Estudo das barreiras reprodutivas no gênero Panstrongylus (Hemiptera, Triatominae)
Data
2019-02-22
Autores
Reis, Yago Visinho dos
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
Os triatomíneos são insetos hematófagos suscetíveis à infecção pelo protozoário Trypanosoma cruzi, agente etiológico da doença de Chagas. Todas as espécies são potenciais vetoras do parasito, embora algumas sejam consideradas de importância primária, que são associadas ao domicílio humano, e outras de menor importância, devido à associação apenas com habitats silvestres. Considerando que as alterações climáticas e ações antrópicas no meio ambiente podem influenciar na distribuição de espécies que antes estavam isoladas, conhecer o potencial de hibridização entre elas é extremamente importante, pois a produção de híbridos pode levar a eventos de introgressão e especiação. Levando em consideração que para o clado geniculatus (agrupamento das espécies de Panstrongylus spp. + Nesotriatoma spp. + Triatoma tibiamaculata) não existem estudos que avaliem a hibridização entre essas espécies, o objetivo deste trabalho foi avaliar a presença de barreiras reprodutivas por meio de cruzamentos interespecíficos experimentais entre quatro espécies do clado geniculatus. Para cada par de espécies foram montados três cruzamentos em cada direção. Os experimentos foram mantidos durante quatro meses e os casais foram alimentados semanalmente, assim como a contagem de ovos. Em todos os cruzamentos não houve eclosão de ovos, demonstrando a presença de barreiras pré-zigóticas entre todas as espécies analisadas. Esses resultados não eram esperados, uma vez que, mesmo entre espécies filogeneticamente distantes, de outros grupos da tribo Triatomini, existe a possibilidade de hibridação, ressaltando a importância desse grupo para estudos evolutivos. Além disso, consideramos também, que mesmo que essas espécies se encontrem no futuro, devido às mudanças ambientais, as fortes barreiras reprodutivas impedirão a produção de híbridos entre elas.
Triatomines are hematophagous insects susceptible to infection by the protozoan Trypanosoma cruzi, an etiologic agent of Chagas' disease. All species are potential vectors of the parasite, although some are considered of primary importance, which are associated to human domicile, and others of minor importance, due to the association with wild habitats only. Considering that climate change and anthropogenic actions in the environment may influence the distribution of species that was previously isolated, knowing the hybridization potential between them is extremely important, since the production of hybrids can lead to introgression and speciation events. Considering that for clado geniculatus (grouping of the species of Panstrongylus spp. + Nesotriatoma spp. + Triatoma tibiamaculata) there are no studies that evaluate the hybridization between these species, the objective of this work was to evaluate the presence of reproductive barriers by means of Interspecific crosses between four species of geniculatus clade. For each pair of species, three crosses were assembled in each direction. The experiments were maintained for four months and the couples were fed weekly, as well as the egg count. In all the crosses there was no hatching of eggs, demonstrating the presence of pre-zygotic barriers among all species analyzed. These results were not expected, since even among phylogenetically distant species, from other groups of the Triatomini tribe, there is the possibility of hybridization, emphasizing the importance of this group for evolutionary studies. In addition, we also believe that even if these species meet in the future due to environmental changes, strong reproductive barriers will prevent the production of hybrids between them.
Triatomines are hematophagous insects susceptible to infection by the protozoan Trypanosoma cruzi, an etiologic agent of Chagas' disease. All species are potential vectors of the parasite, although some are considered of primary importance, which are associated to human domicile, and others of minor importance, due to the association with wild habitats only. Considering that climate change and anthropogenic actions in the environment may influence the distribution of species that was previously isolated, knowing the hybridization potential between them is extremely important, since the production of hybrids can lead to introgression and speciation events. Considering that for clado geniculatus (grouping of the species of Panstrongylus spp. + Nesotriatoma spp. + Triatoma tibiamaculata) there are no studies that evaluate the hybridization between these species, the objective of this work was to evaluate the presence of reproductive barriers by means of Interspecific crosses between four species of geniculatus clade. For each pair of species, three crosses were assembled in each direction. The experiments were maintained for four months and the couples were fed weekly, as well as the egg count. In all the crosses there was no hatching of eggs, demonstrating the presence of pre-zygotic barriers among all species analyzed. These results were not expected, since even among phylogenetically distant species, from other groups of the Triatomini tribe, there is the possibility of hybridization, emphasizing the importance of this group for evolutionary studies. In addition, we also believe that even if these species meet in the future due to environmental changes, strong reproductive barriers will prevent the production of hybrids between them.
Descrição
Palavras-chave
Barreira pré-zigótica, Cruzamento interespecífico, Reduviidae, Doença de Chagas, Pré zygotic barries, Interspecific crossing, Chagas disease, Insects vectors, Insetos vetores