehensions where Dad's concerned. On the off chance that you have something sensational at the top of the priority list, it's most likely all wrong.† â€Å"Thank you. You sound simply as he does and you leave me baffled. Completely frustrated.† â€Å"Well at that point, unburden yourself, Mom. Mention to me what's at the forefront of your thoughts. From the beginning.† â€Å"It begins with Wanda's dream.† â€Å"Wanda's fantasy! Mother! Perhaps you would be advised to stop at the present time. I realize that Dad won't have any desire to tune in on the off chance that you start that way. That is to say, please. A little child has a fantasy and you overplay it. That is ridiculous.† â€Å"I don't think it was a fantasy, Raych. I think what she thought was a fantasy were two genuine individuals, discussing what she thought concerned the demise of her grandfather.† â€Å"That's a wild supposition on your part. What conceivable possibility does this have of being true?† â€Å"Just assume it is valid. The one expression that stayed with her was ‘lemonade passing.' Why would it be advisable for her to dream that? Almost certainly, she heard that and mutilated the words she heard-in which case, what were the undistorted words?† â€Å"I can't tell you,† said Raych, his voice wary. Dors didn't neglect to get that. â€Å"You think this is only my wiped out creation. In any case, in the event that I happen to be correct, I may be toward the beginning of unwinding a scheme against Hari directly here in the Project.† â€Å"Are there tricks in the Project? That sounds as difficult to me as discovering importance in a dream.† â€Å"Every huge venture is filled with infuriates, erosions, jealousies of all sorts.† â€Å"Sure. Sure. We're talking awful words and faces and nose thumbing and gossipy. That is nothing at all like talking trick. Dislike looking at slaughtering Dad.† â€Å"It's only a distinction in degree. A little distinction maybe.† â€Å"You'll never cause Dad to accept that. So far as that is concerned, you'll never cause me to accept that.† Raych strolled hurriedly over the room and back again, â€Å"And you've been attempting to ease out this supposed scheme, have you?† Dors gestured. â€Å"And you've failed.† Dors gestured. â€Å"Doesn't it happen to you that you've fizzled on the grounds that there is no trick, Mom?† Dors shook her head. â€Å"I've bombed up until this point, yet that doesn't shake my conviction that one exists. I have that feeling.† Raych snickered. â€Å"You sound normal, Mom. I would hope for something else from you than ‘I have that feeling.†Ã¢â‚¬Ëœ â€Å"There is one expression that I think can be misshaped into ‘lemonade.' That's ‘layman-supported.' â€Å" â€Å"Laymanayded? What's that?† â€Å"Layman-helped. Two words. A layman is the thing that the mathematicians at the Project call nonmathematicians.† â€Å"Well?† â€Å"Suppose,† contributed Dors solidly, â€Å"someone talked about ‘layman-supported demise,' implying that some way could be found to execute Hari in which at least one nonmathematicians would assume a basic job. Might that not have sounded to Wanda like ‘lemonade passing,' taking into account that she had never heard the expression ‘layman-supported' anything else than you, yet that she was remarkably partial to lemonade?† â€Å"Are you attempting to disclose to me that there were individuals in Dad's private office, out of every other place on earth. What number of individuals, by the way?†

Trifles and symbols Essay Example For Students

Wastes of time and images Essay In the play titled Trifles, by Susan Glaspell, Minnie Foster Wright is being blamed for killing her significant other, John. In this creation, Mrs. Wright is reliably referenced, and in spite of the fact that she isn't seen, she is entirely unmistakable. There are significant images in this play means Mrs. Wright and her reality as it used to be and as it right now exists to be. Especially the canary, this represents Mrs. Wrights since quite a while ago overlooked past. Also, the birdcage, this represents her life as it at present exists. Absolutely the blanket is an image, which is a significant piece of information on how Mr. Wright was executed. Also, the recliner, this represents her life as it has reduced all through the length of her most as of late endure years. Finally, however not least, the compartments of cherry jam that appear to be an image of the glow and sympathy that she presently can't seem to find in her life. All of these represents and describes Mrs. Wrights character and her reality in the play. The canary and the birdcage are representative to Mrs. Wrights life in the manner that the winged animal speaks to her, and the enclosure speaks to her life and the manner in which she was made to live. Mrs. We will compose a custom exposition on Trifles and images explicitly for you for just $16.38 $13.9/page Request now Sound thinks about the canary that she and Mrs. Subsides find to Mrs. Wright, when Mrs. Sound alludes to Mrs. Wright as sort of like a feathered creature herselfreal sweet and pretty, yet sort of bashful andfluttery. Minnie Foster was a particularly unexpected lady in comparison to Minnie Foster Wright, which was, obviously before she and John were hitched. She dressed urgently in eye-discovering apparel, and was one of the town young ladies that sang in the ensemble. While the canary was unimaginably energetic and sang wonderfully did as well, Mrs. Encourage. John Wright was dreadfully oppressive towards Mrs. Wright, in the implies that he expected her to carry on with her life practically identical to a confined flying creature. He got her opportunity from the outside world, consequently, clarifies why she perceived herself in the feathered creature. This clarifies for the thinking of their home being far hindered into the forested areas and having no telephone utility. She wandered out, just when she was permitted, and expecting that John additionally didn't permit her to have companions, this prompted the slaughtering of the canary. The blanket is one significant piece of information concerning how Minnie executed her better half. The ladies were attempting to make sense of in the event that she would sew or not the blanket. All things considered, Mr. Wright was choked in an unusual way, exactly how the bunch was wrecked in red string. The men dismissed it butt Mrs. Solidness and Mrs. Diminishes recognized what had occurred. Mrs. Wright is alluded to when Mrs. Sound discusses her by utilizing her family name, when saying I wish youd seen Minnie Foster when she wore a white dress with blue strips and stood up there in the ensemble and sang. The old armchair represents Mrs. Wright as she has permitted herself to devalue, similarly as the armchair has deteriorated. The seat hang to the other side, Mrs. Sound expressed that the seat was nothing similar to she alluded, to the way that Mrs. Wright has likewise changed since she recalled. This exhibits Minnie Foster, who was once something to take a gander at, formed into the torn down looking Minnie Wright. It was a nitty gritty assignment that necessary long periods of troublesome work in the high temperature of the kitchen. She took a lot of pride in her creation since she connected herself with the jelly, as this was the single thing in her life that she really treasured. To occupy the time in the melancholy family unit that had become her jail, she canned fruits that would give her a guarantee of something to anticipate neglected, fresh winter. At the point when the sub zero cold temperatures discovered Minnie in a prison cell, faraway from her kitchen, and her jam, she wound up worried that the containers would freeze up and break. At the point when the chilliness situated it into the house, the containers broke and created a clingy mess, practically identical to the mayhem that she had now put her life in. Minnie had a minor measure of .

