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‣ Crab spiders (Araneae: Thomisidae) in flowering plants in a Brazilian "Cerrado" ecosystem; Aranhas Thomisidae em plantas floridas de um ecossistema de Cerrado

ROCHA-FILHO, LC; RINALDI, IMP
Fonte: Instituto Internacional de Ecologia Publicador: Instituto Internacional de Ecologia
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
28.340864%
Although crab spiders are common in flowering plants, their relations with plant species and its floral traits have been poorly known in the Neotropics. Observations regarding plant habits, floral visitors and also floral characteristics such as anthesis, odour, shape, colour and floral resources were recorded in flowering plant species of an area of "Cerrado" on a 2 km long trail. Misumenops argenteus and Misumenops pallens accounted for 62.86% of the spiders captured on 22 flowering plant species. The plants Senna rugosa (Fabaceae), Styrax ferrugineus (Styracaceae) and Banisteriopsis campestris (Malpighiaceae), hosted, each one, about 10 to 17% of the total spiders collected and these plants had diurnal anthesis, bee-attractive flower colours such as yellow (S. rugosa), white (S. ferrugineus), and pink (B. campestris), poricidal anthers as well as being visited by bees which evidenced bee-pollination syndrome. This study is the first survey regarding crab spiders and their associations with plant species of the "Cerrado".; Ainda que aranhas Thomisidae sejam comumente encontradas em flores, as associações desses aracnídeos a espécies de plantas e às suas características florais foram pouco registradas na região neotropical. Observações do hábito das plantas...

‣ Crab spiders (Araneae: Thomisidae) in flowering plants in a Brazilian Cerrado ecosystem

Rocha-Filho, L. C.; Rinaldi, I. M. P.
Fonte: Instituto Internacional de Ecologia Publicador: Instituto Internacional de Ecologia
Tipo: Artigo de Revista Científica Formato: 359-364
Português
Relevância na Pesquisa
28.340864%
Ainda que aranhas Thomisidae sejam comumente encontradas em flores, as associações desses aracnídeos a espécies de plantas e às suas características florais foram pouco registradas na região neotropical. Observações do hábito das plantas, visitantes florais, e também das características florais, tais como antese, odor, forma, cor e recursos da flor, foram assinaladas para espécies floridas de uma área de cerrado presentes em uma trilha de 2 km de extensão. Misumenops argenteus e Misumenops pallens representaram 62,86% das aranhas habitantes de 22 espécies de plantas floridas. As plantas Senna rugosa (Fabaceae), Styrax ferrugineus (Styracaceae) e Banisteriopsis campestris (Malpighiaceae) abrigaram, individualmente, cerca de 10 a 17% do total das aranhas e, nestas plantas, a antese diurna; flores de coloração atrativa a abelhas, como amarela (S. rugosa), branca (S. ferrugineus) e rosa (B. campestris) e as anteras poricidas, bem como a visita das flores por abelhas reforçou a evidência de síndrome de polinização para melitofilia. Este é o primeiro levantamento de espécies de aranhas Thomisidae associadas a plantas do cerrado brasileiro.; Although crab spiders are common in flowering plants, their relations with plant species and its floral traits have been poorly known in the Neotropics. Observations regarding plant habits...

