L’existence de conflits est une caractéristique inhérente aux sociétés animales dont la structure génétique est non clonale. L’objectif principal de cette thèse était d’étudier les décisions reproductives individuelles des ouvrières en lien avec la dynamique coopération/conflit dans les sociétés annuelles du bourdon Bombus terrestris. Les colonies de B. terrestris présentent la particularité de se développer selon deux phases distinctes : une phase sociale caractérisée par une coopération altruiste des ouvrières et une phase de compétition durant laquelle les ouvrières entrent en conflit entre elles et avec la reine pour la production des mâles. L’analyse détaillée du comportement de dérive en conditions semi-naturelles a permis de démontrer l’existence d’une stratégie de reproduction supplémentaire pour les ouvrières ; quand le conflit s’exprime, certaines ouvrières fertiles quittent leur nid pour se reproduire dans les colonies voisines de la même espèce. Cette stratégie alternative de reproduction permet aux ouvrières d’éviter l’inhibition reproductive au sein de leur nid et d’optimiser ainsi leur inclusive fitness. Nos études ont de plus révélé que les ouvrières ajustent de façon adaptée leur comportement reproducteur à l’environnement social. La grande plasticité reproductive des ouvrières repose sur leur capacité à détecter et à traiter de multiples informations pertinentes de leur environnement social. Enfin, les résultats de cette thèse suggèrent l’existence d’une stratégie de défense coloniale contre le parasitisme reproductif des ouvrières. De part leur signature chimique spécifique, les parasites potentiels sont reconnus et discriminés comportementalement à l‘entrée du nid par les gardes. Cette pluralité de stratégie de reproduction à la disposition des ouvrières est marginale au sein des hyménoptères sociaux, et les résultats obtenus de ce travail nous conduisent à discuter les traits d’histoire de vie de B. terrestris qui ont pu favoriser leur évolution. / Conflicts are inherent characteristics of non-clonal animal societies. The main goal of this thesis was to study the individual reproductive decisions of workers in relation with the cooperation/conflict dynamics in the annual bumblebee Bombus terretris. Colonies of B. terretris have the particularity to go through two distinct phases : a social phase characterized by an altruistic cooperation from workers and a competition phase during which the queen and workers compete for the production of males. The study of worker's behaviour in semi-natural conditions allowed to demonstrate the existence of an additional reproductive strategy for workers ; when the conflict is expressed, some fertile workers leave their nest to reproduce in neighbouring colonies of the same species. This alternative reproductive strategy allows workers to avoid reproductive inhibition in their nest and thus to optimize their inclusive fitness. Workers also adjust their reproductive behaviour to their social environment, in line with their reproductive interests. This high reproductive plasticity of workers relies on their ability to detect and process the multiple relevant signals of their social environment. Finally, the results of this thesis suggest the existence of a colonial defence strategy against worker reproductive parasitism. By their specific chemical signature, potential parasites are recognized and behaviourlly discriminated by guards at the nest-entrance. The multiple reproductive strategies of bumble bee workers appear marginal in social Hymenoptera, and the life history traits of B. terretris which could have promoted this diversification are discussed.