Postal Contract and Law Essay Example | Topics and Well Written Essays - 2000 words

Postal Contract and Law - Essay Example P. 71). As indicated by Lord Denning, there is huge contrast between the standard of prompt correspondence and the postal guideline. The offeror must get acknowledgment of his proposal for the agreement to be finished. In quick method of correspondence of acknowledgment, the spot of arrangement of the agreement is the spot at which the acknowledgment is gotten by the offeror (Davies, 2005. P. 158). In the current day corporate world, correspondence is predominantly by methods for teleprinter, copy or electronic mail. Electronic correspondence is as yet encircled by discussion concerning its lawfulness. The trend setting innovation used in such correspondence modes empowers simple transmission of interchanges. In this manner, electronic correspondence can be sent whenever to a goal, much in the wake of working hours. This brings up the issue about the purpose of time when the electronic correspondence had been legitimately efficacious. The postal guideline doesn't matter to prompt types of correspondence (Brinkibon Ltd v Stahag Stahl und Stahlwarenhandels GmbH). This was the decision in Entores Ltd v Miles Far East Corp (Entores Ltd v Miles Far East Corp). Electronic mail is transmitted a lot quicker than the mail sent by post. Be that as it may, electronic mail can't be considered to be immediate correspondence between the gatherings. The purpose behind this is the sending and receipt of electronic mail may take anything between a couple of hours to a few days. Consequently, it doesn't establish momentary correspondence. Thus, the postal guideline applies to electronic mail. An offer is esteemed to be appropriately conveyed in momentary correspondence, if the recipient has notice of the offer. In non †immediate methods of correspondence, the offer is conveyed through letters, wires or different techniques. Such correspondence must be dispatched to the recipient and got by the

Compare and Contrast Assignment Wal-Mart’s Strategies - 1100 Words

Compare and Contrast Assignment: Wal-Mart’s Strategies (Article Sample) Content: Name:Tutor:Course:Due date:Compare and ContrastThe book They Say, I say, contains two critics who share contrasting notions on Wal-Marts strategies towards their employees. The manner in which Wal-Mart treats their workforce is wholly unjustified. Through Wal-Marts anti-union protests, minimal wages as well as women discrimination, Wal-Mart as an institution ought to re-examine their policies thus ensuring better living standards for their workers. The fact that Wal-Mart needs to aim at bettering employees lives, other people think otherwise. For example, Sebastian Mallaby who works at Washington Post as a columnist gives a thought that Wal-Mart should mainly focus on improving peoples lives especially the less fortunate in society. Indeed, Wal-Mart should ensure that workers needs are taken catered for and provide minimal prices for poor families. On the other part, Karen Olsson attached to Texas Monthly as a senior editor also iterates that Wal-Mart should give empl oyee livelihood the first priority. Irrational strategies of Wal-Mart need to be changed so as to improve living standards of all their workers.Wal-Mart would rather create affordable products for their clients instead of high-class benefits for their workers. Sebastian Mallaby trusts that Wal-Mart establishment is enormously beneficial to the poor people. Mallaby goes farther to iterate that Wal-Marts aid of $200 billion-plus offers poverty relief for clients through their everyday minimal prices (Mallaby 620). As Wal-Mart stakeholders embark to give poverty relief for customers, they forget to initiate the so-called poverty relief to their workers. As a matter of fact, Wal-Mart workers barely receive $18,000 as annual salary when compared to $35,000 average annual returns for Wal-Mart customer (Mallaby 624). It is discouraging that even Wal-Marts headquarters fail to notice that they arent offering relief for their immediate employees. Sebastian Mallaby claims that failure of Wal- Mart to start up new branches, Americans who are poor will be chief amidst the casualties. Instead of poor and less fortunate Americans being casualties, Wal-Mart employees are casualties. Low prices blind most Americans neglecting the fact that employees are indeed suffering from the norm. Unequal balance exists between client needs and those of employees (Olsson 609). A mechanism should be derived by Wal-Mart ensuring that both parties obtain the deserved benefits. While Sebastian Mallaby had strong notions towards Wal-Mart Company, Karen Olsson portrays conflicting views from him.Wal-Marts irrational minimal wages trigger employees to experience a difficult way of life. With families to cater for basic needs like food, clothing and shelter, workers struggle in making the ends meet for a decent living. In a bid to altering for budget cuts, Wal-Mart force employees to work for extra hours without pay for minimal wages during the normal working time (Olsson 607). Working overtime re quires some compensation or rather appreciation for extra effort put at work. Conversely, Wal-Mart takes advantage over their endurance. Employee treatment in the company is not only unjust but also immoral. An employee, a lady, believes that her working tenure will come to a stop after attaining 90 years (Olsson 615). Workers at the establishment keep worrying about their future retirement plan instead of being supplied with adequate funds to keep them going. To safeguard future generations from facing the same manner of cruelty as workers, it is vital for Wal-Mart to amend their policies. Wal-Mart being among the top employers, low pay would negatively impact the prospect of working in America shunning workers from performing their duties wholeheartedly (Olsson 608).Wal-Mart ought to take interests of employees at heart treating them as their number one priority. Different studies have come to a conclusion that in a span of a decade, almost 2 million people globally are willing to work at Wal-Mart. Therefore, being among the dominant employers worldwide, the establishment has to alter their ways ensuring better tomorrow for both current and future workers. For sure, Wal-Mart has avoided their obligation of caring for their workers.Wal-Marts low wages also affect employees in seeking for sufficient and efficient health care. Most establishments provide medical schemes for their workers. Upon instances of injury while at work, employees are compensated fully to affirm worker satisfaction. Wal-Marts medical plan is too costly at approximately $2,844. The huge sum of money becomes a challenge for Wal-Marts workers to raise for a health plan with $18,000 annual salary. Workers are therefore forced to make critical decisions of neglecting a health plan in order to survive in the challenging economy. Despite the fact that Wal-Mart is listed top on the Fortune 500, their workers fight to acquire health covers for their families more so kids. Wal-Mart needs to realiz e that their minimal wages affect both workers and their families. Low wages drives living conditions for both workers and their families to be extremely challenging (Karen Olsson 610).Organizations provide smooth working conditions for realization of maximum returns. In most instances, this is nor...

Plant-pollinator interactions - Free Essay Example

Abstract Very little work has been done on the evolution of floral colour diversity, outside of Europe and the Middle East. In particular, we know almost nothing about the evolution of the Australian flora in the context of hymenopteran visual systems. Such a study is likely to be important due to the geologically long isolation of the Australian flora and the high proportion of endemic plant species. The aims of this study were to investigate the colour of Australian native flowers in the context of hymenopteran visual systems, the innate colour preferences of Australian native bees (Trigona carbonaria), and the interactions between native bees and a food deceptive orchid (Caladenia carnea). Firstly, I found that the discrimination thresholds of hymenopterans match up with floral colour diversity and that hymenopterans appear to have been a major contributor to flower colour evolution in Australia. Secondly, I found that Trigona carbonaria has innate preferences for wavelengths of 422, 437 and 530 nm. Thirdly, I found that bees were able to habituate to orchid flowers based on colour, thus potentially explaining the colour polymorphism of Caladenia carnea. Together, my study suggests that the evolution of the Australian flora has been influenced by hymenopterans. 