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Hirota SK, Nitta K, Suyama Y, Kawakubo N, Yasumoto AA, Yahara T. Pollinator-mediated selection on flower color, flower scent and flower morphology of Hemerocallis: evidence from genotyping individual pollen grains on the stigma. PLoS One 2013; 8:e85601. [PMID: 24376890 PMCID: PMC3871637 DOI: 10.1371/journal.pone.0085601] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2013] [Accepted: 11/29/2013] [Indexed: 11/18/2022] Open
Abstract
To trace the fate of individual pollen grains through pollination processes, we determined genotypes of single pollen grains deposited on Hemerocallis stigmas in an experimental mixed-species array. Hemerocallis fulva, pollinated by butterflies, has diurnal, reddish and unscented flowers, and H. citrina, pollinated by hawkmoths, has nocturnal, yellowish and sweet scent flowers. We observed pollinator visits to an experimental array of 24 H. fulva and 12 F2 hybrids between the two species (H. fulva and H. citrina) and collected stigmas after every trip bout of swallowtail butterflies or hawkmoths. We then measured selection by swallowtail butterflies or hawkmoths through male and female components of pollination success as determined by single pollen genotyping. As expected, swallowtail butterflies imposed selection on reddish color and weak scent: the number of outcross pollen grains acquired is a quadratic function of flower color with the maximum at reddish color, and the combined pollination success was maximal at weak scent (almost unrecognizable for human). This explains why H. fulva, with reddish flowers and no recognizable scent, is mainly pollinated by swallowtail butterflies. However, we found no evidence of hawkmoths-mediated selection on flower color or scent. Our findings do not support a hypothesis that yellow flower color and strong scent intensity, the distinctive floral characteristics of H. citrina, having evolved in adaptations to hawkmoths. We suggest that the key trait that triggers the evolution of nocturnal flowers is flowering time rather than flower color and scent.
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Affiliation(s)
- Shun K. Hirota
- Department of Biology, Faculty of Sciences, Kyushu University, Fukuoka, Japan
| | - Kozue Nitta
- Department of Biology, Faculty of Sciences, Kyushu University, Fukuoka, Japan
| | - Yoshihisa Suyama
- Field Science Center, Graduate School of Agricultural Science, Tohoku University, Osaki, Miyagi, Japan
| | - Nobumitsu Kawakubo
- Department of Environmental Science, Faculty of Applied Biological Sciences, Gifu University, Gifu, Japan
| | - Akiko A. Yasumoto
- Department of Biology, Faculty of Sciences, Kyushu University, Fukuoka, Japan
| | - Tetsukazu Yahara
- Department of Biology, Faculty of Sciences, Kyushu University, Fukuoka, Japan
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Abstract
Background Combinations of floral traits – which operate as attractive signals to pollinators – act on multiple sensory modalities. For Manduca sexta hawkmoths, how learning modifies foraging decisions in response to those traits remains untested, and the contribution of visual and olfactory floral displays on behavior remains unclear. Methodology/Principal Findings Using M. sexta and the floral traits of two important nectar resources in southwestern USA, Datura wrightii and Agave palmeri, we examined the relative importance of olfactory and visual signals. Natural visual and olfactory cues from D. wrightii and A. palmeri flowers permits testing the cues at their native intensities and composition – a contrast to many studies that have used artificial stimuli (essential oils, single odorants) that are less ecologically relevant. Results from a series of two-choice assays where the olfactory and visual floral displays were manipulated showed that naïve hawkmoths preferred flowers displaying both olfactory and visual cues. Furthermore, experiments using A. palmeri flowers – a species that is not very attractive to hawkmoths – showed that the visual and olfactory displays did not have synergistic effects. The combination of olfactory and visual display of D. wrightii, however – a flower that is highly attractive to naïve hawkmoths – did influence the time moths spent feeding from the flowers. The importance of the olfactory and visual signals were further demonstrated in learning experiments in which experienced moths, when exposed to uncoupled floral displays, ultimately chose flowers based on the previously experienced olfactory, and not visual, signals. These moths, however, had significantly longer decision times than moths exposed to coupled floral displays. Conclusions/Significance These results highlight the importance of specific sensory modalities for foraging hawkmoths while also suggesting that they learn the floral displays as combinatorial signals and use the integrated floral traits from their memory traces to mediate future foraging decisions.
