How specialist bees distinguish their host plants from co-blooming non-hosts is not well understood, but it is thought that they may be physiologically limited in their ability to recognize the majority of visual and olfactory cues presented by flowering plants. Species in the genus Diadasia collect pollen from just one of five plant families: Cactaceae, Malvaceae, Onagraceae, Asteraceae, and Convolvulaceae. Assuming a common ancestor for all Diadasia specialized on just one plant, this indicates host-switches in the past, and an ability to recognize more than one flowering plant. I hypothesized that host plants of Diadasia share the same visual and olfactory cues, thus enabling past host-switching to novel plant families, and that co-blooming non-hosts are highly dissimilar in terms of scent and visual appearance. I determined the compounds associated with the scent of Malvaceae and Cactaceae host flowers of North American Diadasia. I also evaluated visual cues for these flowers by measuring their full spectrum of reflected wavelengths, as well as select morphometric characters. I determined whether host flowers, regardless of taxa, were more similar to each other than non-hosts that were co-blooming and attractive to other bee species. Finally, I performed electroantennographic and behavioral experiments to assess the relative importance of these cues (visual and olfactory) in natural settings. Diadasia host plants share some chemical and visual characteristics that may in part explain the radiation of this group onto these particular hosts. First, host plants share a suite of scent compounds that are among the least variable across species. Many of these elicited antennal responses and did not decrease visitation when applied to host flowers. In contrast, some compounds produced by non-host flowers are detectable to Diadasia, but Diadasia are repelled by them when they are applied to host flowers. Diadasia host flowers do not share a color profile in common, but there is more reflectance in the bee-uv range as compared to other regions of the light spectrum. Also, Diadasia host flowers have a more contrasting central area that is relatively larger than in non-hosts.

Most Aphidinae species produce and use (E)-ß-farnesene (Eßf) as an alarm pheromone. This sesquiterpene is released by individuals under attack by a predator, and nearby aphids exhibit a variety of alarm behaviours. This PhD thesis aims to better understand how aphids manage their production and emission of alarm pheromone (Chapter IV). We also wanted, in a second step, to improve our knowledge on the roles that Eßf could play in the relationships that aphids have with their predators (Chapter V) and tending ants (Chapter VI), in order to better pinpoint the problem in this very tough context. The aphid predators have indeed a real advantage to be able to use the odorant cues emitted by their prey, to locate them and to select an adequate oviposition site. Ants establish with certain aphid species mutualistic relationships, which occurrence could be facilitated by the use of aphids odours. In Chapter IV, we have highlighted that aphid colonies non subjected to attack by predators release constantly small quantities of Eßf in their headspace, which means that this molecule could have additional roles than just acting as an alarm pheromone. In a second study, we demonstrated that the release of Eßf was not contagious, and therefore that a non stressed aphid receiving the alarm signal does not release additional Eßf. Since the production of alarm pheromone is likely to entail physiological cost, we tested and validated the hypothesis that aphids regulate their Eßf production according to their social environment. In Chapter V, we studied the ability of the hoverfly predator Episyrphus balteatus (Diptera, Syrphidae) to be used as biological control agent against aphids infesting tomato plants (Lycopersicon esculentum). After identifying the odours emitted by aphid infested plants, we have demonstrated that although this Diptera is able to perceive all the odours released by the system, it mainly uses Eßf to select its oviposition site. However, the E. balteatus larvae are not adapted to the