1. Introduction Plant-pollinator interactions The mutual interactions between pollinators and plants have been suspected in driving angiosperm radiation and diversification in the past (Regal 1977; Crepet 1984; McPeek 1996). The obvious mutual benefit is that pollinators depend on the pollen and/or nectar of flowering plants for food and, in return, partake in the incidental transfer of pollen necessary for plant reproduction (Faegri and van der Pijl 1978; Harder, Williams et al. 2001). Worldwide, it is estimated that more than 67% of angiosperm plants rely on pollination by insects (Tepedino 1979). Hence, pollinators play a critical role in the persistence and survival of flowering plants, which are of high value to the human food chain (Kearns and Inouye 1997; Klein, Vaissiere et al. 2007). Flower colour signals and sensory exploitation Colour is the result of the visible light being absorbed or reflected off objects and then processed by the eye and brain of an animal (Le Grand 1968). Light is part of the electromagnetic spectrum, and can be quantified by the wavelength of different photons of energy (Bueche 1986). The wavelengths reflected off the object are perceived by a visual system as the objects colour. For example, light that appears blue to a human observer can be described by a dominant wavelength of 400nm, whilst light that appears red is 700nm. Ultraviolet light falls between 300-400nm and can be seen by bees, but not humans. Flower colours have been influenced by the sensory receptors of insects, including their colour vision, which is different to human vision. Humans have a red, blue and green receptor (Chittka and Wells 2004). In contrast insects have a UV, green and blue receptor (Chittka and Wells 2004). As human vision is very different to a hymenopterans colour visual system, one cannot discuss a bees colour perception according to human colour terms such as red or blue. Therefore, this thesis will discuss colours according to wavelength. Colour is one of the most important floral signals plants use to communicate information to insect pollinators (Giurfa, Vorobyev et al. 1996; Dyer, Spaethe et al. 2008). Although it is known that pollinators select flowers based on morphology, nectar availability, size, and odour (Giurfa, Nez et al. 1994; Kunze and Gumbert 2001; Spaethe, Tautz et al. 2001; Whitney and Glover 2007), colour is known to play a critical role in enabling pollinators to detect and discriminate target flowers from a biologically important distance of up to 50 cm (Giurfa, Vorobyev et al. 1996; Dyer, Spaethe et al. 2008). Our understanding of the evolution of colour vision in insects has advanced considerably in recent years. In the past, studies of colour perception were limited due to little information on the colour visual system of insects (Frisch 1914; Daumer 1956). It is now possible to evaluate how flower visual signals appear to the visual system of hymenopteran pollinators, using spectrophotometer and colorimetry techniques, which allows quantitative evaluations of how complex colour information is perceived by insect pollinators (Chittka 1992) (fig. 1). Previous research has revealed that colour discrimination in hymenopterans is phylogenetically ancient, with different hymenopterans sharing similar colour perception (Helversen 1972; Chittka and Menzel 1992). Importantly, colour discrimination in the hymenoptera is known to predate the evolution of floral colour diversity (Chittka 1996). Here, recent research has revealed remarkable convergence in the evolution and distribution of floral colours in different parts of the world. Specifically, in a seminal paper, Chittka (1996) showed that flowering plants in both Europe and the Middle East have adapted their colour signals to the visual systems of bees, with flower colours in these regions closely matched to the visual receptors of hymenopterans (Chittka 1996). However, outside of Europe and the Middle East, very little work has been done on the evolution of floral colour diversity. In particular, we know almost nothing about the evolution of the Australian flora in the context of hy menopteran visual systems. This is an important question to investigate due to the long isolation of the Australian flora and the high proportion of endemic plant species. I hypothesise that the Australian floral coloration will closely match the discrimination thresholds of hymenopterans as recent evidence suggests that insect pollinators supported the early spread of flowering plants (Hu, Dilcher et al. 2008). Innate colour preferences of bees Charles Darwin was the first to state that innate preferences could allow an inexperienced pollinator to find a food source (Darwin 1877). Pollinators may use certain traits of flowers such as morphology, scent, temperature and colour to locate food (Heinrich 1979; Menzel 1985; Dyer, Whitney et al. 2006; Raine, Ings et al. 2006). Previous studies evaluating innate colour preferences have tended to focus on two species: the European honey bee (Apis mellifera) and bumblebee (Bombus terrestris). By contrast, no studies have looked at the innate colour preferences of Australian bees and how this affects their choices for flowers. We know that European bumblebees and honeybees show strong preferences for violet and blue (400-420nm) throughout their geographic range (Chittka, Ings et al. 2004) ,which interestingly correlates with the most profitable food sources (Lunau and Maier 1995; Chittka and Raine 2006). These preferences are likely to have had an impact on the relative success of dif ferent flower colours in regions where these bees are dominant pollinators (Chittka and Wells 2004). Consequently, information on the innate preferences of Australian bees will be important to understand hymenopteran plant interactions in the Australian context. Pollinator learning and food deceptive orchids Most plants reward their pollinators with nectar or pollen. However, some species do not offer floral rewards and, instead, employ a range of deceptive techniques to trick insects into performing the task of pollination. Deceptive pollination strategies are particularly well known and widespread among orchids (Jerskov, Johnson et al. 2006). For instance, approximately 400 orchid species are known to achieve pollination through sexual deceit, luring unsuspecting male insects to the flower through olfactory, visual and tactile mimicry of potential mates. More common are food deceptive orchids which are believed to number as many as 6,000 species (one-third of orchids) (Jerskov, Johnson et al. 2009). Food mimicking orchids employ bright colours to falsely advertise the presence of a reward to attract naive pollinators (Ackerman 1986; Nilsson 1992; Jerskov, Johnson et al. 2006). The common occurrence of food deception in orchids suggests that this form of pollination by deception is an e xtremely successful evolutionary strategy (Cozzolino and Widmer 2005). Visits by pollinators to deceptive plants are influenced by pollinator learning. In the case of sexual deception, previous research shows that insects quickly learn unrewarding flower decoys and avoid them. For example, male insects learn to avoid areas containing sexually deceptive orchids (Peakall 1990; Wong and Schiestl 2002). However, whether insects can learn to avoid food deceptive orchids remains to be investigated. In addition, high levels of variability in floral traits, particularly flower colour and floral scent, may interrupt the associative learning of insects by preventing their ability to become familiar with deceptive flowers (Schiestl 2005). Indeed, variation in colour, shape and fragrance is evident in non-model food-deceptive orchids (Moya and Ackerman 1993; Aragn and Ackerman 2004; Salzmann, Nardella et al. 2007). However, previous studies have only looked at pollinator preference for colour morphs (Koivisto, Vallius et al. 2002), rather than assessing if variable flower colour slows down the ability of naive pollinators to learn unrewarding flower decoys. Furthermore, there is a need to incorporate a combination of colour vision science and behavioural ecology to understand how a bee perceives the orchid flowers, as bees have a different visual system to humans. Although humans cannot see ultra-violet light, UV sensitivity is common in some animals (Tove 1995). UV sensitivity has been found in insects, birds, fish and reptiles (Marshall, Jones et al. 1996; Neumeyer and Kitschmann 1998; Cuthill, Partridge et al. 2000; Briscoe and Chittka 2001). Studies on UV vision in an ecological context have mainly focused on species specific signalling and mate choice (Bennett, Cuthill et al. 1996; Bennett, Cuthill et al. 1997; Pearn 2001; Cummings, Garc et al. 2006). However, few studies have looked at the role of UV signals in attracting bees to orchids. Previous studies have shown that the presence of UV reflecting crab spiders attracts honeybees to daisies (Heiling, Herberstein et al. 2003). In a similar study, Australian native bees (Austroplebia australis) were attracted but did not land on flowers with UV reflecting crab spiders (Heiling and Herberstein 2004). However, the role of UV signals in orchids is not well studied. In particular, it is not known if the UV signal is important in attracting naive bees to food deceptive orchids. Thus, it will be useful to know if UV signals might also serve to lure naive pollinators to deceptive flowers to understand deceptive pollination. Aims This project will investigate Australian flower colour diversity in the context of hymenopteran visual systems, the innate colour preferences of Australian native bees (Trigona carbonaria) and their interactions with a food deceptive orchid (Caladenia carnea). This study aims to address the following questions: 1. Is there a link between hymenopteran vision and Australian floral coloration? 2. Does an Australian native bee (Trigona carbonaria) have innate colour preferences? 