Integrando traços fenotípicos na filogeografia de insetos neotropicais
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Data
2024-06-25
Autores
Machado, João Roberto Fentanes [UNIFESP]
Orientadores
Bonatelli, Isabel Aparecida da Silva [UNIFESP]
Tipo
Trabalho de conclusão de curso de graduação
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Resumo
O entendimento da distribuição das espécies ao longo do tempo é fundamental para a compreensão dos processos evolutivos que moldaram a biodiversidade em uma região. Alterações na distribuição das populações são frequentemente associadas a eventos geológicos e climáticos. Em especial, as oscilações climáticas do Pleistoceno parecem ter causado alterações significativas a nível global na distribuição das espécies. Porém, o número de estudos com invertebrados na região Neotropical é escasso. Diversos estudos na região evidenciaram que espécies que habitam biomas úmidos comumente apresentam respostas concordantes a alterações climáticas do passado, enquanto espécies de biomas secos e abertos exibem respostas idiossincráticas a esses mesmos eventos. Os padrões discordantes parecem não ser explicados somente por fatores ambientais. A integração de fatores bióticos e abióticos que moldam as respostas dos organismos representa uma maneira robusta para explorar as diferentes dimensões que contribuem para o estabelecimento de padrões demográficos. No presente trabalho, foi aplicada uma abordagem de filogeografia preditiva para identificar as respostas demográficas de espécies de insetos durante as mudanças climáticas do Pleistoceno e investigar a associação das respostas com diferentes traços biológicos das espécies. Foram analisadas 53 espécies, distribuídas em um total de 8 biomas neotropicais (31 exclusivas de biomas úmidos, 6 exclusivas de biomas secos e 16 generalistas) da classe Insecta (Coleoptera, Diptera, Lepidoptera, Odonata e Trichoptera). A metodologia do trabalho envolveu quatro atividades principais: (i) delimitação de linhagens pelo método bGMYC (Bayesian generalized mixed yule-coalescent model); (ii) teste de modelos demográficos (i.e. expansão, retração ou estabilidade) por computação Bayesiana aproximada; (iii) identificação de variáveis preditoras das diferentes respostas por aprendizagem de máquina com o método Random Forest; (iv) estimativa de alterações na distribuição das espécies por modelagem de nicho ecológico. Como resultado do ABC, 8 espécies mostraram sinal de estabilidade durante as alterações climáticas do Pleistoceno, 3 parecem ter sofrido retrações e 17 expandiram. Como resultado da modelagem de nicho, ao se comparar o período do Último Máximo Glacial com o presente, observou-se uma maior adequabilidade nas condições climáticas atuais, sugerindo uma expansão de 75% das espécies estudadas para o presente. As variáveis biológicas com maior capacidade de predição da resposta demográfica foram o nível taxonômico de família, período de atividade, tipo de habitat das espécies e nível trófico. Com base nos resultados obtidos, fica evidente que as alterações climáticas impactaram a classe Insecta na região Neotropical, resultando predominantemente em respostas demográficas de expansão para o presente. Além disso, os tipos de respostas das espécies às mudanças climáticas do Pleistoceno parecem estar associados a características biológicas das espécies.
Understanding the distribution of species over time is fundamental to comprehending the evolutionary processes that have shaped biodiversity in a region. Changes in population distribution are often associated with geological and climatic events. In particular, the Pleistocene climatic oscillations appear to have caused significant global changes in species distribution. However, the number of studies on invertebrates in the Neotropical region is scarce. Various studies in this region have shown that species inhabiting humid biomes commonly exhibit concordant responses to past climatic changes, while species from dry and open biomes display idiosyncratic responses to these same events. The discordant patterns do not seem to be explained solely by environmental factors. Integrating biotic and abiotic factors that shape organismal responses represents a robust way to explore the different dimensions that contribute to the establishment of demographic patterns. In the present study, a predictive phylogeography approach was applied to identify the demographic responses of insect species during the climatic changes of the Pleistocene and to investigate the association of these responses with different biological traits of the species. Fifty-three species of Insecta (Coleoptera, Diptera, Lepidoptera, Odonata, and Trichoptera) were analyzed. The individuals were distributed across a total of eight Neotropical biomes (31 exclusive to humid biomes, 6 exclusive to dry biomes, and 16 generalists). The study methodology involved four main activities: (i) lineage delimitation using the bGMYC method (Bayesian generalized mixed Yule-coalescent model); (ii) testing demographic models (i.e., expansion, contraction, or stability) through approximate Bayesian computation; (iii) identifying predictor variables of different responses using machine learning with the Random Forest method; (iv) estimating changes in species distribution through ecological niche modeling. As a result of the ABC, 8 species showed signs of stability during the Pleistocene climatic changes, 3 appeared to have experienced contractions, and 17 expanded. As a result of niche modeling, the response pattern comparing the Last Glacial Maximum to the present indicated signs of greater suitability in current climatic conditions, suggesting an expansion of 75% of the studied species to the present. The biological variables with the highest predictive power for demographic response were family, activity period, habitat type, and trophic level. Based on the results obtained, it is evident that climatic changes impacted the Insecta class in the Neotropical region, predominantly resulting in expansion demographic responses. Furthermore, the types of species' responses to Pleistocene climatic changes seem to be associated with the species' biological characteristics.
Understanding the distribution of species over time is fundamental to comprehending the evolutionary processes that have shaped biodiversity in a region. Changes in population distribution are often associated with geological and climatic events. In particular, the Pleistocene climatic oscillations appear to have caused significant global changes in species distribution. However, the number of studies on invertebrates in the Neotropical region is scarce. Various studies in this region have shown that species inhabiting humid biomes commonly exhibit concordant responses to past climatic changes, while species from dry and open biomes display idiosyncratic responses to these same events. The discordant patterns do not seem to be explained solely by environmental factors. Integrating biotic and abiotic factors that shape organismal responses represents a robust way to explore the different dimensions that contribute to the establishment of demographic patterns. In the present study, a predictive phylogeography approach was applied to identify the demographic responses of insect species during the climatic changes of the Pleistocene and to investigate the association of these responses with different biological traits of the species. Fifty-three species of Insecta (Coleoptera, Diptera, Lepidoptera, Odonata, and Trichoptera) were analyzed. The individuals were distributed across a total of eight Neotropical biomes (31 exclusive to humid biomes, 6 exclusive to dry biomes, and 16 generalists). The study methodology involved four main activities: (i) lineage delimitation using the bGMYC method (Bayesian generalized mixed Yule-coalescent model); (ii) testing demographic models (i.e., expansion, contraction, or stability) through approximate Bayesian computation; (iii) identifying predictor variables of different responses using machine learning with the Random Forest method; (iv) estimating changes in species distribution through ecological niche modeling. As a result of the ABC, 8 species showed signs of stability during the Pleistocene climatic changes, 3 appeared to have experienced contractions, and 17 expanded. As a result of niche modeling, the response pattern comparing the Last Glacial Maximum to the present indicated signs of greater suitability in current climatic conditions, suggesting an expansion of 75% of the studied species to the present. The biological variables with the highest predictive power for demographic response were family, activity period, habitat type, and trophic level. Based on the results obtained, it is evident that climatic changes impacted the Insecta class in the Neotropical region, predominantly resulting in expansion demographic responses. Furthermore, the types of species' responses to Pleistocene climatic changes seem to be associated with the species' biological characteristics.