‣ Biologia floral e fragrâncias das flores de Passiflora L

Villamil Montero, Daniel Antonio
Fonte: Universidade Estadual Paulista (UNESP) Publicador: Universidade Estadual Paulista (UNESP)
Tipo: Dissertação de Mestrado Formato: vi, 52 f. : il. color., grafs. , tabs.
Português
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Pós-graduação em Agronomia (Horticultura) - FCA; As flores das espécies do gênero Passiflora têm recebido especial atenção por sua extraordinária beleza e complexidade da corola além de suas intensas fragrâncias. A presença de tecidos secretores de compostos voláteis (CVS) nas flores de Passiflora é muito variável, têm grande importância ecológica e prospecção econômica. Atualmente, só se tem registro dos CVs das fragrâncias florais de algumas poucas espécies, obtidos por meio de diferentes metodologias, com resultados variáveis. Durante os anos 2011 e 2012 foi desenvolvida uma pesquisa em parceria UNESP/FCA - Botucatu e Instituto Agronômico de Campinas (IAC) para estudar parâmetros da biologia floral e obter a primeira coleção brasileira dos perfis químicos das fragrâncias florais de cinco espécies de Passiflora L. (Passiflora edulis Sims., P. alata Curtis., P. cincinnata Mast., P. coccinea Aubl. e P. quadrangularis L.). As cinco espécies foram cultivadas em ambiente protegido. Os compostos voláteis das fragrâncias das flores de cada espécie foram capturados com a técnica de Headspace dinâmico (HSD) e as fragrâncias avaliadas através de teste olfativo. A análise da composição química das fragrâncias foi conduzida em cromatógrafo a gás acoplado a espectrômetro de massas e a identificação dos constituintes químicos foi efetuada através dos índices de retenção (IR) seguido da análise comparativa dos espectros de massas com diferentes bancos de dados especializados. Os resultados demonstraram que as espécies estudadas apresentam diferenças significativas na biologia floral...

‣ Aspectos da biologia floral de especies de Arrabidaea e Jacaranda, no Municipio de Botucatu, SP

Yuriko Yanagizawa
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em //1983 Português
Relevância na Pesquisa
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No presente trabalho, realizado no período compreendido entre agosto de 1978 a dezembro de 1981, foram estudados aspectos de biologiafloral de cinco espécies de Bigno­nlaceae Arrabidaea brachypoda (DC) BOR., Arrabidaea samydoides (CHAM.) SANDW., Arrabidaea -trip ZinerviaH.BAILL,Jacarandá decurrens CHAM. e Jacaranda oxyphyZZa CHAM., que ocorrem no município de Botucatu.As espécies de Bignoniaceae estudadas apresentam flores do tipo goela, com simetria zigomorfa e plataforma de pouso muito evidente. Exceto J. decurrens, a qual possui flores azuais, a cor das demais espécies é basicamente purpurea. As flores das espécies de Arrabidaea estudadas apresentam ântese diurna, produzem néctar em quantidade e odor agradável e intenso. As de Jacaranda apresentam ântese diurna, possuem nec­tar em pequena quantidade e odor agradável porém, pouco intenso e apesar destas diferenças, as características encontradas nas flores de Arrabidaea e Jacaranda podem ser atributos de flores melitófilas. Consideradas As espécies A. brachypodas A. samydoides eJ. oxyphyZZa são auto-compatíveis e J. decurrens, possivelmente auto-incompatível. As flores de todas estas espécies apresentam estratégias que impedem, até certo ponto, a auto-polinização (autogamia e geitonogamia). Assim...

‣ Morfologia e biologia floral de cinco especies de Passiflora L. (Passifloraceae)

Cristiana Koschnitzke
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 12/03/1993 Português
Relevância na Pesquisa
28.64319%
Foi realizado o estudo comparativo sobre a morfologia e a biologia floral de cinco especies de Passiflora (P. alata, P. amethystina, P. capsularis, P. miersii e P.suberosa), ocorrentes na Reserva Municipal de Santa Genebra. Passiflora alata, P. amethystina e P. miersii possuem flores com corona filamentosa de cor púrpura ao violeta, opérculo membranáceo que encobre a câmara nectarifera de formato campanulado. Florescem basicamente na estação chuvosa. Suas flores abrem no inicio da manhã e duram um dia, são perfumadas, a corona é um guia de néctar visual e olfativo, a concentração de açúcares do néctar mede de 31 a 41%, são autoincompativeis e sua polinização é feita por abelhas de grande porte. As morfologias florais de P. amethystina e P. miersii são semelhantes, diferindo de P. alata por apresentarem no opérculo filamentos livres em sua parte superior. Em P. alata o opérculo é horizontal e denticulado. Estas caracteristicas do opérculo exigem das abelhas um comportamento distinto durante as visitas. Passiflora suberosa possui flores inconspicuas, verdeamareladas, com corona de duas séries de filamentos, opérculo plicado e câmara nectarifera de formato anular. Floresce durante o ano todo. As flores abrem às 06:00h e duram apenas um dia. são inodoras...