3. Does a food deceptive orchid (Caladenia carnea) exploit the innate colour preferences of Trigona carbonar 2. Methods Part 1. Is there a link between hymenopteran vision and Australian floral coloration? Flower collection and spectral reflectance functions of Australian native plant flowers Australian native flowers were collected from Maranoa Gardens, Balwyn (melway ref 46 F7). Maranoa Gardens was chosen due to the diverse collection of species from all over Australia. Flowers were collected once a month, from May to January. A colour photograph was taken of the flower for identification. I also took a UV photograph for all flowers, using a digital UV camera [Fuji Finepix Pro S3 UVIR modified CCD for UV imaging] with calibrated UV-vis grey scales (Dyer, Muir et al. 2004). As UV rays are invisible to the human eye (Menzel and Blakers 1976; Dyer 2001), this photo enabled any UV reflectance areas of the flower to be measured by the spectrophotometer (Indsto, Weston et al. 2006). The spectral reflection functions of flowers were calculated from 300 to 700 nm using a spectrophotometer(S2000) with a PX-2 pulsed xenon light source attached to a PC running SpectraSuite software (Ocean Optics Inc., Dunedin, FL, USA). The spectrophotometer was used to quantify the colour of the flower as wavelength. The white standard was a freshly pressed pellet of dry BaSO4, used to calibrate the spectrophotometer. A minimum of three flowers from each plant were used for each spectral analysis. I evaluated a sample of 111 spectral measurements from Australian flowering plants, encompassing a representative variety of plant families (fig. 2). Correlations between spectral reflectance functions of different plant flowers and trichomatic vision of the honeybees To understand if there is a link between hymenopteran vision and Australian native flowers, I used the methodology used by Chittka and Menzel (1992). In that study, Chittka and Menzel looked for correlations between flower spectra sharp steps of different plant flowers and trichomatic vision of the honeybees. Sharp steps are a rapid change in the spectra wavelength (Chittka and Menzel 1992) (see fig. 3 for an example of a sharp step). These steps cross over different receptors, thereby producing vivid colours that stand out from the background. Furthermore, a colour signal will be more distinguishable to a pollinator if the sharp steps match up with the overlap of receptors in a visual system. Thus, the main feature of a flower wavelength is a sharp step. For this study, I defined a sharp step as a change of greater than 20 % reflectance in less than 50 nm of the bee visual spectrum. The midpoint of the slope was determined by eyesight as described by Chittka and Menzel (1992), as th e nature of curves varied with each flower. The absolute numbers of sharp steps within each flower spectra were counted. The frequencies are shown in fig. 4b. As hybrid plants are artificially selected by humans, hybrid flowers were not included in the analyses. Generating a Hexagon colour space To evaluate how flower colours are seen by bees, I plotted the flower colour positions in a colour hexagon space. A colour space is a numerical representation of an insects colour perception that is suitable for a wide range of hymenopteran species (Chittka 1992). In a colour space, the distances between locations of a two colour objects link with the insects capacity to differentiate those colours. To make the colour space, the spectral reflectance of the colour objects were required, as well as the receptor sensitivities of the insect. For Trigona carbonaria, the exact photoreceptors are currently unknown, but hymenopteran trichromatic vision is very similar between species as the colour photoreceptors are phylogenetically ancient (Chittka 1996). Thus, it is possible to model hymenopteran vision with a vitamin A1 visual template (Stavenga, Smits et al. 1993) as described by Dyer (1999). I then predicted how the brain processed these colour signals by using the average reflectance f rom each flower, and calculating the photoreceptor excitation (E) values, according to the UV, blue and green receptor sensitivities (Briscoe and Chittka 2001) using the methods explained by Chittka (1992). The UV, blue and green E-values of flower spectra were used as coordinates and plotted in a colour space (Chittka 1992). The colour difference as perceived by a bee was calculated by the Euclidean distance between two objects locations in the colour hexagon space (Chittka 1992). Modelling the distributions of Australian flower colours according to bees perception I analysed the most frequent flower colour according to a bees colour perception using the methods of Chittka, Shmida et al. (1994). I plotted the Australian flower colours in a colour space (Fig 5a). A colour space is a graphical representation of a bees colour perception. A radial grid of 10 degree sectors was placed over the distribution of colour loci and the number of floral colour loci within each sector was counted(fig. 5b). Part 2. Does an Australian native bee (Trigona carbonaria) have innate colour preferences? Insect model and housing Trigona carbonaria is an Australian native stingless bee that lives in colonies of 4000-10000 individuals (Heard 1988). In the wild, stingless bees live in hollows inside trees (Dollin, Dollin et al. 1997). Trigona carbonaria has a similar social structure to the honeybee (Wille 1983). They are common to North Eastern Australia and are a potentially important pollinator for several major commercial crops (Heard 1999). A research colony (ca. 4000 adults and 800 foraging individuals) of T. carbonaria was propagated for the experiments by Dr Tim Heard (CSIRO Entomology, 120 Meiers Rd, Indooroopilly 4068, Australia) as described in the paper by Heard (1988). Bees were maintained in laboratory conditions so that no previous contact with flowers had been made. For this study, a colony was placed in a pine nest box (27.5 x 20 x 31 cm; LWH) and connected to the foraging arena by a 16 cm plexiglass tube, containing individual shutters to control bee movements. All laboratory experiments were conducted in a Controlled Temperature Laboratory (CTL) at Monash University, Clayton, School of Biological Sciences (CTL room G12C dimensions 3 x 5m), during the months of July 2009- January 2010. Relative humidity (RH) was set to 30%, and the temperature was set to 27 C (SPER-Scientific Hygrometer, Arizona, USA), as this set up approximately matches conditions in Queensland for insect pollinators (Heard and Hendrikz 1993). Illumination (10/14 hr day/night) was provided by four Phillips Master TLS HE slimline 28W/865 UV+ daylight fluorescent tubes (Holland) with specially fitted high frequency (1200Hz) ATEC Jupiter EGF PMD2x14-35 electronic dimmable ballasts which closely matches daylight conditions for trichromatic hymenoptera (Dyer and Chittka 2004). The flight arena (1.2 x 0.6 x 0.5m; LWH) was made of a coated steel frame with laminated white wooden side panels. The arena floor was painted foliage green, and the arena lid was covered with UV transparent plexiglass. Experiments we re conducted from 1pm-3pm to control for time of day, as this is when bees are most active (Heard and Hendrikz 1993). Pre-training Bees were habituated to the flight arena for seven days. Naive foragers (i.e. bees that had never encountered real or artificial flowers) were initially pre-trained to forage in the flight arena on three rewarding aluminium sanded disks (25 mm in diameter), with a 10-l droplet of 15% (w/w) sucrose solution placed in the centre. The disks were placed on vertical plastic cylinders (diameter = 25 mm, height = 100 mm), to raise them above the floor of the flight arena so that bees learnt to fly to the disks. Pre-training allows bees to become habituated to visiting artificial flowers for further experiments. The aluminium sanded disks were chosen as neutral stimuli because they have an even spectral reflectance curve in the spectral visual range of the bees, fig. 6. The sucrose solution reward on these training disks was refilled using a pipette after it was consumed by foraging bees. The spatial positions of these training disks were pseudo randomised, so that bees would not learn to as sociate particular locations with reward. Bees were allowed a minimum of two hours to forage on the pre-training disks before data collection Innate colour preference testing To test the innate colour preferences of naive bees, I performed simultaneous choice experiments with flower-naive bees using artificial flowers that simulated the floral colours of natural flowers. The aluminum rewarding disks were replaced by the ten unrewarding, coloured artificial disks in the original flight arena. Artificial flower stimuli were cut in a circle (70 mm diameter) from standardized colour papers of the HKS-N-series (Hostmann-Steinberg K+E Druckfarben, H. Schmincke Co., Germany). In each experiment the same set of ten test colours (1N pale yellow, 3N saturated yellow, 21N light pink, 32N pink, 33N purple, 50N blue, 68N green, 82N brown, 92N grey, back of 92N white) were used. These colours were chosen as they have been used in innate colour experiments with other hymenopterans (Giurfa, Nez et al. 1995; Kelber 1997; Gumbert 2000), and the colours are also widely used in other bee colour experiments (Giurfa, Vorobyev et al. 1996). The coloured paper disks w ere placed on vertical plastic cylinders (diameter = 15 mm; height = 50 mm), to raise them above the floor of the flight arena. The gate was shut in the arena to ensure the bees used in each trial were separated from the next trial. The number of landings and approaches to the stimuli were recorded for one hour. Approximately 200 bees were used for each trial. The spatial positions of the artificial flowers were pseudo randomised in a counter balance fashion every 15 minutes. After each trial, the colour disks were aired and wiped with a paper tissue to remove possible scent marks, which are known to affect experiments with honeybees (Schmitt and Bertsch 1990; Giurfa and Nez 1992). I conducted each subsequent trial after removing the used bees from the system, to ensure that the bees in the next trial were replaced with naive foragers. It is known that perception of colour can be influenced by background colour (Lunau, Wacht et al. 1996). Therefore, I also tested colour choices on other background colours of grey and black. The results are qualitatively similar (fig. 8b), so only data from the biologically relevant green background was used for subsequent analysis. Analysis of colour stimuli As bees see colours differently to humans, I quantified stimuli according to five parameters: wavelength, brightness, purity (saturation), chromatic contrast to the background and green receptor contrast. Dominant wavelength was calculated by tracing a line from the centre of the colour hexagon through the stimulus location to the corresponding spectrum locus wavelength (Wyszecki and Stiles 1982). Brightness was measured as the sum of excitation values of