Submitted by Renata Lopes (renatasil82@gmail.com) on 2016-10-07T13:25:21Z No. of bitstreams: 1 mateusaparecidoclemente.pdf: 1478213 bytes, checksum: c23d979793df401efab60284dd39526f (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2016-10-11T15:27:36Z (GMT) No. of bitstreams: 1 mateusaparecidoclemente.pdf: 1478213 bytes, checksum: c23d979793df401efab60284dd39526f (MD5) / Made available in DSpace on 2016-10-11T15:27:36Z (GMT). No. of bitstreams: 1 mateusaparecidoclemente.pdf: 1478213 bytes, checksum: c23d979793df401efab60284dd39526f (MD5) Previous issue date: 2009 / Em Minas Gerais as áreas de Mata Atlântica, Campo Rupestre e Mata Ciliar destacam-se devido sua relevância para a Biologia da Conservação com expressiva diversidade, incluindo a de vespas sociais. Este grupo de insetos, que no Brasil está representado pelos Polistinae, causa considerável impacto nos ecossistemas, já que as vespas são importantes predadoras e visitantes florais. Este trabalho teve como objetivo estudar a estrutura e composição da taxocenose de vespas sociais durante os períodos quente/úmido e frio/seco e verificar a eficiência dos métodos de coleta utilizados na captura desses insetos no Parque Estadual do Ibitipoca. Também foi estimada a riqueza, diversidade, abundância, amplitude do nicho e a equitatividade de vespas sociais visitantes em flores deste local. Foram realizadas 12 coletas em três fitofisionomias (Campo Rupestre, Mata Ciliar e um fragmento de Mata Atlântica) no período de novembro de 2007 a outubro de 2008. Usou-se três metodologias de coleta: busca ativa com auxílio de uma rede entomológica; busca pontual onde eram vistoriadas plantas em floração com vespas visitantes e armadilhas com suco de maracujá ou caldo de sardinha. Foram coletados 926 indivíduos de vespas sociais distribuídos em 21 espécies e oito gêneros sendo para a busca ativa (18 espécies), busca pontual (15 espécies), armadilha atrativa de suco de maracujá (sete espécies) e caldo de sardinha (cinco espécies). A Mata Ciliar apresentou a maior riqueza de espécies (19), seguida pelo Campo Rupestre (14) e Mata Atlântica (5), porém o Campo Rupestre apresentou a maior diversidade (H’= 2,16) em relação à Mata Ciliar (H’= 1,43) e Mata Atlântica (H’= 0,18), O cálculo da constância das espécies demonstrou que 38,08 % foram acidentais (C<25%), 38,08% acessórias (25% <C< 50%) e 23,84% constantes (C>50%). Nos períodos frio/seco e quente/úmido, para as três áreas estudas o teste de Spearman demonstrou que não houve correlação significativa da riqueza e abundância com as variáveis temperatura e pluviosidade. Foram coletados 103 indivíduos pertencentes a 15 espécies e sete gêneros visitando flores de 27 espécies de plantas (14 famílias). As famílias mais visitadas foram Erythroxylaceae (10 espécies) e Asteraceae (10 espécies) que também se destacou com a maior abundância de indivíduos (55). Mischocyttarus confusus, Mischocyttarus drewseni e Polybia sp2 foram as mais abundantes na Mata Ciliar e para o Campo Rupestre foi Polybia sp2. A diversidade de vespas sociais em flores na Mata Ciliar (H’= 0,78 e J’= 0,75) foi maior que no campo Rupestre (H’= 0.30 e J’= 0,39) e não houve diferenças significativas entre os índices de Shannon-Wiener para os dois locais estudados (Z(U) = 1.8475 (p) =0.0647. A amplitude do nicho trófico apresentou uma variação de 0,63 a 10 2,42 sendo M. drewseni visitante em 12 das 27 espécies de plantas do Parque Estadual do Ibitipoca registradas no período de estudo alcançando o maior valor da amplitude do nicho (2,42) e Polybia sp2, que visitou nove das 27 espécies vegetais apresentando maior abundância durante o período de coleta. Conclui-se que nenhuma das metodologias de amostragem capturou todas as espécies registradas no presente estudo, sendo o mais indicado a utilização destas em consórcio e a riqueza e diversidade variaram de acordo com as características fitofisionomicas de cada área, disponibilizando recursos e locais de nidificação. As vespas atuaram como visitantes regulares em flores do presente estudo, indicando a importância destes insetos na busca por néctar em diferentes flores do Parque Estadual do Ibitipoca / In Minas Gerais, areas of the Atlantic Forest, Rupestre fields and the Riparian Forest have been highlighted due to their importance for Conservation Biology, presenting high diversity and including social wasps. This group of insects, which is represented by Polistinae in Brazil, causes considerably high damage on ecosystems, since they are important predators and floral visitors. The objective of this work was to study the structure and taxocenosis composition of social wasps during the hot/humid and cold/dry seasons, and to observe the efficiency of the collection methods used to capture these insects at Ibitipoca State Park. The work also estimated richness, diversity, abundance, niche amplitude and evenness of the flower-visiting social wasps. In three phytophysiognomies (Rupestre fields, the Riparian Forest and an Atlantic Forest fragment), 12 collections were carried out from November 2007 to October 2008. Three collection methods were used: the active search, with the aid of an