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Abstract
The hawkmoth, Manduca sexta, uses both colour and odour to find flowers when foraging for nectar. In the present study we investigated how vision and olfaction interact during learning. Manduca sexta were equally attracted to a scented blue coloured feeding target (multimodal stimulus) as to one that does not carry any scent (unimodal stimulus; visual) or to an invisible scented target (unimodal stimulus; odour). This naive attraction to multimodal as well as to unimodal stimuli could be manipulated through training. Moths trained to feed from a blue, scented multimodal feeding target will, when tested in a set-up containing all three feeding targets, select the multimodal target as well as the scented, unimodal target, but ignore the visual target. Interestingly, moths trained to feed from a blue, unimodal visual feeding target will select the visual target as well as the scented, multimodal target, but ignore the unimodal odour target. Our results indicate that a multimodal target is perceived as two separate modalities, colour and odour, rather than as a unique fused target. These findings differ from earlier studies of desert ants that perceive combined visual and odour signals as a unique fused stimulus following learning trials.
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Dell'Olivo A, Kuhlemeier C. ASYMMETRIC EFFECTS OF LOSS AND GAIN OF A FLORAL TRAIT ON POLLINATOR PREFERENCE. Evolution 2013; 67:3023-31. [DOI: 10.1111/evo.12178] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2013] [Accepted: 04/28/2013] [Indexed: 01/10/2023]
Affiliation(s)
- Alexandre Dell'Olivo
- Institute of Plant Sciences; University of Bern; Altenbergrain 21; CH-3013 Bern; Switzerland
| | - Cris Kuhlemeier
- Institute of Plant Sciences; University of Bern; Altenbergrain 21; CH-3013 Bern; Switzerland
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The effect of ambient humidity on the foraging behavior of the hawkmoth Manduca sexta. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2013; 199:1053-63. [PMID: 23756587 DOI: 10.1007/s00359-013-0829-3] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2013] [Revised: 05/14/2013] [Accepted: 05/16/2013] [Indexed: 10/26/2022]
Abstract
The foraging decisions of flower-visiting animals are contingent upon the need of an individual to meet both energetic and osmotic demands. Insects can alter their food preferences to prioritize one need over the other, depending on environmental conditions. In this study, preferences in nectar sugar concentrations (0, 12, 24 %) were tested in the hawkmoth Manduca sexta, in response to different levels of ambient humidity (20, 40, 60, and 80 % RH). Moths altered their foraging behavior when placed in low humidity environments by increasing the volume of nectar imbibed and by consuming more dilute nectar. When placed in high humidity environments the total volume imbibed decreased, because moths consumed less from dilute nectars (water and 12 % sucrose). Survivorship was higher with higher humidity. Daily foraging patterns changed with relative humidity (RH): moths maximized their nectar consumption earlier, at lower humidities. Although ambient humidity had an impact on foraging activity, activity levels and nectar preferences, total energy intake was not affected. These results show that foraging decisions made by M. sexta kept under different ambient RH levels allow individuals to meet their osmotic demands while maintaining a constant energy input.
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56
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Martins DJ, Johnson SD. Interactions between hawkmoths and flowering plants in East Africa: polyphagy and evolutionary specialization in an ecological context. Biol J Linn Soc Lond 2013. [DOI: 10.1111/bij.12107] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Dino J. Martins
- School of Life Sciences; University of KwaZulu-Natal; Private Bag X01, Scottsville; Pietermaritzburg; 3209; South Africa
| | - Steven D. Johnson
- School of Life Sciences; University of KwaZulu-Natal; Private Bag X01, Scottsville; Pietermaritzburg; 3209; South Africa
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57
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Schiestl FP, Johnson SD. Pollinator-mediated evolution of floral signals. Trends Ecol Evol 2013; 28:307-15. [PMID: 23480953 DOI: 10.1016/j.tree.2013.01.019] [Citation(s) in RCA: 302] [Impact Index Per Article: 27.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2012] [Revised: 01/30/2013] [Accepted: 01/30/2013] [Indexed: 12/27/2022]
Abstract
Because most plants rely on animals for pollination, insights from animal sensory ecology and behavior are essential for understanding the evolution of flowers. In this review, we compare and contrast three main types of pollinator responses to floral signals--receiver bias, 'adaptive' innate preferences, and associative learning--and discuss how they can shape selection on floral signals. We show that pollinator-mediated selection on floral signals can be strong and that the molecular bases of floral signal variation are often surprisingly simple. These new empirical and conceptual insights into pollinator-mediated evolution provide a framework for understanding patterns of both convergent (pollination syndromes) and advergent (floral mimicry) floral signal evolution.