the UV, blue and green receptors (Spaethe, Tautz et al. 2001). Spectral purity of the stimulus was calculated by the percentage distance of the stimulus in relation to the end of the spectrum locus (Chittka and Wells 2004). Chromatic contrast was calculated as the distance of a colour stimulus from the centre of the colour hexagon relative to the background. Chromatic contrast is important as perception can be affected by background colour (Lunau, Wacht et al. 1996). Green receptor contrast was measured as the green receptor excitat ion from a stimulus relative to the background (Giurfa, Nez et al. 1995). This contrast is relevant as green receptors and green contrast are known to affect motion in bees (Srinivasan, Lehrer et al. 1987). Statistical analyses The impact of wavelength on number of landings by Trigona carbonaria was investigated using a single factor analysis of variance (ANOVA) and a post hoc Tukeys HSD test (=0.05) (Quinn and Keough 2002) using the number of landings as the dependent variable and wavelength of stimuli as the independent variable. Brightness, purity (saturation), chromatic contrast to the background and green receptor contrast of stimuli were analysed using the Spearmans rank correlation test against choices. Statistical analyses were conducted using R statistical and graphical environment (R Development Core Team, 2007). Statistical significance was set to P0.05. Part 3. Does a food deceptive orchid (Caladenia carnea) exploit the innate colour preferences of Trigona carbonaria? Plant model Caladenia carnea is a widespread species, common to eastern Australia. The orchid is highly variable in colour, ranging from pink to white. It is pollinated by Australian native bees of the Trigona species (Adams and Lawson 1993).With bright colours and fragrance, this orchid achieves pollination by food mimicry (Adams and Lawson 1993). Thus, due to the colour variation of the orchid, C. carnea is an excellent model with which to examine floral exploitation of potential pollinators. Caladenia carnea flowers were supplied by private growers from the Australasian Native Orchid Society. Can Trigona carbonaria perceive a difference between pink and white flowers of Caladenia carnea? Colorimetric analysis of the pink and white Caladenia carnea flowers were used to investigate whether different colours of the orchid would be perceived as similar or different to a bees visual system. A spectrophotometer was used to take four measurements of each flower colour (pink versus white). The actual measurements used in the analysis were an average of each colour (Dyer, Whitney et al. 2007). To predict the probability with which insect pollinators would discriminate between different flowers, these spectra were plotted as loci in a hexagon colour space (Chittka 1992) (see hexagon colour space methods). Choice experiments I conducted trials testing the preferences of bees when offered a dichotomous choice between a white versus pink Caladenia carnea flower. Each trial took place inside a flight arena. Each white and pink flower used in a trial were matched for size, placed into indiviual plastic containers (diameter= 5 cm, height=5 cm) and placed in the arena with a distance of 10 cm between flower centres. Each container was covered with Glad WrapTM (The Clorox Company, Oaklands, CA, USA) to remove olfactory cues as they are known to inuence the choice behaviour of honeybees (e.g. Pelz, Gerber et al. 1997; Laska, Galizia et al. 1999). Approximately 50 bees were let into the arena for each trial. The rst contact made by a bee with the Glad WrapTM within a distance of 4 cm, was recorded as a choice of that ower (Dyer, Whitney et al. 2007). The number of landings were recorded to the flowers for five minutes. After each trial, the Glad WrapTM was changed to prevent scent marks. In addition, individual f lowers and spatial positions were randomised. Individual bees were sacrificed after each trial to avoid pseudo replication. Does the UV signal affect the attraction of bees to orchid flowers? To investigate whether the UV reectance of the dorsal sepal affected the response of bees, I offered bees the choice between two white orchids, one with a UV signal and the other without (N=16). The UV signal was removed by applying a thin layer of sunscreen (Hamilton SPF 30+, Adelaide, SA, Australia) over the dorsal sepal. Spectral reflectance measurements were taken to ensure that the sunscreen prevented any reflection of UV light (below 395 nm) from the sepals and did not change the reflectance properties of the orchid. In addition, spectral measurements of orchid sepals under Glad WrapTM confirmed that the foil was permeable to all wavelengths of light above 300 nm and did not obscure the reflectance of flowers. Do bees display preferences when choosing between pink versus white orchid flowers? To assess whether bees show a preference for pink or white variants of the orchid Caladenia carnea, I offered bees a simultaneous choice between a pink or white flower (N=16). See procedures for choice testing. Do bees habituate to non-rewarding orchids based on differences in floral coloration? I conducted a two stage experiment to investigate if bees could learn to habituate to a non-rewarding flower colour over time and whether bees adjusted their subsequent flower choice depending on the flower colour encountered previously. At stage 1 of the experiment, native bees were presented with one flower, either white or pink. Flowers were placed in a container with Glad WrapTM. Landings to the flower were recorded at the start and again at the 30 min mark. At stage 2, the flower from stage 1 was swapped with a new flower colour and the number of landings were scored for 5 minutes. Flowers were randomised and Glad WrapTM changed to prevent scent marks after each trial. Once again, bees were used only once per experiment. Statistical analyses For experiments 2, 3 4, numbers of landings by naive bees to flower pairs were compared using two tailed paired t-tests. A two factor ANOVA was used to analyse whether bees habituate to non-rewarding orchids based on differences in floral coloration. The dependent variable was the number of landings and the two independent variables were previous flower colour and new flower colour. 3. Results Part 1. Is there a link between hymenopteran vision and Australian floral coloration? Correlations between the inflection curves of different plant flowers and trichomatic vision of hymenopterans The analysis of 111 spectral reflection curves of Australian flowers reveals that sharp steps occur at those wavelengths where hymenoterans are most sensitive to spectral differences (fig. 4b). There are three clear peaks in sharp steps (fig. 4b). It is known that hymenopteran trichomats are all sensitive to spectral differences at approximately 400 and 500 nm (Menzel and Backhaus 1991; Peitsch, Fietz et al. 1992). Hence, the peaks at 400 and 500 nm can be discriminated well by hymenopteran trichomats, as illustrated by the inverse / function (solid curve shown in fig. 4a) of the honeybee (Helversen 1972), which is an empirically determined threshold function which shows the region of the electromagnetic function that a bees visual system discriminates colours best. In summary, the spectral position of receptors of trichomatic hymenopterans are correlates with steps in the floral spectra of Australian flowers. The distributions of Australian flower colours according to bees perception The floral colour loci are strongly clustered in the colour hexagon (fig. 5a). Blue-green flowers are the most common in the perception of bees, while pure UV flowers were the rarest (fig. 5b). Part 2. Does an Australian native bee (Trigona carbonaria) have innate colour preferences? Effect of brightness, spectral purity, chromatic contrast and green receptor contrast on colour choices There was no significant effect of stimulus brightness on choice frequency (rs= 0.333, n=10, p= 0.347; fig. 7a). There was no significant effect of spectral purity on choice frequency (rs = 0.224, n=10, p= 0.533; figure 7b). There was no significant correlation effect of chromatic contrast on choice frequency (rs = 0.042, n=10, p= 0.907; figure 7c). There was no significant effect of green receptor contrast on choice frequency (rs = 0. 0.552, n=10, p= 0.098; figure 7d). Effect of wavelength on colour choices Stimuli colours are plotted in figure 8a, as they appear to a human viewer to enable readers to understand the correlation between colour choices. However, all statistical analyses were conducted with stimuli plotted as wavelength due to the different visual perception of bees and humans (Kevan, Chittka et al. 2001). There is a significant effect of wavelength on the number of landings by Trigona carbonaria (Single factor ANOVA, F9,110 = 5.60, P 0.001), figure 8a. Tukeys post hoc test revealed that the wavelength of 437 nm (a white colour to a human viewer, but strongly coloured to a bees visual system as this stimulus does not reflect UV radiation) had significantly higher landings than other wavelengths of 528 nm (brown) (P0.01), 432 nm (grey) (P 0.01), 431 nm (light pink) (P0.01), 420 nm (purple) (P0.01), 455 nm (blue) (P=0.0196) and 535 nm (green) (P=0.0266). In addition, the number of landings to wavelengths of 530 nm (pale yellow) (P=0.0321) and 422 nm (pink) (P=0.0318) disks w ere significantly higher than that of 432 nm (grey) (figure 8a). Part 3. Does a food deceptive orchid (Caladenia carnea) exploit the innate colour preferences of Trigona carbonaria? Can Trigona carbonaria perceive a difference between pink and white flowers of Caladenia carnea? Ultraviolet photographs and reflectance measurements revealed that lateral sepals were different from the dorsal sepals (fig. 9). The spectra of the pink and white lateral sepals indicated no UV reflection. In contrast, the spectra of the dorsal sepals show reflection in the UV region (320-400 nm) (fig. 9b). Figure 10 shows the loci of the respective flower spectra in a hexagon colour space. Dyer and Chittka (2004) showed that with increasing colour distance between flowers and distractor flowers, less errors were made by foraging bees (fig. 11). Colour distance between the white and pink flowers is measured in hexagon units (Euclidean colour metric); Table 1. The lateral sepals (UV-) of pink and white flowers are separated by only 0.082 colour hexagon units, while pink and white dorsal sepals (UV+) are separated by 0.039 hexagon units. Thus, pink and white lateral sepals are distinguishable to a bee. In contrast, pink and white dorsal sepals (UV+) are perceptually similar to a bee. Therefore, the white vs. pink flowers of Caladenia carnea can thus be discriminated with between 70-90% accuracy (fig. 11). This means that visits to white/pink flower colours may results in occasional pollinator perceptual errors (1-3 errors/10 visits). Does the UV signal affect the attraction of bees to orchid flowers? When bees were presented with a choice between two white orchid flowers, one with a UV signal and one without, there was a significant preference for the flower with the UV reflectance (paired t-test: t= 6.949, df= 15, p0.001, n=16; figure 12). Do bees display preferences when choosing between pink versus white orchid flowers? When test subjects were presented with a choice between two flower colours, pink and white, there was a significant preference for the white flower (paired t-test: t= -3.484, df= 15, p= 0.003, n=16; figure 13). Do bees habituate to non-rewarding orchids based on differences in floral coloration? Bees were found to habituate to non-rewarding flowers, as the mean number of landings by Trigona carbonaria to the flower at the first time stage (T1) were found to be significantly different from the second time stage (T2) for white (paired t-test: t= 8.34, df= 15, p0.001) and pink flowers (paired t-test: t= 8.11, df= 15, p0.001) (fig. 14). Habituation rates were found to differ with different flower colours, as the mean number of landings by Trigona carbonaria to the white flower were found to be significantly higher from that of the pink flower (paired t-test: t=3.59, df=15, p=0.003, figure 14). I also looked at delta, which is calculated as the rate of change between landings at the first and second time stage for pink and white flowers separately. Hence, bees were found to habituate faster to pink flowers, as the rate of change was found to be significantly different (paired t-test: t=3.94, df=15, p=0.001). The number of landings to a flower were found to be significantly affect ed by the interaction between the previous flower colour and new flower colour, (two factor ANOVA, F3,28=6.846, p=0.001, figure 15). When the second flower colour presented was the same colour as the previous flower, landings were not significantly different to the second flower (F1,14=4.332 p=0.056). In contrast, when the second flower colour was different to the previous colour, landings were found to be significantly different to the second flower (F1,14=9.168 p=0.009) (fig. 15). In addition, preferences depended on the colour that bees were exposed to previously. When the previous flower was white, landings to the second pink or white flower were not found to be significantly different (F1,14=5.332,p=0.230). In contrast, when the previous flower colour was pink, landings were found to be significantly higher to the second white flower than to new pink flower (F1,14=8.395, p=0.012, figure 15). Bees, in this regard, were adjusting their choices to the second flower depending on their previous flower experience. 4. Discussion Hymenopteran vision and Australian floral coloration. Part 1 of this project aimed to investigate a possible link between hymenopteran vision and Australian floral coloration floral colour diversity My results suggest that the discrimination thresholds of hymenopterans match up with the Australian floral colours. These results are consistent with the study of Chittka and Menzel (1992), who found a correlation between flower spectra of different flowers and trichomatic vision of hymenopterans for flowers collected in Europe and parts of the Middle East. I have found a similar pattern in Australia, so this data is highly suggestive that hymenopterans appear to have been a major contributor to flower evolution in Australia. As bee vision predates the evolution of flower colours (Chittka 1996), one possibility is that Australian native flowers may initially have evolved to exploit the vision of hymenopteran species. Another alternative is that the existence of the current floral colours is due to phylogenetic constraints on the pigments in flower colours (Menzel and Shmida 1993). The distribution of flower colours that has evolved has a remarkably similar distribution to other parts of the world, such as Europe and the Middle East, where honeybees are the dominant pollinators (fig. 4a b, 5b c). Blue-green flowers were the most common as flower colours appear to a bee, while pure UV flowers were the rarest in the flowers sampled (fig. 5b). This result is similar to previous studies that found a similar cluster of blue-green flowers in Europe and Middle East (Chittka, Shmida et al. 1994). In that study, it was suggested that this cluster may be explained by the innate colour preferences of insects for certain colours (Chittka, Shmida et al. 1994). However, other studies contradict this because naive and experienced honeybees prefer UV-blue and blue colours over blue-green colours (Menzel 1967; Giurfa, Nez et al. 1995). However, the distribution of blue-green flowers is larger than that of UV-blue and blue flowers. The refore, Chittka (1997) suggested that the distribution could be caused by evolutionary constraints on the pigments of flower colours. Another theory for why flower colours are not evenly distributed in the colour space could be due to colour constancy (where bees only visit one flower type) in complex environments (Dyer 1999; Dyer and Chittka 2004). Hence, as there is no equal spacing of colours in the Australian floral coloration and there is a higher proportion of blue-green flowers, this may correspond to either pigment constraints in flowers or selective pressures by important pollinators like hymenopterans. There are two likely scenarios as to whether floral colours in Australia have evolved independently to those of Europe and the Middle East. First, angiosperms evolved after Australia separated from Gondwana. Hence, parallel evolution may have occurred where similar flower colours were being selected by hymenopteran trichomatic vision. The second possible scenario is that ang iosperms evolved before Australia separated from Gondwana and radiated out to all continents. Thus, flowering plants drifted with the moving land masses and evolved in a similar way to European and Middle Eastern flowers. Scenario 1, in this regard, seems more likely as the evolution of flowers in Australia is likely to be independent, based on work by Kevan and Backhaus (1998) who estimate that early angiosperms were most likely to be a pale yellow pollen colour and later evolved highly coloured signals to lure important pollinator vectors. It is estimated that the earliest angiosperm fossil dates at 132 million years ago (mya), around the early Cretaceous (Crane, Donoghue et al. 1989; Crane, Friis et al. 1995). Towards the end of the Cretaceous, Australia separated from Gondwana (Rich and Rich 1993). However, the time scales are too imprecise to conclusively resolve this question. Additional data is needed on biogeographical relationships and how this relates to floral reflectance data for other continents such as Africa, South America, Asia and North America to understand this question. The foraging success of a bee is dependent on the colour vision receptors being able to relialy distinguish flower species from each other (Chittka and Menzel 1992). There is a mutual benefit here as the pollinators foraging efficiency is increased if it can distinguish flowers from the surrounding background; and the plant is more likely to be pollinated if it appears distinct from its surroundings (Chittka and Menzel 1992). It is known that bees can discriminate colour stimuli best at 400 and 500 nm (Helversen 1972). So why, then, do we see a third peak at 600 nm (fig. 4b)? One reason could be that biological material (including leaves) reflect infrared radiation above 600 nm (Chittka, Shmida et al. 1994). There is also the possibility that insects with red receptors such as butterflies and beetles (Menzel and Backhaus 1991; Peitsch, Fietz et al. 1992) might also be important pollination vectors influencing the evolution of some Australian flower colours. Currently, there is very l ittle information within Australia about the vision of insects with long wavelength sensitive receptors, but this would provide an interesting avenue for future research. It was really important to not bias my data set by specifically picking species that are pollinated by only hymenopterans. Thus, I took a broad approach of including every flowering plant species available at my sampling site to best represent the colour distribution of Australian flowering plants that have evolved. This enabled me to test whether hymenopteran colour vision has been a major driving force shaping the evolution of floral colours. In spite of the fact that the dataset included a broad sample of plants (some of which would likely not even be pollinated by hymenopterans), strong patterns were detected, suggesting that hymenopterans may have been major players shaping the evolution of floral colours. Innate colour preferences of an Australian native bee In part 2 of the study, the simultaneous choices of naive bees (Trigona carbonaria) were tested for 10 different colours using articial owers. After each test, bees were sacrificed