A Filogeografia é um dos campos mais multidisciplinares da Biologia, e agrega diferentes áreas como sistemática filogenética, genética de populações, geologia, modelos paleogeográficos e paleoclimáticos, demografia e conservação. Assim, além da Filogeografia comparada, apresento resultados importantes para a conservação das espécies estudadas e a descrição de uma espécie críptica. Bombus morio e B. pauloensis são espécies simpátricas que ocupam uma grande área em dois importantes biomas brasileiros, Mata Atlântica e Cerrado. Exceto pelas diferenças na dispersão, maior em B. morio, possuem comportamento e nicho ecológico semelhantes. Os resultados gerados a partir de marcadores moleculares e modelagem de distribuição sugerem que as alterações climáticas do final do Pleistoceno influenciaram a estrutura populacional das duas espécies, e que a maior capacidade de dispersão foi responsável pela ausência de estruturação em B. morio. O leste do estado de São Paulo, no qual foram encontradas diferentes quebras filogeográficas para vários organismos, mostrou-se mais uma vez complexo e com mais um diferente cenário filogeográfico. Além disso, essa região por ser o centro da diversidade genética em B. pauloensis e ter sido estável ao longo da mudanças climáticas para ambas espécies, é prioritária para a conservação das mesmas / Phylogeography is one of the most multidisciplinary fields in Biology and joins different areas such as phylogenetic systematics, population genetics, geology, paleogeographic and paleoclimatic models, demography, and conservation. Thus, besides comparative Phylogeography, I also present important results concerning the conservation of the species studied and the description of a cryptic species. Bombus morio and B. pauloensis are sympatric species, occupying a large area in two important Brazilian biomes, Atlantic forest and Brazilian savanna. Except for differences in dispersal, which is greater in B. morio, both species have similar behavior and ecological niches. The results obtained by molecular data and distribution models suggest that climatic oscillations in the late Pleistocene influenced the population structure of both species, and that a greater dispersal capacity was responsible for the absence of genetic structure in B. morio. Eastern São Paulo state, in which different phylogeographic breaks have been found for many organisms, seems to be complex and to have a new phylogeographic scenario. Furthermore, this region, because it is the center of genetic diversity for B. pauloensis and it was stable throughout periods of climatic change for both species, is a priority for their conservation

The pollination of greenhouse sweet pepper (Capsicum annuum L. var. grossum cv. Superset) by Bombus impatiens Cr. was investigated in Ste. Scholastique, Quebec for two periods, 27 June-15 July and 4-18 August, 1995 to determine the pollination effectiveness of B. impatiens compared to a mechanical method (vibration wand) and natural greenhouse ventilation (NGV) and to determine the foraging activity of B. impatiens throughout the pollination period. B. impatiens pollination resulted in a significantly greater number of seeds per fruit and a greater percent marketable fruit, due to a positive quadratic relationship between seed number and fruit weight, than both vibration wand and NGV. Both B. impatiens and NGV resulted in a significantly greater fruit set than vibration wand. Per fruit, an extra profit of $0.06 for green and $0.13 for red sweet peppers could be made by B. impatiens pollination over NGV, due to greater marketable fruit and greater mean fruit weight. B. impatiens pollination was more effective than both vibration wand and NGV even though both the daily activity of the insect at the hive (hive traffic) and their foraging on plants (greenhouse foraging) decreased throughout the pollination period and attained a maximum of only 3 B. impatiens foraging in the greenhouse during the second period. It was estimated that a B. impatiens colony of 30-40 workers could optimally pollinate 17475 plants or a greenhouse size of about 9470 m$ sp2.$

Parasites and other associates can play an important role in shaping the communities of their hosts; and their hosts, in turn, shape the community of host-associated organisms. This makes the study of associates vital to understanding the communities of their hosts. Mites associated with bees have a range of lifestyles on their hosts, acting as anything from parasitic disease vectors to harmless scavengers to mutualistic hive cleaners. For instance, in Apis mellifera (the European honey bee) the parasitic mite Varroa destructor has had a dramatic impact as one of the causes of colony-collapse disorder. However, little is known about mites associated with bees outside the genus Apis or about factors influencing the makeup of bee-associated mite communities. In this thesis, I explore the mite community of bees of the genus Bombus and how it is shaped by extrinsic and intrinsic aspects of the bees' environment at the individual bee, bee species, and bee community levels. Bombus were collected from 15 sites in the Ottawa area along a land-use gradient and examined for mites. The number of individual mites and number of mite species hosted by particular bee species increased significantly with bee species abundance. In addition, several bee species differed in terms of mite abundance, mite species richness, mite prevalence, and mite diversity at the level of individual bees and at the species level. In particular, individuals of rare bee species tended to have particularly high mite abundance in comparison to other bees. However, geography, site quality, and bee diversity were never significant predictors of mite community attributes at any level of analysis. Overall, the best predictor of bee-mite community attributes is the bee species themselves. Thus, these mite communities were not shaped by the factors that are known to shape the parasite communities of other species (i.e., geographic distance, host diversity), perhaps because of the commensalistic nature of most of the mite species investigated here. These findings have implications for conservation of bumble bees, given that commensals may become cleptoparasitic at high densities and may act as disease vectors.