entomological net; the punctual method, with plants in the flowering periods being visited by wasps, and attractive traps with passion fruit juice or broth of sardines (sardines preserved and water). A total of 926 social wasp individuals were collected, and distributed among 21 species and eight genera in the active search (18 species), in the punctual method (15 species), in traps with passion fruit juice (seven species) and sardines (five species). The Riparian Forest presented the highest species richness (19), followed by Rupestre fields (14) and the Atlantic Forest (5), though Rupestre fields showed higher diversity (H’= 2.16) than the Riparian Forest (H’= 1.43) and the Atlantic Forest (H’= 0.18). The regular rate calculation of the species showed that 38.08 % were accidental (C<25%), 38.08% accessories (25% <C< 50%), and 23.84% constant (C>50%). In the cold/dry and hot/humid seasons, considering the three areas of study, the Spearman test showed that there was no significant correlation between richness and abundance and the climatic variables temperature and pluviosity. A total of 103 individuals were obtained, belonging to 15 species and seven genera, visiting flowers of 27 species of plants (14 families). The families with the highest number of visitors were Erythroxylaceae (10 species) and Asteraceae (10 species), which also stood out with the highest values for abundance of individuals (55). Mischocyttarus confusus, Mischocyttarus drewseni and Polybia sp2 were the most abundant in the Riparian Forest, and Polybia sp2 in Rupestre fields. The diversity of flower-visiting social wasps in the Riparian Forest (H’= 0.78 and J’= 0.75) was higher than in Rupestre fields (H’= 0.30 and J’= 0.39), and there were no significant differences between the Shannon-Wiener indices for the two locations studied 12 (Z(U)= 1.84 (p)= 0.064. The amplitude index of trophic niche showed variations from 0.63 to 2.42, with M. drewseni visitors present in 12 among the 27 species of plants at Ibitipoca State Park, being recorded during the study period with the highest amplitude index of trophic niche (2,42) Polybia sp2 visited nine of the 27 vegetable species, and showed higher abundance during the collection period. It may be concluded that no sampling method alone captured all the species recorded in the present study, a fact that indicates the use of all methods combined. In addition, richness and diversity varied according to phytophysiognomic characteristics of each location, with available resources and places for nidification. Wasps were regular floral visitors in the present study, showing the importance of these insects in search of nectar in different flowers at Ibitipoca State Park.

Doctor of Philosophy (PhD) / A renewed focus on generalised pollinator systems has inspired a conceptual framework which highlights that spatial and temporal interactions among plants and their assemblage of pollinators can vary across the individual, population, regional and species levels. Pollination is clearly a dynamic interaction, varying in the number and interdependence of participants and the strength of the outcome of the interaction. Therefore, the role of variation in pollination is fundamental for understanding ecological dynamics of plant populations and is a major factor in the evolution and maintenance of generalised and specialised pollination systems. My study centred on these basic concepts by addressing the following questions: (1) How variable are pollinators in a generalised pollination system? To what degree do insect visitation rates and assemblage composition vary spatially among populations and temporally among flowering seasons? (2) How does variation in pollinators affect plant reproductive success? I chose to do this using a model system, Trachymene incisa subsp. incisa (Apiaceae), which is a widespread Australian herbaceous species with simple white flowers grouped into umbels that attract a high diversity of insect visitors. The Apiaceae are considered to be highly generalist in terms of pollination, due to their simple and uniform floral display and easily accessible floral rewards. Three populations of T. incisa located between 70 km and 210 km apart were studied over 2-3 years. The few studies investigating spatial and temporal variation simultaneously over geographic and yearly/seasonal scales indicate that there is a trend for more spatial than temporal variation in pollinators of generalist-pollinated plants. My study showed both spatial and temporal variation in assemblage composition among all populations and variation in insect visitation rates, in the form of a significant population by year interaction. However, removing ants from the analyses to restrict the assemblage to flying insects and the most likely pollinators, resulted in a significant difference in overall visitation rate between years but no difference in assemblage composition between the Myall Lakes and Tomago populations. These results indicate more temporal than spatial variation in the flying insect visitor assemblage of T. incisa. Foraging behaviour provides another source of variation in