architecture of tomato plants. We also showed that the Asian ladybeetle Harmonia axyridis (Coleoptera, Coccinellidae) olfaction was adapted to the perception of Eßf and that this beetle is also attracted by this sesquiterpene. Finally, in Chapter VI, we characterized the benefits accruing to aphid populations that have established mutualistic relationships with Lasius niger (Hymenoptera, Formicidae), and have demonstrated the role of Eßf and honeydew, respectively in locating aphid colonies and in the persistence of the mutualism. La plupart des espèces de pucerons appartenant à la sous-famille des Aphidinae produisent et utilisent le (E)-ß-farnésène (Eßf) comme phéromone dalarme. Ce sesquiterpène est relargué par les individus stressés par lattaque dun prédateur et cause chez les individus qui le perçoivent un comportement dalerte. La présente thèse de doctorat a pour objectif de comprendre comment les pucerons gèrent la production et émission de phéromones dalarme (Chapitre IV). Nous voulions aussi, dans une seconde étape, améliorer les connaissances sur les rôles potentiels que cet Eßf peut jouer au sein des relations que les pucerons entretiennent avec leurs prédateurs (Chapitre V) et avec les fourmis (Chapitre VI) Les prédateurs de pucerons retirent en effet un réel avantage à pouvoir saider des odeurs émises par leurs proies pour les localiser et pour sélectionner un site doviposition adéquat. Les fourmis, quant à elles, établissent des relations de mutualisme avec certaines espèces de pucerons. Les rencontres entre fourmis et pucerons pourraient être facilitées par lutilisation des odeurs de pucerons. Les résultats obtenus peuvent être résumés de la manière suivante: Dans le chapitre IV, nous avons mis en évidence que les colonies de pucerons non soumises à lattaque de prédateurs relarguent constamment de faibles quantités dEßf, ce qui permet dassumer que cette molécule puisse avoir dautres fonctions que celle de phéromone dalarme. Dans une deuxième étude, nous avons démontré que lémission du Eßf nétait pas contagieuse, et donc quun puceron non stressé percevant le signal dalarme német pas à son tour de le Eßf. Puisque la production de phéromone dalarme a inévitablement un coût physiologique, nous avons testé et validé lhypothèse selon laquelle les pucerons régulent leur production de Eßf en fonction de leur environnement social. Dans le chapitre V, nous avons étudié la possibilité dutiliser le syrphe prédateur Episyrphus balteatus (Diptera, Syrphidae) en lutte biologique contre les pucerons infestant les plants de tomate (Lycopersicon esculentum). Après avoir identifié les odeurs émises par les plants infestés, nous avons démontré que, si ce Diptère est capable de percevoir lensemble des odeurs émises par ce système tritrophique, il utilise principalement lEßf pour sélectionner son site doviposition. Cependant, les larves dE. balteatus ne sont pas adaptées à larchitecture des plants de tomate. Nous avons également montré que la coccinelle asiatique Harmonia axyridis (Coleoptera, Coccinellidae) possède le matériel olfactif nécessaire à la perception du Eßf et quelle est aussi attirée par ce sesquiterpène. Enfin, dans le chapitre VI, nous avons caractérisé les bénéfices retirés par les populations de pucerons ayant établi des relations de mutualisme avec Lasius niger (Hymenoptera, Formicidae), et avons démontré le rôle du Eßf et du miellat, respectivement dans la localisation des colonies de pucerons et dans la persistance du mutualisme.

Submitted by Irene Nascimento (irene.kessia@ufpe.br) on 2017-03-08T17:39:39Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Dissertação Rayane Silva biblioteca.pdf: 1013981 bytes, checksum: d8b76305e22b14cf85166327afe7da53 (MD5) / Made available in DSpace on 2017-03-08T17:39:39Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Dissertação Rayane Silva biblioteca.pdf: 1013981 bytes, checksum: d8b76305e22b14cf85166327afe7da53 (MD5) Previous issue date: 2013-02-28 / FACEPE / O Aedes aegypti é um mosquito de grande importância epidemiológica por ser o vetor de viroses como a febre amarela e a dengue estando distribuído entre as regiões tropicais e subtropicais do globo. A fim de encontrar uma forma alternativa de combate