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Affiliation(s)
- Florian P Schiestl
- Institute of Systematic Botany, University of Zurich, Zollikerstrasse 107, CH-8008 Zürich, Switzerland.
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58
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Whitehead MR, Peakall R. Short-term but not long-term patch avoidance in an orchid-pollinating solitary wasp. Behav Ecol 2012. [DOI: 10.1093/beheco/ars149] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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59
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Hirota SK, Nitta K, Kim Y, Kato A, Kawakubo N, Yasumoto AA, Yahara T. Relative role of flower color and scent on pollinator attraction: experimental tests using F1 and F2 hybrids of daylily and nightlily. PLoS One 2012; 7:e39010. [PMID: 22720016 PMCID: PMC3376114 DOI: 10.1371/journal.pone.0039010] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2012] [Accepted: 05/15/2012] [Indexed: 11/22/2022] Open
Abstract
The daylily (Hemerocallis fulva) and nightlily (H. citrina) are typical examples of a butterfly-pollination system and a hawkmoth-pollination system, respectively. H. fulva has diurnal, reddish or orange-colored flowers and is mainly pollinated by diurnal swallowtail butterflies. H. citrina has nocturnal, yellowish flowers with a sweet fragrance and is pollinated by nocturnal hawkmoths. We evaluated the relative roles of flower color and scent on the evolutionary shift from a diurnally flowering ancestor to H. citrina. We conducted a series of experiments that mimic situations in which mutants differing in either flower color, floral scent or both appeared in a diurnally flowering population. An experimental array of 6 × 6 potted plants, mixed with 24 plants of H. fulva and 12 plants of either F1 or F2 hybrids, were placed in the field, and visitations of swallowtail butterflies and nocturnal hawkmoths were recorded with camcorders. Swallowtail butterflies preferentially visited reddish or orange-colored flowers and hawkmoths preferentially visited yellowish flowers. Neither swallowtail butterflies nor nocturnal hawkmoths showed significant preferences for overall scent emission. Our results suggest that mutations in flower color would be more relevant to the adaptive shift from a diurnally flowering ancestor to H. citrina than that in floral scent.
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Affiliation(s)
- Shun K. Hirota
- Department of Biology, Faculty of Sciences, Kyushu University, Fukuoka, Japan
| | - Kozue Nitta
- Department of Biology, Faculty of Sciences, Kyushu University, Fukuoka, Japan
| | - Yuni Kim
- Department of Environmental Science, Faculty of Applied Biological Sciences, Gifu University, Gifu, Japan
| | - Aya Kato
- Department of Environmental Science, Faculty of Applied Biological Sciences, Gifu University, Gifu, Japan
| | - Nobumitsu Kawakubo
- Department of Environmental Science, Faculty of Applied Biological Sciences, Gifu University, Gifu, Japan
| | - Akiko A. Yasumoto
- Department of Biology, Faculty of Sciences, Kyushu University, Fukuoka, Japan
| | - Tetsukazu Yahara
- Department of Biology, Faculty of Sciences, Kyushu University, Fukuoka, Japan
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60
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Brandenburg A, Kuhlemeier C, Bshary R. Innate Adjustment of Visitation Behavior to Rewarding and Reward-Minimized Petunia axillaris (Solanacea) Plants by Hawkmoth Manduca sexta (Sphingidae). Ethology 2012. [DOI: 10.1111/j.1439-0310.2012.02055.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
| | - Cris Kuhlemeier
- Institute of Plant Science; University of Bern; Bern; Switzerland
| | - Redouan Bshary
- Institute of Biology; University of Neuchâtel; Neuchâtel; Switzerland
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61
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Kaczorowski RL, Seliger AR, Gaskett AC, Wigsten SK, Raguso RA. Corolla shape vs. size in flower choice by a nocturnal hawkmoth pollinator. Funct Ecol 2012. [DOI: 10.1111/j.1365-2435.2012.01982.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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62
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Young M, Salmon M, Forward R. Visual wavelength discrimination by the loggerhead turtle, Caretta caretta. THE BIOLOGICAL BULLETIN 2012; 222:46-55. [PMID: 22426631 DOI: 10.1086/bblv222n1p46] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Marine turtles are visual animals, yet we know remarkably little about how they use this sensory capacity. In this study, our purpose was to determine whether loggerhead turtles could discriminate between objects on the basis of color. We used light-adapted hatchlings to determine the minimum intensity of blue (450 nm), green (500 nm), and yellow (580 nm) visual stimuli that evoked a positive phototaxis (the phototaxis "threshold" [pt]). Juvenile turtles were later trained to associate each color (presented at 1 log unit above that color's pt) with food, then to discriminate between two colors (the original rewarded stimulus plus one of the other colors, not rewarded) when both were presented at 1 log unit above their pt. In the crucial test, turtles were trained to choose between the rewarded and unrewarded color when the colors varied in intensity. All turtles learned that task, demonstrating color discrimination. An association between blue and food was acquired in fewer trials than between yellow and food, perhaps because some prey of juvenile loggerheads in oceanic surface waters (jellyfishes, polyps, and pelagic gastropods) are blue or violet in color.