plant-pollinator interactions. Trachymene incisa exhibits umbels that function as either male or female at any one time and offer different floral rewards in each phase. For successful pollination, pollinators must visit both male and female umbels during a foraging trip. Insects showed both preferences and non-preferences for umbel phases in natural patches where the gender ratio was male biased. In contrast, insects showed no bias in visitation during a foraging trip or in time spent foraging on male and female umbels in experimental arrays where the gender ratio was equal. Pollinator assemblages consisting of a mixture of different pollinator types coupled with temporal variation in the assemblages of populations among years maintains generalisation at the population/local level. In addition, spatial variation in assemblages among populations maintains generalisation at the species level. Fire alters pollination in T. incisa by shifting the flowering season and reducing the abundance of flying insects. Therefore, fire plays an important role in maintaining spatial and temporal variation in this fire-prone system. Although insect pollinators are important in determining the mating opportunities of 90% of flowering plant species worldwide, few studies have looked at the effects of variation in pollinator assemblages on plant reproductive success and mating. In T. incisa, high insect visitation rates do not guarantee high plant reproductive success, indicating that the quality of visit is more important than the rate of visitation. This is shown by comparing the Agnes Banks and Myall Lakes populations in 2003: Agnes Banks received the highest visitation rate from an assemblage dominated by ants but produced the lowest reproductive output, and Myall Lakes received the lowest visitation rate by an assemblage dominated by a native bee and produced the highest seedling emergence. Interestingly, populations with different assemblage composition can produce similar percentage seed set per umbel. However, similar percentage seed set did not result in similar percentage seedling emergence. Differences among years in reproductive output (total seed production) were due to differences in umbel production (reproductive effort) and proportion of umbels with seeds, and not seed set per umbel. Trachymene incisa is self-compatible and suffers weak to intermediate levels of inbreeding depression through early stages of the life cycle when seeds are self-pollinated and biparentally inbred. Floral phenology, in the form of synchronous protandry, plays an important role in avoiding self-pollination within umbels and reducing the chance of geitonogamous pollination between umbels on the same plant. Although pollinators can increase the rate of inbreeding in T. incisa by foraging on both male and female phase umbels on the same plant or closely related plants, most consecutive insect movements were between plants not located adjacent to each other. This indicates that inbreeding is mostly avoided and that T. incisa is a predominantly outcrossing species, although further genetic analyses are required to confirm this hypothesis. A new conceptual understanding has emerged from the key empirical results in the study of this model generalised pollination system. The large differences among populations and between years indicate that populations are not equally serviced by pollinators and are not equally generalist. Insect visitation rates varied significantly throughout the day, highlighting that sampling of pollinators at one time will result in an inaccurate estimate and usually underestimate the degree of generalisation. The visitor assemblage is not equivalent to the pollinator assemblage, although non-pollinating floral visitors are likely to influence the overall effectiveness of the pollinator assemblage. Given the high degree of variation in both the number of pollinator species and number of pollinator types, I have constructed a model which includes the degree of ecological and functional specialisation of a plant species on pollinators and the variation encountered across different levels of plant organisation. This model describes the ecological or current state of plant species and their pollinators, as well as presenting the patterns of generalisation across a range of populations, which is critical for understanding the evolution and maintenance of the system. In-depth examination of pollination systems is required in order to understand the range of strategies utilised by plants and their pollinators, and I advocate a complete floral visitor assemblage approach to future studies in pollination ecology. In particular, future studies should focus on the role of introduced pollinators in altering generalised plant-pollinator systems and the contribution of non-pollinating floral visitors to pollinator assemblage effectiveness. Comparative studies involving plants with highly conserved floral displays, such as those in the genus Trachymene and in the Apiaceae, will be useful for investigating the dynamics of generalised pollination systems across a range of widespread and restricted species.