ao mosquito, objetivou-se avaliar no presente estudo, a caracterização química do óleo essencial de Commiphora leptophloeos e sua atividade biológica frente A. aegypti através de análises eletrofisiológicas, testes de atividade larvicida, repelente e deterrente de oviposição. As análises por cromatografia gasosa acoplada a espectrometria de massa revelaram a presença de 55 compostos no óleo essencial de C. leptophloeos sendo o α- Felandreno, trans- Cariofileno e β- Felandreno os constituintes do óleo presentes em maior proporção, representando 26,26%, 18,01% e 12,93% respectivamente. Através de cromatografia gasosa acoplada à detecção eletroantenográfica foram obtidas 17 respostas aos constituintes do óleo, sendo em sua maioria a sesquiterpenos, estando entre elas o trans- Cariofileno, um dos compostos majoritários do óleo. A partir dos testes comportamento de oviposição com fêmeas grávidas de A. aegypti foi possível observar que o óleo essencial de C. leptophloeos apresentou atividade deterrente de oviposição nas concentrações de 100, 50 e 25 ppm, sendo a média de ovos deixadas no recipiente de teste menor que o depositado no controle (p<0,008). Testes de oviposição também foram realizados com o composto majoritário do óleo o α-Felandreno, e dois compostos que apresentaram respostas eletrofisiológicas (trans- Cariofileno e α-Humuleno). O α-Felandreno não demonstrou atividade significativa. O trans- Cariofileno, em contrapartida, se mostrou deterrente de oviposição (p<0,004), assim como o α-Humuleno (p<0,003). O óleo de C. leptophloeos não demonstrou atividade biológica em relação ao teste de repelência em olfatômetro de dupla escolha. A atividade larvicida foi constatada com CL50 de 99,4 ppm. Nesse contexto, os resultados demonstram que o óleo essencial de C. leptophloeos é uma fonte promissora de compostos que induzem respostas comportamentais em fêmeas de A. aegypti que buscam por um sítio de oviposição, havendo respostas deterrentes entre os diferentes compostos, além de atuar como agente larvicida. / Aedes aegypti has a large epidemiological importance for being the vector of viruses, such as yellow fever and dengue fever, being distributed across the tropical and subtropical regions of the globe. To find an alternative way for eradicating the mosquito, in this study it was evaluated the chemical characterization of the essential oil of Commiphora leptophloeos and its biological activity against A. aegypti through electrophysiological analyzes and tests of larvicidal activity, repellent and oviposition deterrent. The analysis by gas chromatography-mass spectrometry revealed the presence of 55 compounds in the essential oil of C. leptophloeos being the α-phellandrene, trans-caryophyllene and β-phellandrene the constituents present in greater proportion, representing 26.26%, 18.01% and 12.93% respectively. By gas chromatography- electroantennographic detection were obtained 17 responses to the constituents of the oil, most of them being the sesquiterpenes, among them trans-Caryophyllene, one of the major compounds from the oil. From behavior for oviposition, tests with pregnant females of A. aegypti reveled that the essential oil of C. leptophloeos showed oviposition deterrent activity at concentrations of 100, 50 and 25 ppm and the average of eggs left on the test vessel was smaller than the average deposited in the control vessel. Oviposition test were also carried out with the α-phellandrene, the major compound of the oil, and two compounds that showed electrophysiological responses (trans-caryophyllene and α-humulene). The α-phellandrene showed no significant activity. The trans-Caryophyllene, in contrast, showed oviposition deterrent (p <0.004), as well as α-Humulene (p <0.003). The oil of C. leptophloeos not demonstrated biological activity against the test repellency dual choice olfactometer. The larvicidal activity was observed with LC50 of 99.4 ppm. In this context, the results show that the essential oil of C. leptophloeos is a promising source of compounds that induce behavioral responses in female of A. aegypti seeking for an oviposition site, with answers deterrents between the different compounds, in addition to acting as an agent larvicide.