A Filogeografia é um dos campos mais multidisciplinares da Biologia, e agrega diferentes áreas como sistemática filogenética, genética de populações, geologia, modelos paleogeográficos e paleoclimáticos, demografia e conservação. Assim, além da Filogeografia comparada, apresento resultados importantes para a conservação das espécies estudadas e a descrição de uma espécie críptica. Bombus morio e B. pauloensis são espécies simpátricas que ocupam uma grande área em dois importantes biomas brasileiros, Mata Atlântica e Cerrado. Exceto pelas diferenças na dispersão, maior em B. morio, possuem comportamento e nicho ecológico semelhantes. Os resultados gerados a partir de marcadores moleculares e modelagem de distribuição sugerem que as alterações climáticas do final do Pleistoceno influenciaram a estrutura populacional das duas espécies, e que a maior capacidade de dispersão foi responsável pela ausência de estruturação em B. morio. O leste do estado de São Paulo, no qual foram encontradas diferentes quebras filogeográficas para vários organismos, mostrou-se mais uma vez complexo e com mais um diferente cenário filogeográfico. Além disso, essa região por ser o centro da diversidade genética em B. pauloensis e ter sido estável ao longo da mudanças climáticas para ambas espécies, é prioritária para a conservação das mesmas / Phylogeography is one of the most multidisciplinary fields in Biology and joins different areas such as phylogenetic systematics, population genetics, geology, paleogeographic and paleoclimatic models, demography, and conservation. Thus, besides comparative Phylogeography, I also present important results concerning the conservation of the species studied and the description of a cryptic species. Bombus morio and B. pauloensis are sympatric species, occupying a large area in two important Brazilian biomes, Atlantic forest and Brazilian savanna. Except for differences in dispersal, which is greater in B. morio, both species have similar behavior and ecological niches. The results obtained by molecular data and distribution models suggest that climatic oscillations in the late Pleistocene influenced the population structure of both species, and that a greater dispersal capacity was responsible for the absence of genetic structure in B. morio. Eastern São Paulo state, in which different phylogeographic breaks have been found for many organisms, seems to be complex and to have a new phylogeographic scenario. Furthermore, this region, because it is the center of genetic diversity for B. pauloensis and it was stable throughout periods of climatic change for both species, is a priority for their conservation

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Made available in DSpace on 2015-03-26T13:30:18Z (GMT). No. of bitstreams: 1 texto completo.pdf: 1810618 bytes, checksum: a2820c4a14922212729ca26b59052d7f (MD5) Previous issue date: 2008-02-29 / The genus Bombus in the entire world it has an ecological and economic importance; these bees are being used as pollinators of many cultures as tomatoe, pumpkin, strawberry among others. But the fact of that these bees have some levels of aggressiveness, they make that its nests are destroyed leading to the extinguishing risk. Many works already had been developed for the knowledge of the biology of this group. The objective of this study was to study some aspects of the establishment of colonies in captivity conditions and of the reproductive biology of B. morio and B. atratus. Some methods of induce of oviposition of queens of the two species had been made. Males of different ages of B. atratus had been dissected and the age of sexual maturation was determined. Also some aspects in the reproduction and activation of the ovaries of queens in absence of mating of B. morio had been studied, through the histology and histochemistry tests. The results had contributed for the common knowledge of the rearing in captivity and the reproductive biology of the studied species. It was determined that the introduction of immature, of workers or a queen sister (in these species), induce the queens to star oviposition. Of the 110 tested queens, 80% had star oviposition and produced immature. Only two queens (B. atratus) obtained to produce adults (males). Males of B. atratus from the seventh day of life, the testicles were total reduced and the seminal vesicles are full of spermatozoa, showing that in this age is sexually mature. This suggests that in the attempts of mating in laboratory, male of this age should be used. In the case of the queens, the study of behaviour of queens and ovarian development showed that its ovaries are active from five days after the emergency thus remaining for until more than 30 days. This suggests that for attempts of mating in laboratory, queens of 10 days up to 40 days of age should be used. The results of the observation of nests and start colonies from queens, showed that queens of these species have a long time of activation of its ovaries (more of 30 days) and as consequence of this, the queens can remain more time in the nests and to star oviposition without mating. The presence of immature or individuals of the same specie or the other species the same