‣ Crab spiders (Araneae: Thomisidae) in flowering plants in a Brazilian "Cerrado" ecosystem

Rocha-Filho,LC; Rinaldi,IMP
Fonte: Instituto Internacional de Ecologia Publicador: Instituto Internacional de Ecologia
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/05/2011 Português
Relevância na Pesquisa
28.29311%
Although crab spiders are common in flowering plants, their relations with plant species and its floral traits have been poorly known in the Neotropics. Observations regarding plant habits, floral visitors and also floral characteristics such as anthesis, odour, shape, colour and floral resources were recorded in flowering plant species of an area of "Cerrado" on a 2 km long trail. Misumenops argenteus and Misumenops pallens accounted for 62.86% of the spiders captured on 22 flowering plant species. The plants Senna rugosa (Fabaceae), Styrax ferrugineus (Styracaceae) and Banisteriopsis campestris (Malpighiaceae), hosted, each one, about 10 to 17% of the total spiders collected and these plants had diurnal anthesis, bee-attractive flower colours such as yellow (S. rugosa), white (S. ferrugineus), and pink (B. campestris), poricidal anthers as well as being visited by bees which evidenced bee-pollination syndrome. This study is the first survey regarding crab spiders and their associations with plant species of the "Cerrado".

‣ Floral to green: mating switches moth olfactory coding and preference

Saveer, Ahmed M.; Kromann, Sophie H.; Birgersson, Göran; Bengtsson, Marie; Lindblom, Tobias; Balkenius, Anna; Hansson, Bill S.; Witzgall, Peter; Becher, Paul G.; Ignell, Rickard
Fonte: The Royal Society Publicador: The Royal Society
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
39.04709%
Mating induces profound physiological changes in a wide range of insects, leading to behavioural adjustments to match the internal state of the animal. Here, we show for the first time, to our knowledge, that a noctuid moth switches its olfactory response from food to egg-laying cues following mating. Unmated females of the cotton leafworm (Spodoptera littoralis) are strongly attracted to lilac flowers (Syringa vulgaris). After mating, attraction to floral odour is abolished and the females fly instead to green-leaf odour of the larval host plant cotton, Gossypium hirsutum. This behavioural switch is owing to a marked change in the olfactory representation of floral and green odours in the primary olfactory centre, the antennal lobe (AL). Calcium imaging, using authentic and synthetic odours, shows that the ensemble of AL glomeruli dedicated to either lilac or cotton odour is selectively up- and downregulated in response to mating. A clear-cut behavioural modulation as a function of mating is a useful substrate for studies of the neural mechanisms underlying behavioural decisions. Modulation of odour-driven behaviour through concerted regulation of odour maps contributes to our understanding of state-dependent choice and host shifts in insect herbivores.

‣ Thermogenesis, Flowering and the Association with Variation in Floral Odour Attractants in Magnolia sprengeri (Magnoliaceae)

Wang, Ruohan; Xu, Sai; Liu, Xiangyu; Zhang, Yiyuan; Wang, Jianzhong; Zhang, Zhixiang
Fonte: Public Library of Science Publicador: Public Library of Science
Tipo: Artigo de Revista Científica
Publicado em 12/06/2014 Português
Relevância na Pesquisa
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Magnolia sprengeri Pamp. is an ornamentally and ecologically important tree that blooms at cold temperatures in early spring. In this study, thermogenesis and variation in the chemical compounds of floral odours and insect visitation in relation to flowering cycles were studied to increase our understanding of the role of floral thermogenesis in the pollination biology of M. sprengeri. There were five distinct floral stages across the floral cycle of this species: pre-pistillate, pistillate, pre-staminate, staminate and post-staminate. Floral thermogenesis during anthesis and consisted of two distinct peaks: one at the pistillate stage and the other at the staminate stage. Insects of five families visited M. sprengeri during the floral cycle, and sap beetles (Epuraea sp., Nitidulidae) were determined to be the most effective pollinators, whereas bees (Apis cerana, Apidae) were considered to be occasional pollinators. A strong fragrance was released during thermogenesis, consisting of 18 chemical compounds. Although the relative proportions of these compounds varied at different floral stages across anthesis, linalool, 1-iodo-2-methylundecane and 2,2,6-trimethyl-6-vinyltetrahydro-2H-pyran-3-ol were dominant. Importantly, we found that the floral blends released during the pistillate and staminate stages were very similar...