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Affiliation(s)
- Morgan Young
- Department of Biological Sciences, Florida Atlantic University, Boca Raton, 33431, USA
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63
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Kulbaba MW, Worley AC. Selection on floral design in Polemonium brandegeei (Polemoniaceae): female and male fitness under hawkmoth pollination. Evolution 2012; 66:1344-59. [PMID: 22519776 DOI: 10.1111/j.1558-5646.2011.01536.x] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Plant-pollinator interactions promote the evolution of floral traits that attract pollinators and facilitate efficient pollen transfer. The spatial separation of sex organs, herkogamy, is believed to limit sexual interference in hermaphrodite flowers. Reverse herkogamy (stigma recessed below anthers) and long, narrow corolla tubes are expected to promote efficiency in male function under hawkmoth pollination. We tested this prediction by measuring selection in six experimental arrays of Polemonium brandegeei, a species that displays continuous variation in herkogamy, resulting in a range of recessed to exserted stigmas. Under glasshouse conditions, we measured pollen removal and deposition, and estimated selection gradients (β) through female fitness (seeds set) and male fitness (siring success based on six polymorphic microsatellite loci). Siring success was higher in plants with more nectar sugar and narrow corolla tubes. However, selection through female function for reverse herkogamy was considerably stronger than was selection through male function. Hawkmoths were initially attracted to larger flowers, but overall preferred plants with reverse herkogamy. Greater pollen deposition and seed set also occurred in reverse herkogamous plants. Thus, reverse herkogamy may be maintained by hawkmoths through female rather than male function. Further, our results suggest that pollinator attraction may play a considerable role in enhancing female function.
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Affiliation(s)
- Mason W Kulbaba
- Department of Biological Sciences, University of Manitoba, Winnipeg, Manitoba R3T 2N2, Canada.
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64
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Delle-Vedove R, Juillet N, Bessière JM, Grison C, Barthes N, Pailler T, Dormont L, Schatz B. Colour-scent associations in a tropical orchid: three colours but two odours. PHYTOCHEMISTRY 2011; 72:735-742. [PMID: 21377705 DOI: 10.1016/j.phytochem.2011.02.005] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2010] [Revised: 02/01/2011] [Accepted: 02/07/2011] [Indexed: 05/30/2023]
Abstract
Colour and scent are the major pollinator attractants to flowers, and their production may be linked by shared biosynthetic pathways. Species with polymorphic floral traits are particularly relevant to study the joint evolution of floral traits. We used in this study the tropical orchid Calanthe sylvatica from Réunion Island. Three distinct colour varieties are observed, presenting lilac, white or purple flowers, and named respectively C. sylvaticavar.lilacina (hereafter referred as var. lilacina), C. sylvaticavar. alba (var. alba) and C. sylvatica var. purpurea (var. purpurea). We investigated the composition of the floral scent produced by these colour varieties using the non-invasive SPME technique in the wild. Scent emissions are dominated by aromatic compounds. Nevertheless, the presence of the terpenoid (E)-4,8-dimethylnona-1,3,7-triène (DMNT) is diagnostic of var. purpurea, with the volatile organic compounds (VOC) produced by some individuals containing up to 60% of DMNT. We evidence specific colour-scent associations in C. sylvatica, with two distinct scent profiles in the three colour varieties: the lilacina-like profile containing no or very little DMNT (<2%) and the purpurea-like profile containing DMNT (>2%). Calanthe sylvatica var. alba individuals group with one or the other scent profile independently of their population of origin. We suggest that white-flowered individuals have evolved at least twice, once from var. lilacina and at least once from var. purpurea after the colonisation of la Réunion. White-flowered individuals may have been favoured by the particular pollinator fauna characterising the island. These flowering varieties of C. sylvatica, which display three colours but two scents profiles prove that colour is not always a good indicator of odour and that colour-scent associations may be complex, depending on pollination ecology of the populations concerned.