so all the data was independent, avoiding the risk of pseudo replication. In addition, the bees were not exposed to real flowers and reared on colour neutral disks prior to colour testing (fig. 6). Thus, their behaviour can be classified as innate (Giurfa, Nez et al. 1995). It was necessary to pre-train bees to land on aluminium disks because it was not possible to get bees to land on colour stimuli without previous training (Giurfa, Nez et al. 1995). I also tested whether bees preferred stimuli on the basis of brightness, spectral purity, contrast and green receptor contrast. My results showed that bees preferred stimuli irrespective of brightness, spectral purity, contrast and green receptor contrast (fig. 7). This was found to be consistent with the study by (Giurfa, Nez et al. 1995). Thus, the only sig nificant factor affecting bees choices was wavelength. The results revealed that Trigona carbonaria has innate preferences for wavelengths of 422, 437 and 530 nm (fig. 8b). These results are remarkably similar to the innate preferences of flower naive honeybees and bumblebees in Europe (Menzel 1967; Lunau 1990; Giurfa, Nez et al. 1995) that have innate preference for blue and violet. In those studies, it was suggested that the innate preference for blue correlates with blue and violet flowers having a slightly higher nectar reward than other flower colours in Europe (Giurfa, Nez et al. 1995; Chittka, Ings et al. 2004). In the same way, I hypothesise that these the innate preferences of Trigona carbonaria might correspond to Australian flowers colours that are more profitable to bees. Thus, future studies may want to look for correlations between the amounts of nectar in Australian native flowers versus different colour categories to see if nectar content may have fine-tuned the colour preferences of Australian stingless bees. Interactions between Australian stingless bees and a food deceptive orchid In part 3, the results illustrated that bees preferred flowers with a UV signal than those without (fig. 12). The results are in agreement with the study by Peter and Johnson (2008) who removed the UV component of the flower by using sunscreen, which reduced the number of pollinator visits. In a similar way, the UV signal of C. carnea is likely to be important in attracting naive bees to the flower. The UV-signal aside, I found that bees also significantly preferred the white flower colour over the pink flower colour (fig. 13). This result is consistent with part 2 of my study where I found that Trigona carbonaria showed innate preferences for certain colours over others. This could potentially result in fitness differences for the orchid depending on the colour of its flower. Here, it is possible that negative frequency-dependent selection may be important, with pollinators visiting the rarer morph and, in so doing, help retain floral colour variation (Smithson and Macnair 1997). Fo r example, negative frequency-dependent selection was found to influence flower colour variation in Dactylorhiza sambucina (Gigord, Macnair et al. 2001), where the rarer morph was visited more often. In a similar way, it is possible that negative frequency-dependent selection might be occurring in my system, but more information would be needed on the frequency of the two colours under natural field conditions. My results also reveal that bees were able to habituate to flowers on the basis of colour (fig. 14). This result in similar to the study by Simonds and Plowright (2004), who found that bumblebees habituated to colour paper disks and patterns, with a reduction in the number of landings over time. In that particular study, it was suggested that fatigue may have been responsible for bees habituating to colour disks. Another possibility is that bees were learning to habituate to the presence of unrewarding flower decoys through associative learning. Such a possibility is consistent with work carried out on the response of wasps that are exploited as pollinators by sexually deceptive orchids (Wong and Schiestl 2002; Wong, Salzmann et al. 2004). In those studies, it was found that males quickly learn the presence of unrewarding flowers and avoided flowers and locations where they had previously been deceived. Intriguingly, I found an increase in the number of landings to a newly introduced flower if it was a colour that the bee innately preferred, thus countering the habituation effect towards unrewarding orchids. It seems reasonable, therefore, that the existence of multiple flower colours in C. carnea could have fitness consequences for the orchid by making it more difficult for their pollinators to associate a particular colour with non-rewarding flowers. In nature, the number of visits a reward less orchid receives by naive pollinators also depends on ecological factors such as flowering time along with availability of other rewarding plants. Further studies might therefore like to take such factors into account. It is also important to point out that this study only examined visual cues. In nature, pollinators may obtain and assess information about their environment from a variety of visual and olfactory cues (Kunze and Gumbert 2001). The question of which cue has the greater influe nce on pollinator decisions warrants further investigation, and provides interesting avenues for future research with food-deceptive orchids. It is possible that group learning behaviour may have occurred in the habituation experiments. For example, previous studies have shown that insects can learn through transfer of social information (Worden and Papaj 2005; Leadbeater and Chittka 2007). It has been shown that bumblebee workers, for instance, can learn by observing others (Worden and Papaj 2005). However, it was not possible to control for group learning behaviour, as bees tested in isolation did not respond at all in pilot studies. To try and minimise the effects of group learning, however, bees were used only once and were removed after each trial so that each replicate was independent. Furthermore, although I controlled for floral scent in my study by using glad wrap, it was not possible to control for floral shape. Bees, in this regard, can also have preferences based on shape (Dafni, Lehrer et al. 1997; Kunze and Gumbert 2001; Galizia, Kunze et al. 2005). The orchid flower sepals in my experiments varied subtlety in shape (e.g. width). However, to control for this, flowers were completely randomised with respect to shape. In addition, evidence suggest that subtle differences in shape may not actually be perceived by bees due to their low acuity spatial vision (Land 1997; Land 1999). However, it would be interesting to test for shape preferences in the future. Conclusion and Future Directions In part 1, I found that the discrimination thresholds of hymenopterans match up with the with Australian floral coloration and that bees appear to have been a major contributor to flower evolution in Australia. In part 2, I found that Trigona carbonaria has innate preferences for wavelengths of 422, 437 and 530 nm, which might correspond to Australian flowers colours that are more profitable to bees. In part 3, I found that bees were able to habituate orchids based on colours (consistent with the data obtained in part 2). However, evidence also suggest that variation in flower colour could be an important strategy by C. carnea orchids to counter the bees capacity to learn and avoid unrewarding flower decoys. This study has highlighted a number of areas in which future research can advance our understanding of the exploitation of bee colour vision by flowers. Most work, to date, has focused on bees and flowers from Europe and it is surprising that very few studies have looked at the i nteraction between Australia bees and flowers. My study underscores the importance of further work in the Australian context for what it might reveal about general ecological, biogeographic and evolutionary patterns of plant-pollinator relationships. Acknowledgements My supervisors, Adrian Dyer and Bob Wong. Adrian thank you for the endless support, patience, sharing your knowledge about the exciting field of colour vision science and expanding my thinking beyond intellectual boundaries. Bob thank you for your exceptional levels of guidance, feedback, time and encouragement. You both inspired me to explore this topic with great enthusiasm. The culmination of two experts in their field with the right skills enabled me to do so much in this year. I hope that you both team up to supervise many honours students as this project has opened so many doors to explore. Vera Simonov, for being my field and research assistant and talking to me about things other than research. Andreas Svensson, for help with the stats. Melanie Norgate, for all the advice and encouragement. The behavioural ecology lab group, all the ideas and suggestions were invaluable. James, Ken, Lenny, Nikki, Wendy and Marianne for reading my various thesis drafts. Mani Shrestha and Dick Thomson, for putting me touch with the orchid society. The Caladenia carnea flowers were kindly supplied by Richard Austin and Russell Mawson of the Australasian Native Orchid Society (Victorian Group). Tim Heard and the CSIRO, for supplying the bees. Paul Birch and Andrea Dennis, the gardeners at Maranoa gardens, for letting me take flower samples and providing verbal information about the flora of Maranoa gardens. My fellow honours students for the sharing of ideas, stress and all the laughs, especially Emma Jensson and Kat Rajchl. I hope we stay great friends. Alanna, Kirsten, Mez, Wendy and Vera, thank you for the motivation, support and organising outings to take my mind away from research. And finally to Mum, Dad, Lenny, Harry and Lucy- for taking care of me and understanding that honours is really a hermit year, but its been a great one! Once again, thank you to you all for making the year a great success!