‣ The evolutionary biology of pollination: studies in a genus of australian sexually deceptive orchids

Whitehead, Michael Robert
Fonte: Universidade Nacional da Austrália Publicador: Universidade Nacional da Austrália
Tipo: Thesis (PhD); Doctor of Philosophy (PhD)
Português
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There are few other structures in nature from which evolution has generated such wide diversity as the flower or inflorescence, and this diversity is commonly attributed to the influence of their animal visitors. By outsourcing their mate choice to pollinators, plants have left themselves - and especially their flowers - subject to the selective forces imposed by the behaviour, cognition and perception of the pollinators that serve them. The orchids provide some of the most remarkable and extreme examples of adaptations to specific animal pollinators. Perhaps one of the most peculiar of these strategies is sexual deception, whereby male insects are lured to the flower by mimicry of the female sex pheromone. This seemingly unlikely strategy has evolved multiple times independently on different continents in different parts of the orchid phylogeny which raises the question of what adaptive advantages might underlie such a strategy. This multidisciplinary thesis studies gene flow and pollinator behaviour in two sympatric sexually deceptive orchids in the genus Chiloglottis. The two species attract their specific wasp pollinators through emission of distinct species - specific semiochemicals. Since floral volatiles play a pre-eminent role in pollinator attraction...

‣ Mismatch in the distribution of floral ecotypes and pollinators: insights into the evolution of sexually deceptive orchids

Phillips, R. D.; Bohman, B.; Anthony, J. M.; Krauss, S. L.; Dixon, K. W.; Peakall, R.
Fonte: Wiley Publicador: Wiley
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
48.01341%
Plants are predicted to show floral adaptation to geographic variation in the most effective pollinator, potentially leading to reproductive isolation and genetic divergence. Many sexually deceptive orchids attract just a single pollinator species, limiting opportunities to experimentally investigate pollinator switching. Here, we investigate Drakaea concolor, which attracts two pollinator species. Using pollinator choice tests, we detected two morphologically similar ecotypes within D. concolor. The common ecotype only attracted Zaspilothynnus gilesi, whereas the rare ecotype also attracted an undescribed species of Pogonothynnus. The rare ecotype occurred at populations nested within the distribution of the common ecotype, with no evidence of ecotypes occurring sympatrically. Surveying for pollinators at over 100 sites revealed that ecotype identity was not correlated with wasp availability, with most orchid populations only attracting the rare Z. gilesi. Using microsatellite markers, genetic differentiation among populations was very low (GST = 0.011) regardless of ecotype, suggestive of frequent gene flow. Taken together, these results may indicate that the ability to attract Pogonothynnus has evolved recently, but this ecotype is yet to spread. The nested distribution of ecotypes...

‣ Moth pollination, low seed set, and vestigialization of attractive floral traits in Abronia umbellata (Nyctaginaceae)

Doubleday, LAURA
Fonte: Quens University Publicador: Quens University
Tipo: Tese de Doutorado
Português
Relevância na Pesquisa
38.378237%
Flowering plants display remarkable phenotypic diversity, especially in reproductive structures, much of which is thought to be associated with pollination by animals. Pollination syndromes are collections of floral traits (e.g. flower colour, shape, odour) that are associated with a plant attracting particular functional groups of animal pollinators. We explored the extent to which traits associated with the moth pollination syndrome translated into pollination by moths in the Pacific coast dune endemic Abronia umbellata and found mixed results: in one year of study, there was no difference in seed set by day- vs. night-pollinated inflorescences, but in another year of study, night-pollinated inflorescences set significantly more seed than those pollinated during the day. We integrate this work with tests of pollen and resource limitation of seed production and with seed set surveys of natural populations to address proximate and ultimate causes of low seed set, finding low rates of pollinator visitation, high pollen limitation of seed production in all populations studied, and no evidence of endogenous resource limitation of seed production. We propose that “excess” flowers may be functionally male, serving to increase outcross siring success. The transition from self-incompatibility and obligate outcrossing to self-compatibility and predominant selfing is the most common evolutionary transition among the flowering plants and traits associated with outcrossing may become reduced across such shifts...