Les zones pastorales méditerranéennes sont favorables à la diversité et à l’abondance des Tabanidae. Or, la réémergence de certaines maladies animales en Europe (e.g. besnoitiose bovine) a mis en avant leur rôle de vecteur mécanique. Cependant, la richesse biologique et la vulnérabilité des milieux pastoraux impliquent de réduire l’usage des insecticides contre les ectoparasites. Nous avons donc cherché à mieux connaître l’activité des taons dans les estives et àréfléchir à des méthodes de contrôle pratiques, efficaces et sélectives. Les pièges attractifs ou les répulsifs utilisables dans une stratégie « push-pull » impliquant de bien connaître l’olfaction des espèces cibles, nous nous sommes intéressés à la physiologie olfactive des taons et aux composés chimiques qui modulent les interactions avec leurs hôtes.Les travaux sur l’écologie des taons dans les Pyrénées ont montré que l’exposition, l’altitude et la structure paysagère influençaient leur distribution spatio-temporelle, et que les conditions climatiques influençaient l’activité de piqûre des femelles. De plus, le caractère trophique opportuniste des femelles a été confirmé et le cerf est apparu comme un hôte de choix. Les réponses physiologiques et comportementales de Tabanus bromius et d’Atylotus quadrifarius aux odeurs d’urines et de leurs constituants ont révélé des différences de sensibilité olfactive entre ces deux espèces, la forte attractivité de l’urine de cheval s’expliquant probablement par la présence de composés volatiles qui agiraient en synergie. Pour conclure, nous proposons pour les troupeaux en estives des mesures de protection contre les taons et des perspectives de recherche pour ce groupe. / Mediterranean pastoral areas are favourable to the diversity and abundance of Tabanidae. On the other hand, their role as mechanical vectors was highlighted by the re-emergence of animal diseases in Europe (e.g. Bovine Besnoitiosis). However, the biological richness and vulnerability of pastoral communities involve reducing the use of insecticides against ectoparasites. The objectives of this thesis were to better understand the activity of horse flies in summer pastures and to consider practical, efficient and selective pest control methods. A “push-pull” strategy using attractive traps and/or repellents implies a good knowledge of insect olfaction. Therefore, it was interesting to study the olfactory sensitivity of horse flies and semiochemicals that affect vector-host interactions. In the Pyrenean mountains, work on the ecology of horseflies showed that their spatiotemporal distribution was influenced by exposure, altitude and landscape structure, and that the biting activity of females was related to climatic conditions. Moreover, the opportunistic feeding pattern of tabanids was confirmed with a preference for red deer. The physiological and behavioural responses of Tabanus bromius and Atylotus quadrifarius to urines volatiles and their constituents revealed differences between the olfactory sensitivity of these two species. The high attractiveness of aged horse urine is likely to be due to the mixture of various active compoundsthat may act synergistically. To conclude, pest control methods to protect cattle against horse flies in summer pastures and new research opportunities are discussed.

Les crevettes Alvinocarididae sont emblématiques des sources hydrothermales de la Dorsale Médio-Atlantique, mais les mécanismes qui leur permettent de détecter leur habitat sont énigmatiques. Il est supposé que les signatures chimique et thermique du fluide hydrothermal leur servent de repères pour s’orienter. Les facultés chimio- et thermosensorielles de l’espèce hydrothermale Mirocaris fortunata et de l’espèce côtière Palaemon elegans ont été étudiées avec plusieurs approches. Des traits structuraux du système sensoriel périphérique et central ont été comparés pour inférer sur les facultés olfactives de chaque espèce. L’expression du récepteur ionotropique IR25a dans les organes chimiosensoriels a été mesurée. Une technique d’électroantennographie a été mise au point afin de tester la détection de composés chimiques de fluide hydrothermal par les crevettes. Plusieurs expériences à pression atmosphérique et in situ ont été réalisées afin d’étudier le comportement des espèces hydrothermale et côtière exposées à une odeur de nourriture, du sulfure ou des températures relativement chaudes. L’ensemble des résultats montre que M. fortunata présente un système chimio- et thermosensoriel fonctionnel et apporte des bases substantielles pour approfondir les connaissances sur les adaptations sensorielles en milieu hydrothermal profond. / Alvinocaridid shrimp are an emblematic taxon at hydrothermal vents on the Mid-Atlantic Ridge, but how they locate active vents and detect their habitat is still enigmatic. They might use the chemical and thermal signatures of the hydrothermal fluid as orientation cues. The chemo- and thermosensory abilities of the hydrothermal species Mirocaris fortunata and the coastal species Palaemon elegans were investigated using various approaches. Structural features of the peripheral and central nervous system were used as rough estimates of their olfactory abilities. The co-ionotropic receptor IR25a, involved in chemodetection, was identified and located in the antennal appendages. A new electroantennography method was developed to test the detection of hydrothermal fluid chemicals. Several attraction tests were conducted at atmospheric and in situ pressure to investigate the behavior of the vent and shallow-water species when exposed to a food odor, sulfide and warm temperatures. Altogether, these results provide advances in the knowledge of the chemosensory biology of vent shrimp, and a substantial background for future researches on sensory adaptations to the hydrothermal environment.