The Causes And Implications Of Childhood Obesity - 873 Words

It is widely argued that childhood obesity has gained a lot of attention in the recent years especially in the 21st century. It has the ability to affect a child in many ways, including physically, mentally, sociologically and psychologically. Childhood obesity is a serious health concern that is partially causes by the careless decisions about food intake, physical activity and lack of parental concerns and knowledge towards a child’s health. According to World Health Organization (WHO) childhood obesity is defined as a serious medical condition where a child has abnormal amount of body fat, which becomes a risk to their health. However, the body mass index (BMI) is the most common method employed in measuring obesity. The BMI is calculated by obtaining one’s weight (kg) and dividing it by their height in square metres. Nevertheless, this paper will discuss some of the causes and implications of the problem represented (Thom, 2007) along with some of the associated dis course, including the assumptions and what is left silenced (Thom, 2007). These topics will be discussed in consideration of Mills’ (1959) Sociological Imagination and also Bacchi’s (2009) WPR frameworks. A common risk factor that is presented within childhood obesity is the presence of parental or genetic genes. â€Å"Parents having obese genes increase the likelihood of obesity occurring by a factor of 12 for boys and a factor of 10 for girls.† (Phillip, 2012). This evidence is shown by a further increase forShow MoreRelatedHealthy Choices for Better Living Essay1588 Words   |  7 PagesDoes the media truly influence and play and key role in childhood obesity? Can we hold the media responsible for our food purchases and meals that we as a society choose to provide our children? Certainly there are a multitude of influences in the media and yes, they are geared toward our children. Commercials ran during children’s programming appeal to our youth with catchy jingles, bright colors and actors promoting these products that portray popular characters on our children’s favorite showsRead MoreNature Vs. Nurture : Childhood Obesity1510 Words   |  7 PagesIan Duffy Nature v. Nurture in Childhood Adiposity The nature versus nurture debate is one of the most longstanding arguments in the history of psychology and it aims to determine what has greater influence on personal development; one’s genes and inherited qualities compared to one’s environment. This debate is especially interesting in the study of childhood obesity. Childhood obesity is growing at an alarming rate in most developed countries throughout the world and it cannot be understatedRead MoreMaternal Obesity Induce Offspring with Risk of Cardiovascular Disease1700 Words   |  7 PagesMaternal obesity induce offspring with risk of cardiovascular disease Introduction: The rate of obesity for the human population has shown to be increased expeditiously in the past decades. It has continuously raised health concerns among the world, and is likely to remain in times to come. This phenomenon is primarily due to the lifestyle changes resulting in high-energy intake coupling with decreased physical activity (Cameron et al. 2003). Obesity is identified by the high adipose tissue,Read MoreCauses and Impact of Childhood Obesity1335 Words   |  5 PagesChildhood Obesity Childhood Obesity Obesity is a burgeoning and threatening epidemic that is becoming more pervasive in the United States and around the world as time goes on. While life expectancy in the United States continues to rise, the incidences of obesity-related diseases such as diabetes and cancer are rising alarmingly fast as well. Children are among the hardest hit as they are some of the more vulnerable members of society due to their inability to care for themselves in many waysRead MoreThe Effects Of Childhood Obesity: An Epidemic In Our Nation.1391 Words   |  6 PagesThe Effects of Childhood Obesity: An Epidemic in Our Nation Seema Patel A Capstone Proposal Presented in Partial Fulfillment of the Requirements for the Degree Master of Healthcare Administration KAPLAN UNIVERSITY March 2017 The Effects of Childhood Obesity: An Epidemic in Our Nation Childhood obesity is a greatest public health concern in our nation because it has an immediate and long-term effect on morbidity and mortality later in life. Experts in this epidemic suggest that there isRead MoreCauses And Effects Of Obesity In America870 Words   |  4 PagesThe Centers of Disease Control and Prevention defines obesity as having a BMI over 30 (CDC). In the year 2000, roughly 30 percent of 20 year olds in America were obese. By 2003 that number had risen to 32 percent. That is a small window of increase. From the 1970s to the early 2000s, the percent of obese Americans doubled. This means that in 1970, only 15 percent of Americans were obese, and in the thirty years following, obesity took a sharp rise. In 1960, 13 percent of Americans were obese. TheRead MoreDefining Overweight And Obesity : Bmi Interpretation1475 Words   |  6 Pages†¢ Defining overweight and obesity – BMI interpretation is review. The Body Mass Index (BMI) formula is used to estimate the proportion of fat a person has based on their HEIGHT and WEIGHT. Adults with a BMI between 18.5 and 24.9 are considered to be at a normal or healthy weight, adults with a BMI between 25 and 29.9 are considered to be overweight, and adults with a BMI of 30 or higher are considered obese. †¢ What challenges do people face in trying to lose weight, even when they know the healthRead MoreRisk Factors for Stroke in Young Adults1635 Words   |  7 Pages Risk Factors for Stroke in Young Adults Stroke is the third leading cause of death in the United States (CDC para. 1), affecting more than 7 million Americans over the age of 20 and representing 3% of the population (Rogers et al. e68). Current estimates suggest close to 800,000 Americans will experience a stroke each year; however, symptoms related to strokes often go undiagnosed. The prevalence of undiagnosed strokes is estimated to be 17.8% of the population over the age of 45, but some minoritiesRead MoreWhat Are The Causes Of Child Obesity?906 Words   |  4 PagesWhat are the Causes of Child Obesity? The rates of child obesity have been increasing in America, and there are more than nine million children between the ages of six to nine years old that are considered overweight (â€Å"Obesity Statistics†). A large percentage of these children are likely to be obese as adults. Lack of diet, exercise, and psychosocial environments are the main risk factors for child obesity. Our First Lady’s platform on child obesity has helped educate children and adults to becomeRead MoreThe Negative Side Effects Of Obesity On Human Body946 Words   |  4 Pages IELI2420 The Negative Side Effect Of Obesity on Human Body The rate of obesity has increased since 1970 to more than 30 %, more than two-thirds of Americans now are considered as overweight (Hojjat, 2015). Obesity is one of the problems that the world is facing nowadays. Obesity is a result of poor lifestyle and bad eating habits. Many people are suffering from the negative health consequences of obesity. In addition, many diseases are related to obesity such as heart diseases, high blood cholesterol