‣ Biologia floral de duas especies sincronopatricas de Prestonia (Apocynaceae)

Andrea L. M. Franco
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 06/02/1991 Português
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28.841558%
Observações sobre biologia floral, sistema de reprodução e polinização de Prestonia coalita e P. riedelii foram realizadas no período de janeiro a abril de 1989 e 1990 na Reserva Municipal da Mata de Santa Genebra, Campinas, São Paulo. Prestonia coalita possui flores tubulosas, medindo de 11 a 13mm de comprimento, de coloração amarelo-oliva e odor acre e doce. Os estames são epipétalos, inclusos na corola e localizam-se acima do estigma. O estigma tem a forma característica de um carretel e apresenta duas regiões separadas pelo anel estigmático: a região superior que é estéril e coberta por uma substância de aspecto mucilaginoso e a região inferior que é receptiva. O néctar é produzido em quantidade na base do tubo floral e possui uma concentração de açúcares, em média de 17%, variando de 12 a 20%. As flores de P. riedelii são de coloração amarela com regiões de cor amarelobronze, odor adocicado e apresentam organização morfológica semelhante à das flores de P. coahta sendo que o seu tubo floral é ligeiramente mais longo. O néctar é produzido em menor quantidade que em P. coalita e possui uma concentração de açúcares, em média de 40%, variando de 30 a 64%. P. coalt"tae P. riedelii são alógamas. Uma vez que ocorre separação espacial entre os orgãos sexuais não há autopolinização espontânea. Além disso...

‣ Differential Interactions of Sex Pheromone and Plant Odour in the Olfactory Pathway of a Male Moth

Deisig, Nina; Kropf, Jan; Vitecek, Simon; Pevergne, Delphine; Rouyar, Angela; Sandoz, Jean-Christophe; Lucas, Philippe; Gadenne, Christophe; Anton, Sylvia; Barrozo, Romina
Fonte: Public Library of Science Publicador: Public Library of Science
Tipo: Artigo de Revista Científica
Publicado em 12/03/2012 Português
Relevância na Pesquisa
37.90383%
Most animals rely on olfaction to find sexual partners, food or a habitat. The olfactory system faces the challenge of extracting meaningful information from a noisy odorous environment. In most moth species, males respond to sex pheromone emitted by females in an environment with abundant plant volatiles. Plant odours could either facilitate the localization of females (females calling on host plants), mask the female pheromone or they could be neutral without any effect on the pheromone. Here we studied how mixtures of a behaviourally-attractive floral odour, heptanal, and the sex pheromone are encoded at different levels of the olfactory pathway in males of the noctuid moth Agrotis ipsilon. In addition, we asked how interactions between the two odorants change as a function of the males' mating status. We investigated mixture detection in both the pheromone-specific and in the general odorant pathway. We used a) recordings from individual sensilla to study responses of olfactory receptor neurons, b) in vivo calcium imaging with a bath-applied dye to characterize the global input response in the primary olfactory centre, the antennal lobe and c) intracellular recordings of antennal lobe output neurons, projection neurons, in virgin and newly-mated males. Our results show that heptanal reduces pheromone sensitivity at the peripheral and central olfactory level independently of the mating status. Contrarily...

‣ Diesel exhaust rapidly degrades floral odours used by honeybees

Girling, Robbie D.; Lusebrink, Inka; Farthing, Emily; Newman, Tracey A.; Poppy, Guy M.
Fonte: Nature Publishing Group Publicador: Nature Publishing Group
Tipo: Artigo de Revista Científica
Publicado em 03/10/2013 Português
Relevância na Pesquisa
39.066853%
Honeybees utilise floral odours when foraging for flowers; we investigated whether diesel exhaust pollution could interrupt these floral odour stimuli. A synthetic blend of eight floral chemicals, identified from oilseed rape, was exposed to diesel exhaust pollution. Within one minute of exposure the abundances of four of the chemicals were significantly lowered, with two components rendered undetectable. Honeybees were trained to recognise the full synthetic odour mix; altering the blend, by removing the two chemicals rendered undetectable, significantly reduced the ability of the trained honeybees to recognize the altered odour. Furthermore, we found that at environmentally relevant levels the mono-nitrogen oxide (NOx) fraction of the exhaust gases was a key facilitator of this odour degradation. Such changes in recognition may impact upon a honeybee's foraging efficiency and therefore the pollination services that they provide.