genus makes that it accelerate the process of start oviposition. It is necessary to make studies related the alimentary diets to guarantee the continuity in the produced colonies and of the queens that start oviposition in the laboratory. / No mundo inteiro o gênero Bombus tem uma importância ecológica e econômica, uma vez que estas abelhas são polinizadores de muitas culturas como tomate, abóbora, morango entre outras. O fato de que estas abelhas serem de uma forma geral agressivas, faz com que seus ninhos sejam destruídos levando ao risco de extinção. Muitos trabalhos já foram desenvolvidos para o conhecimento da biologia desse grupo. O objetivo deste estudo foi estudar alguns aspectos do estabelecimento de colônias em condições de cativeiro e da biologia reprodutiva de B. morio e B. atratus. Foram feitos vários métodos de iniciação de postura das rainhas das duas espécies. Machos de diferentes idades de B. atratus foram dissecados e a idade de maturação sexual foi determinada. Também foram estudados alguns aspectos na reprodução e ativação dos ovários de rainhas de B. morio em ausência de cópula, através da histologia e testes histoquímicos. Os resultados contribuíram para o conhecimento geral da criação em cativeiro e da biologia reprodutiva das espécies estudadas. Determinou-se que a introdução seja de imaturos, de operárias ou de uma rainha irmã (nas duas espécies), induzem as rainhas a iniciarem postura. Das 110 rainhas testadas, 80% iniciaram postura e produziram imaturos. Apenas duas rainhas (B. atratus) conseguiram produzir adultos (machos). Machos de B. atratus a partir do sétimo dia de vida os testículos estavam regredidos e as vesículas seminais totalmente cheias de espermatozóides, mostrando que nesta esta idade já se estão sexualmente maduros. Sugere-se que nas tentativas de acasalamento em laboratório sejam utilizados machos dessa idade. No caso das rainhas, o estudo do comportamento e do desenvolvimento ovariano mostrou que seus ovários são ativos a partir de cinco dias após a emergência permanecendo assim por até mais de 30 dias. Sugere-se que para tentativas de acasalamento em laboratório sejam utilizadas rainhas de 10 dias até 40 dias de idade. Os resultados tanto da parte de acompanhamento dos ninhos e iniciação de colônias a partir de rainhas quanto dos estudos histológicos nos mostram que as rainhas destas espécies têm um tempo longo de ativação de seus ovários (+ de 30 dias) e como conseqüência disto as rainhas podem permanecer mais tempo nos ninhos e iniciar a postura sem ter copulado antes. A presença de indivíduos ou imaturos das mesmas ou outras espécies faz que acelere o processo de inicio de postura. É necessário fazer estudos aprofundando relacionados a dietas alimentares para garantir a continuidade nas colônias produzidas e das rainhas que iniciam postura no laboratório.

The decline of bumblebee (Bombus spp.) populations in the UK and worldwide has been well reported. It has been generally assumed that such declines result in the genetic impoverishment of some species, potentially leading to reduced fitness and increased extinction risk. This study tested the fundamental assumption linking population fragmentation with fitness, in a model system of two Bombus species native to the UK. Bombus monticola has declined significantly in range across the UK in recent years and occupies fragmented upland areas, while Bombus pratorum has remained abundant and widespread over many habitat types. The effects of genetic diversity on fitness have been addressed in wild Bombus species, but this is the first study to explicitly compare data from species of differing levels of population connectivity and hence test the assumptions of traditional population genetic theory. As genetic diversity has often been linked with immunocompetence, aspects of the innate immune response were quantified, together with parasite load. These empirical measures of fitness showed lower than expected variability between the two study species, and no evidence was found to support the theory of lower fitness in fragmented populations. However, the considerable variability between sample sites in both species for all parameters measured raised interesting questions as to the underlying evolutionary processes; it is postulated that B. monticola populations may maintain a higher than expected Ne, despite their fragmented distribution. This study also provided methodological developments. An alternative method for the quantification of wing wear as a proxy for age was proposed, which could be easily applied to other Bombus species and possibly adapted for use in other flying insects. In addition possible sources of error in AFLP analysis were highlighted which have not been adequately discussed in the current literature, namely the effects of sample storage. Given the utility of AFLPs for non-model species, this is an important avenue for future research, and would be applicable to studies in other systems. Overall, the data presented here emphasise the challenges of studying fitness in wild populations, and underline the requirement for research into the fundamental principles underlying many assumptions made by conservation genetic theory.