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Affiliation(s)
- Roxane Delle-Vedove
- Centre d'Ecologie Fonctionnelle et Evolutive (CEFE), UMR CNRS 5175, Montpellier, France.
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65
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Blackiston D, Briscoe AD, Weiss MR. Color vision and learning in the monarch butterfly, Danaus plexippus (Nymphalidae). ACTA ACUST UNITED AC 2011; 214:509-20. [PMID: 21228210 DOI: 10.1242/jeb.048728] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The monarch butterfly, Danaus plexippus, is well known for its intimate association with milkweed plants and its incredible multi-generational trans-continental migrations. However, little is known about monarch butterflies' color perception or learning ability, despite the importance of visual information to butterfly behavior in the contexts of nectar foraging, host-plant location and mate recognition. We used both theoretical and experimental approaches to address basic questions about monarch color vision and learning ability. Color space modeling based on the three known spectral classes of photoreceptors present in the eye suggests that monarchs should not be able to discriminate between long wavelength colors without making use of a dark orange lateral filtering pigment distributed heterogeneously in the eye. In the context of nectar foraging, monarchs show strong innate preferences, rapidly learn to associate colors with sugar rewards and learn non-innately preferred colors as quickly and proficiently as they do innately preferred colors. Butterflies also demonstrate asymmetric confusion between specific pairs of colors, which is likely a function of stimulus brightness. Monarchs readily learn to associate a second color with reward, and in general, learning parameters do not vary with temporal sequence of training. In addition, monarchs have true color vision; that is, they can discriminate colors on the basis of wavelength, independent of intensity. Finally, behavioral trials confirm that monarchs do make use of lateral filtering pigments to enhance long-wavelength discrimination. Our results demonstrate that monarchs are proficient and flexible color learners; these capabilities should allow them to respond rapidly to changing nectar availabilities as they travel over migratory routes, across both space and time.
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Affiliation(s)
- Douglas Blackiston
- Department of Biology, 406 Reiss Bldg., Georgetown University, 37th & O Sts. NW, Washington, DC 20057 USA
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66
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Goyret J. Look and touch: multimodal sensory control of flower inspection movements in the nocturnal hawkmoth Manduca sexta. J Exp Biol 2010; 213:3676-82. [DOI: 10.1242/jeb.045831] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
SUMMARY
A crucial stage in the interaction between pollinators and plants is the moment of physical contact between them, known as flower inspection, or handling. Floral guides – conspicuous colour markings, or structural features of flower corollas – have been shown to be important in the inspecting behaviour of many insects, particularly in diurnal species. For the nocturnal hawkmoth Manduca sexta tactile input has an important role in flower inspection, but there is no knowledge about the use of visual floral guides in this behaviour. I carried out a series of experiments to first, evaluate the putative role of floral guides during flower inspection and second, to explore how simultaneous tactile and visual guides could influence this behaviour. Results show that visual floral guides affect flower inspection by M. sexta. Moths confine proboscis placement to areas of higher light reflectance regardless of their chromaticity, but do not appear to show movements in any particular direction within these areas. I also recorded inspection times, finding that moths can learn to inspect flowers more efficiently when visual floral guides are available. Additionally, I found that some visual floral guides can affect the body orientation that moths adopt while hovering in front of horizontal models. Finally, when presented with flower models offering both visual and tactile guides, the former influenced proboscis placement, whereas the latter controlled proboscis movements. Results show that innate inspection behaviour is under multimodal sensory control, consistent with other components of the foraging task. Fine scale inspection movements (elicited by diverse floral traits) and the tight adjustment between the morphology of pollinators and flowers appear to be adaptively integrated, facilitating reward assessment and effective pollen transfer.