‣ Insect odour perception: recognition of odour components by flower foraging moths

Cunningham, John Paul; Moore, Chris J; Zalucki, Myron P; Cribb, Bronwen W
Fonte: The Royal Society Publicador: The Royal Society
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
38.83731%
Odours emitted by flowers are complex blends of volatile compounds. These odours are learnt by flower-visiting insect species, improving their recognition of rewarding flowers and thus foraging efficiency. We investigated the flexibility of floral odour learning by testing whether adult moths recognize single compounds common to flowers on which they forage. Dual choice preference tests on Helicoverpa armigera moths allowed free flying moths to forage on one of three flower species; Argyranthemum frutescens (federation daisy), Cajanus cajan (pigeonpea) or Nicotiana tabacum (tobacco). Results showed that, (i) a benzenoid (phenylacetaldehyde) and a monoterpene (linalool) were subsequently recognized after visits to flowers that emitted these volatile constituents, (ii) in a preference test, other monoterpenes in the flowers' odour did not affect the moths' ability to recognize the monoterpene linalool and (iii) relative preferences for two volatiles changed after foraging experience on a single flower species that emitted both volatiles. The importance of using free flying insects and real flowers to understand the mechanisms involved in floral odour learning in nature are discussed in the context of our findings.

‣ Efectos inhibitorios sobre el aprendizaje olfativo en la abeja doméstica (Apis mellifera); Inhibitory effects on olfactory learning in the honey bee (Apis mellifera)

Fernández, Vanesa Maribel
Fonte: Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires Publicador: Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires
Tipo: info:eu-repo/semantics/doctoralThesis; tesis doctoral; info:eu-repo/semantics/publishedVersion Formato: application/pdf
Publicado em //2012 Português
Relevância na Pesquisa
28.916274%
Entre los múltiples estímulos percibidos del entorno, los animales deben ser capaces de seleccionar aquellos que les sean útiles para sobrevivir. A tal efecto, las experiencias previas permiten diferenciar los estímulos relevantes de aquellos que no lo son; en especial esta Tesis se focalizará en los relacionados con la búsqueda y obtención de alimento. Cuando se pretende asociar un estímulo, que ha sido preexpuesto en el ambiente, a una recompensa, puede resultar difícil establecer una contingencia entre ellos. Este fenómeno ha sido definido como inhibición latente (IL) y se lo ha explorado a lo largo de esta Tesis usando como modelo experimental a la abeja Apis mellifera. A partir de ensayos de condicionamiento olfativo se evaluaron los efectos de volátiles preexpuestos tanto en el contexto social de la colmena como bajo condiciones experimentales controladas. Los volátiles preexpuestos en una colmena reducen las preferencias de las abejas hacia una fuente de alimento aromatizada con ese olor. Además, durante un condicionamiento clásico evaluado bajo el protocolo de extensión de probóscide, la preexposición olfativa dificulta la adquisición de una relación predictiva entre el olor preexpuesto y una recompensa. Esta reducción en el aprendizaje varía con la identidad del olor...

‣ Honeybees Learn Odour Mixtures via a Selection of Key Odorants

Reinhard, Judith; Sinclair, Michael; Srinivasan, Mandyam V.; Claudianos, Charles
Fonte: Public Library of Science Publicador: Public Library of Science
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
28.304316%
BACKGROUND The honeybee has to detect, process and learn numerous complex odours from her natural environment on a daily basis. Most of these odours are floral scents, which are mixtures of dozens of different odorants. To date, it is still unclear how the bee brain unravels the complex information contained in scent mixtures. METHODOLOGY/PRINCIPAL FINDINGS This study investigates learning of complex odour mixtures in honeybees using a simple olfactory conditioning procedure, the Proboscis-Extension-Reflex (PER) paradigm. Restrained honeybees were trained to three scent mixtures composed of 14 floral odorants each, and then tested with the individual odorants of each mixture. Bees did not respond to all odorants of a mixture equally: They responded well to a selection of key odorants, which were unique for each of the three scent mixtures. Bees showed less or very little response to the other odorants of the mixtures. The bees' response to mixtures composed of only the key odorants was as good as to the original mixtures of 14 odorants. A mixture composed of the other, non-key-odorants elicited a significantly lower response. Neither an odorant's volatility or molecular structure, nor learning efficiencies for individual odorants affected whether an odorant became a key odorant for a particular mixture. Odorant concentration had a positive effect...