Doctor of Philosophy (PhD) / A renewed focus on generalised pollinator systems has inspired a conceptual framework which highlights that spatial and temporal interactions among plants and their assemblage of pollinators can vary across the individual, population, regional and species levels. Pollination is clearly a dynamic interaction, varying in the number and interdependence of participants and the strength of the outcome of the interaction. Therefore, the role of variation in pollination is fundamental for understanding ecological dynamics of plant populations and is a major factor in the evolution and maintenance of generalised and specialised pollination systems. My study centred on these basic concepts by addressing the following questions: (1) How variable are pollinators in a generalised pollination system? To what degree do insect visitation rates and assemblage composition vary spatially among populations and temporally among flowering seasons? (2) How does variation in pollinators affect plant reproductive success? I chose to do this using a model system, Trachymene incisa subsp. incisa (Apiaceae), which is a widespread Australian herbaceous species with simple white flowers grouped into umbels that attract a high diversity of insect visitors. The Apiaceae are considered to be highly generalist in terms of pollination, due to their simple and uniform floral display and easily accessible floral rewards. Three populations of T. incisa located between 70 km and 210 km apart were studied over 2-3 years. The few studies investigating spatial and temporal variation simultaneously over geographic and yearly/seasonal scales indicate that there is a trend for more spatial than temporal variation in pollinators of generalist-pollinated plants. My study showed both spatial and temporal variation in assemblage composition among all populations and variation in insect visitation rates, in the form of a significant population by year interaction. However, removing ants from the analyses to restrict the assemblage to flying insects and the most likely pollinators, resulted in a significant difference in overall visitation rate between years but no difference in assemblage composition between the Myall Lakes and Tomago populations. These results indicate more temporal than spatial variation in the flying insect visitor assemblage of T. incisa. Foraging behaviour provides another source of variation in plant-pollinator interactions. Trachymene incisa exhibits umbels that function as either male or female at any one time and offer different floral rewards in each phase. For successful pollination, pollinators must visit both male and female umbels during a foraging trip. Insects showed both preferences and non-preferences for umbel phases in natural patches where the gender ratio was male biased. In contrast, insects showed no bias in visitation during a foraging trip or in time spent foraging on male and female umbels in experimental arrays where the gender ratio was equal. Pollinator assemblages consisting of a mixture of different pollinator types coupled with temporal variation in the assemblages of populations among years maintains generalisation at the population/local level. In addition, spatial variation in assemblages among populations maintains generalisation at the species level. Fire alters pollination in T. incisa by shifting the flowering season and reducing the abundance of flying insects. Therefore, fire plays an important role in maintaining spatial and temporal variation in this fire-prone system. Although insect pollinators are important in determining the mating opportunities of 90% of flowering plant species worldwide, few studies have looked at the effects of variation in pollinator assemblages on plant reproductive success and mating. In T. incisa, high insect visitation rates do not guarantee high plant reproductive success, indicating that the quality of visit is more important than the rate of visitation. This is shown by comparing the Agnes Banks and Myall Lakes populations in 2003: Agnes Banks received the highest visitation rate from an assemblage dominated by ants but produced the lowest reproductive output, and Myall Lakes received the lowest visitation rate by an assemblage dominated by a native bee and produced the highest seedling emergence. Interestingly, populations with different assemblage composition can produce similar percentage seed set per umbel. However, similar percentage seed set did not result in similar percentage seedling emergence. Differences among years in reproductive output (total seed production) were due to differences in umbel production (reproductive effort) and proportion of umbels with seeds, and not seed set per umbel. Trachymene incisa is self-compatible and suffers weak to intermediate levels of inbreeding depression through early stages of the life cycle when seeds are self-pollinated and biparentally inbred. Floral phenology, in the form of synchronous protandry, plays an important role in avoiding self-pollination within umbels and reducing the chance of geitonogamous pollination between umbels on the same plant. Although pollinators can increase the rate of inbreeding in T. incisa by foraging on both male and female phase umbels on the same plant or closely related plants, most consecutive insect movements were between plants not located adjacent to each other. This indicates that inbreeding is mostly avoided and that T. incisa is a predominantly outcrossing species, although further genetic analyses are required to confirm this hypothesis. A new conceptual understanding has emerged from the key empirical results in the study of this model generalised pollination system. The large differences among populations and between years indicate that populations are not equally serviced by pollinators and are not equally generalist. Insect visitation rates varied significantly throughout the day, highlighting that sampling of pollinators at one time will result in an inaccurate estimate and usually underestimate the degree of generalisation. The visitor assemblage is not equivalent to the pollinator assemblage, although non-pollinating floral visitors are likely to influence the overall effectiveness of the pollinator assemblage. Given the high degree of variation in both the number of pollinator species and number of pollinator types, I have constructed a model which includes the degree of ecological and functional specialisation of a plant species on pollinators and the variation encountered across different levels of plant organisation. This model describes the ecological or current state of plant species and their pollinators, as well as presenting the patterns of generalisation across a range of populations, which is critical for understanding the evolution and maintenance of the system. In-depth examination of pollination systems is required in order to understand the range of strategies utilised by plants and their pollinators, and I advocate a complete floral visitor assemblage approach to future studies in pollination ecology. In particular, future studies should focus on the role of introduced pollinators in altering generalised plant-pollinator systems and the contribution of non-pollinating floral visitors to pollinator assemblage effectiveness. Comparative studies involving plants with highly conserved floral displays, such as those in the genus Trachymene and in the Apiaceae, will be useful for investigating the dynamics of generalised pollination systems across a range of widespread and restricted species.