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Affiliation(s)
- Joaquín Goyret
- Department of Neurobiology and Behavior, Seeley G. Mudd Hall, Cornell University, Ithaca, NY 14853, USA
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67
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68
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Balkenius A, Balkenius C. Behaviour towards an unpreferred colour: can green flowers attract foraging hawkmoths? J Exp Biol 2010; 213:3257-62. [DOI: 10.1242/jeb.045161] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
SUMMARY
Naïve hawkmoths (Manduca sexta) learn from a single trial to approach and attempt to feed from an artificial flower of an innately unpreferred green colour even when a distractor flower with a preferred yellow colour is present. In some of the animals, the choice of the innately unpreferred colour during free-flight testing persists for several days despite not being rewarded and eventually leads to starvation. The results show that moths exhibit a very strong flower constancy that is not limited to the colours of nectar flowers.
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Affiliation(s)
- Anna Balkenius
- Chemical Ecology, Swedish University of Agricultural Sciences, Department of Chemical Ecology, Box 102, Vaxthusvagen 3, Alnarp 230 53, Sweden
| | - Christian Balkenius
- Lund University Cognitive Science, Kungshuset, Lundagård, Lund 222 22, Sweden
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69
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Kelber A. What a hawkmoth remembers after hibernation depends on innate preferences and conditioning situation. Behav Ecol 2010. [DOI: 10.1093/beheco/arq115] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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71
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Kelber A, Osorio D. From spectral information to animal colour vision: experiments and concepts. Proc Biol Sci 2010; 277:1617-25. [PMID: 20164101 DOI: 10.1098/rspb.2009.2118] [Citation(s) in RCA: 112] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Many animals use the spectral distribution of light to guide behaviour, but whether they have colour vision has been debated for over a century. Our strong subjective experience of colour and the fact that human vision is the paradigm for colour science inevitably raises the question of how we compare with other species. This article outlines four grades of 'colour vision' that can be related to the behavioural uses of spectral information, and perhaps to the underlying mechanisms. In the first, even without an (image-forming) eye, simple organisms can compare photoreceptor signals to locate a desired light environment. At the next grade, chromatic mechanisms along with spatial vision guide innate preferences for objects such as food or mates; this is sometimes described as wavelength-specific behaviour. Here, we compare the capabilities of di- and trichromatic vision, and ask why some animals have more than three spectral types of receptors. Behaviours guided by innate preferences are then distinguished from a grade that allows learning, in part because the ability to learn an arbitrary colour is evidence for a neural representation of colour. The fourth grade concerns colour appearance rather than colour difference: for instance, the distinction between hue and saturation, and colour categorization. These higher-level phenomena are essential to human colour perception but poorly known in animals, and we suggest how they can be studied. Finally, we observe that awareness of colour and colour qualia cannot be easily tested in animals.
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Affiliation(s)
- Almut Kelber
- Department of Biology, Lund University, Helgonavägen 3, 22362 Lund, Sweden.
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72
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El Jundi B, Huetteroth W, Kurylas AE, Schachtner J. Anisometric brain dimorphism revisited: Implementation of a volumetric 3D standard brain in Manduca sexta. J Comp Neurol 2009; 517:210-25. [PMID: 19731336 DOI: 10.1002/cne.22150] [Citation(s) in RCA: 84] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Lepidopterans like the giant sphinx moth Manduca sexta are known for their conspicuous sexual dimorphism in the olfactory system, which is especially pronounced in the antennae and in the antennal lobe, the primary integration center of odor information. Even minute scents of female pheromone are detected by male moths, facilitated by a huge array of pheromone receptors on their antennae. The associated neuropilar areas in the antennal lobe, the glomeruli, are enlarged in males and organized in the form of the so-called macroglomerular complex (MGC). In this study we searched for anatomical sexual dimorphism more downstream in the olfactory pathway and in other neuropil areas in the central brain. Based on freshly eclosed animals, we created a volumetric female and male standard brain and compared 30 separate neuropilar regions. Additionally, we labeled 10 female glomeruli that were homologous to previously quantitatively described male glomeruli including the MGC. In summary, the neuropil volumes reveal an isometric sexual dimorphism in M. sexta brains. This proportional size difference between male and female brain neuropils masks an anisometric or disproportional dimorphism, which is restricted to the sex-related glomeruli of the antennal lobes and neither mirrored in other normal glomeruli nor in higher brain centers like the calyces of the mushroom bodies. Both the female and male 3D standard brain are also used for interspecies comparisons, and may serve as future volumetric reference in pharmacological and behavioral experiments especially regarding development and adult plasticity. J. Comp. Neurol. 517:210-225, 2009. (c) 2009 Wiley-Liss, Inc.