‣ Pollinator specificity, floral odour chemistry and the phylogeny of Australian sexually deceptive Chiloglottis orchids: implications for pollinator-driven speciation

Peakall, Rodney; Ebert, Daniel; Poldy, Jacqueline; Barrow, Russell; Francke, Wittko; Bower, Colin; Schiestl, F P
Fonte: Cambridge University Press Publicador: Cambridge University Press
Tipo: Artigo de Revista Científica
Português
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37.803628%
•Sexually deceptive orchids are predicted to represent a special case of plant speciation where strong reproductive isolation may be achieved by differences in floral scent. •In this study of Australian sexually deceptive Chiloglottis orchids, we perf

‣ Chemical communication in the sexually deceptive orchid genus Cryptostylis

Schiestl, Florian; Peakall, Rodney; Mant, J
Fonte: Blackwell Publishing Ltd Publicador: Blackwell Publishing Ltd
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
38.304316%
Pollination by sexual deception is among the most intriguing of orchid pollination syndromes. Odours are well established as the primary stimuli for sexually attracting the male insect pollinators in these orchids. We applied gas chromatography with electroantennographic detection (GC-EAD) to investigate chemical communication between the sympatric, but morphologically distinct, orchids Cryptostylis erecta and C. subulata and their pollinators. Cryptostylis is unusual among sexually deceptive orchid genera in that all five Australian species share the same pollinator, the ichneumonid wasp Lissopimpla excelsa, but hybrids are unknown. We show that volatile odour compounds are not produced in detectable amounts in either species. Floral extracts containing many low-volatility compounds showed considerable differences in composition between C. erecta and C. subulata. By contrast, GC-EAD revealed the male wasp pollinators are electrophysiologically responsive to the same GC peak on two different kinds of GC column in both orchids. This leads us to predict that a single compound is the sexual attractant in all Australian Cryptostylis. The apparent conservation of chemical signals among distinct species contrasts with that of other sexually deceptive orchids that are often morphologically similar but reproductively isolated by their different chemical signals.

‣ Two orchids attract different pollinators with the same floral odour compound: ecological and evolutionary implications

Schiestl, Florian; Peakall, Rodney
Fonte: Blackwell Publishing Ltd Publicador: Blackwell Publishing Ltd
Tipo: Artigo de Revista Científica
Português
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1. The sexually deceptive orchids Chiloglottis trapeziformis Fitzg. and Chiloglottis valida D.L. Jones are pollinated by the thynnine wasps Neozeleboria cryptoides (Smith) and Neozeleboria monticola Turner, respectively, during attempted mating with the flower labellum. The orchids and their pollinators occur mostly in allopatry; however on the overlapping edges of their ranges they can attract each other's pollinator, leading to rare hybrids. 2. Using gas chromatographic analyses with electroantennographic detection (GC-EAD) we demonstrate that 2-ethyl-5-propyl-1,3-cyclohexandione ('Chiloglottone'), the previously known sex pheromone of N. cryptoides and pollinator-attractant of C. trapeziformis, is also used by C. valida to attract its pollinator N. monticola. 3. In behavioural field experiments, equal numbers of males of both species responded to, and attempted copulation with, a dummy scented with synthetic Chiloglottone. In dualchoice experiments where dummies were presented at different heights, N. cryptoides males preferentially attempted copulation with dummies a few centimetres above the ground, while N. monticola males significantly more often landed on the soil and attempted copulation with dummies on the soil. 4. These behavioural differences corresponded with differences in floral height in the orchids...