Poster exhibited at GPSC Student Showcase, February 24th, 2016, University of Arizona. / We investigated whether bees have an innate preference for flowers with saturated pigments and whether experience altered any preference. Preference could be a result of reward quality varying by color morph and/or responses to the petals, anthers, or their combination. Consequently, we gave bees experience on one of four floral configurations created from two color morphs of Solanum tridynanum. We subsequently tested learned preference using an array of all four configurations. Changes in preference as a result of experience were not mediated by anthers, only by petals. Bees that first experienced configurations with purple petals subsequently preferred configurations with purple petals, relative to naïve bees. However, bees that first experienced white petals showed no subsequent change in preference relative to naïve bees. Surprisingly, naïve bees showed no preference for any particular floral configuration. Rather than an innate preference for flowers with more saturated colors, bees are less able to develop a preference for unsaturated types. Because individuals are more able to develop a preference for saturated flowers, these flowers experience greater visitation, and thus greater pollination success, over unsaturated types.

Many bumblebee species are suffering from the effects of habitat fragmentation and population isolation. In some cases, populations have lost genetic diversity due to genetic drift and it is possible they are now at heightened risk of extinction. Inbreeding may be particularly costly to bumblebees because, as Hymenoptera, their complementary sex determination system can lead to the production of sterile or inviable diploid males. However, little is known about the effect that diploid male production has on bumblebee colony fitness. Here, the consequences of brother-sister mating in the bumblebee Bombus terrestris are investigated, and the production of diploid males was found to exert considerable costs at the colony level by reducing productivity and survival. Diploid males may therefore act as indicators of the genetic health of populations, and their detection could be used as an informative tool in hymenopteran conservation. Due to the costs associated with inbreeding, selection may have favoured the evolution of kin recognition systems in bumblebees. Data are presented that suggest that B. terrestris can discriminate between kin and non-kin as gynes were less willing to mate with siblings compared to non-relatives. Theory predicts that inbreeding may impose further costs on bumblebees through increased levels of parasitism, but empirical data are scarce. The relationship between population genetic diversity and parasite prevalence is assessed using Hebridean island populations of Bombus muscorum and Bombus jonellus. In the more outbred B. jonellus, there was no relationship between parasite prevalence and population heterozygosity. But prevalence of the gut parasite Crithidia bombi and the tracheal mite Locustacarus buchneri were found to be higher in populations of B. muscorum that had lower genetic diversity. In addition to assessing infection status, the activity of the immune system was assessed in each individual bee. However, there was no relationship between population heterozygosity and these immune parameters. This suggests that, in some Hymenopteran species, as populations lose genetic diversity the impact of parasitism will increase, potentially pushing threatened populations closer to extinction. Therefore, preventing population fragmentation by the creation of suitable habitats and by ensuring connectivity between habitat patches are important aspects of hymenopteran conservation. Finally, this thesis investigates the potential threat of pathogen spread from commercially reared bumblebees used for crop pollination to wild bumblebees. Although no direct evidence for parasite spillover is found, the prevalence of C. bombi was significantly higher in B. terrestris by the end of the season on farms that used commercial bumblebees compared to farms that did not. This high prevalence does suggest that pathogen spillover is a potential threat and it would be preferable to reduce the usage of commercial bumblebees where possible. For example, sowing wild flower mixes could boost natural pollinator populations, which in turn would benefit soft fruit pollination. Overall, this thesis contributes to our knowledge of the consequences of inbreeding in bumblebees and the relationship between genetic diversity and parasite prevalence. It provides a greater understanding of the factors that might be pushing threatened pollinators towards extinction and as a whole provides important information that may inform conservation practitioners, whose aim is to protect the future of our hymenopteran pollinators.