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Affiliation(s)
- Basil El Jundi
- Department of Biology, Animal Physiology, Philipps-University, Marburg, Germany
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Goyret J. The breath of a flower: CO(2) adds another channel-and then some-to plant-pollinator interactions. Commun Integr Biol 2009; 1:66-8. [PMID: 19513201 DOI: 10.4161/cib.1.1.6119] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2008] [Accepted: 04/16/2008] [Indexed: 11/19/2022] Open
Abstract
In this article I comment on our findings that floral carbon dioxide (CO(2)) can be used by Manduca sexta hawkmoths in a scale- and context-dependent fashion. We firstly found, in wind tunnel assays, that diffusing floral CO(2) is used as long-distance cue (e.g., meters). Moths track CO(2) plumes up-wind in the same manner they track floral odors. Nevertheless, CO(2) did not appear to function as a local stimulus for flower probing, evidencing a scale-dependent role in nectar foraging. These results were further enriched by a second finding. In dual choice assays, where moths were offered two scented artificial flowers of which only one emitted above-ambient CO(2)-levels, female Manduca sexta chose to feed on the CO(2) emitting flower only when host-plant volatiles were added to the background. We discuss this apparent measurement of oviposition obligations during foraging in the context of the life histories of both insect and plant species. These findings seem to pinpoint the usually artificial nature of compartmentalizing herbivory and pollination as different, isolated aspects of insect-plant interactions. Insects do not seem to have a defined response to a certain stimulus; instead, motor programs appear to be in response to composite arrangements of external stimuli and inner states. If animal-plant interactions have evolved under these premises, I believe it may prove beneficial to include a non-linear, integrative view of plant multi-signaling and life history aspects into the study of pollination biology.
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Affiliation(s)
- Joaquín Goyret
- Department of Neurobiology and Behavior; Cornell University; Ithaca, New York USA
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Goyret J, Kelber A, Pfaff M, Raguso RA. Flexible responses to visual and olfactory stimuli by foraging Manduca sexta: larval nutrition affects adult behaviour. Proc Biol Sci 2009; 276:2739-45. [PMID: 19419987 DOI: 10.1098/rspb.2009.0456] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Here, we show that the consequences of deficient micronutrient (beta-carotene) intake during larval stages of Manduca sexta are carried across metamorphosis, affecting adult behaviour. Our manipulation of larval diet allowed us to examine how developmental plasticity impacts the interplay between visual and olfactory inputs on adult foraging behaviour. Larvae of M. sexta were reared on natural (Nicotiana tabacum) and artificial laboratory diets containing different concentrations of beta-carotene (standard diet, low beta-carotene, high beta-carotene and cornmeal). This vitamin-A precursor has been shown to be crucial for photoreception sensitivity in the retina of M. sexta. After completing development, post-metamorphosis, starved adults were presented with artificial feeders that could be either scented or unscented. Regardless of their larval diet, adult moths fed with relatively high probabilities on scented feeders. When feeders were unscented, moths reared on tobacco were more responsive than moths reared on beta-carotene-deficient artificial diets. Strikingly, moths reared on artificial diets supplemented with increasing amounts of beta-carotene (low beta and high beta) showed increasing probabilities of response to scentless feeders. We discuss these results in relationship to the use of complex, multi-modal sensory information by foraging animals.
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Affiliation(s)
- Joaquín Goyret
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA.
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Balkenius A, Bisch-Knaden S, Hansson B. Interaction of visual and odour cues in the mushroom body of the hawkmoth Manduca sexta. ACTA ACUST UNITED AC 2009; 212:535-41. [PMID: 19181901 DOI: 10.1242/jeb.021220] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The responses to bimodal stimuli consisting of odour and colour were recorded using calcium-sensitive optical imaging in the mushroom bodies of the hawkmoth Manduca sexta. The results show that the activity in the mushroom bodies is influenced by both olfaction and vision. The interaction between the two modalities depends on the odour and the colour of the visual stimulus. A blue stimulus suppressed the response to a general flower scent (phenylacetaldehyde). By contrast, the response to a green leaf scent (1-octanol) was enhanced by the presence of the blue stimulus. A green colour had no influence on these odours but caused a marked increase in the response to an odour component (benzaldehyde) of the hawkmoth-pollinated Petunia axillaris.
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Affiliation(s)
- Anna Balkenius
- Department of Chemical Ecology, Swedish University of Agricultural Science, Sundsvägen 14, S-230 53, Alnarp, Sweden.
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