IEGEBA (CONICET/UBA), Departamento de Ecología, Genética y Evolución, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria Pab 2, Buenos Aires, Argentina.
J Hered. 2019 Jan 7;110(1):46-57. doi: 10.1093/jhered/esy043.
Host plant shifts in herbivorous insects often involve facing new environments that may speed up the evolution of oviposition behavior, performance-related traits, morphology, and, incidentally, reproductive isolation. In the genus Drosophila, cactophilic species of the repleta group include emblematic species in the study of the evolution of host plant utilization. The South American D. buzzatii and its sibling D. koepferae are a model system for the study of differential host plant use. Although these species exhibit a certain degree of niche overlap, the former breeds primarily on decaying cladodes of Opuntia cacti while D. koepferae main hosts are columnar cacti of the genus Trichocereus. Opuntia sulphurea and Trichocereus terscheckii are among the main hosts in nature. These cacti differ in ecological (spatial and temporal predictability) and chemical characteristics. Particularly relevant is the presence of toxic alkaloids in T. terscheckii. Studies of the effects of these cacti and alkaloids revealed the remarkable impact on oviposition behavior, viability, developmental time, wing morphology, mating success, and developmental stability in both species. Recent whole-genome expression studies showed that expression profiles are massively affected by the rearing cactus, and that the presence of alkaloids is the main factor modulating gene expression in D. buzzatii. Functional enrichment analysis indicated that differentially expressed genes are related to detoxification processes and stress response-though genes involved in development are an important part of the transcriptomic response. The implications of our studies in the evolution of host plant use in the repleta group are discussed.
植食性昆虫的寄主植物转移通常涉及面对新的环境，这可能加速产卵行为、与性能相关的特征、形态的进化，并且间接地促进生殖隔离。在果蝇属中，repleta 组的嗜仙人掌物种包括在研究寄主植物利用进化方面的典型物种。南美果蝇 D. buzzatii 及其姊妹种 D. koepferae 是研究不同寄主植物利用的模式系统。尽管这些物种表现出一定程度的生态位重叠，但前者主要在 Opuntia 仙人掌的腐烂鳞茎上繁殖，而 D. koepferae 的主要寄主是 Trichocereus 属的柱状仙人掌。Opuntia sulphurea 和 Trichocereus terscheckii 是自然界中主要的寄主植物之一。这些仙人掌在生态（时空可预测性）和化学特征上存在差异。特别相关的是 Trichocereus terscheckii 中存在有毒生物碱。对这些仙人掌和生物碱的影响的研究表明，它们对两种物种的产卵行为、生存能力、发育时间、翅膀形态、交配成功率和发育稳定性都有显著影响。最近的全基因组表达研究表明，表达谱受到饲养仙人掌的极大影响，并且生物碱的存在是调节 D. buzzatii 基因表达的主要因素。功能富集分析表明，差异表达的基因与解毒过程和应激反应有关，尽管参与发育的基因是转录组反应的重要组成部分。我们对 repleta 组中寄主植物利用进化的研究的意义进行了讨论。
