Parasite escape through trophic specialization in a species flock

Adaptive radiation occurs when species diversify rapidly to occupy an array of ecological niches. Since opportunities for parasite infection and transmission may greatly vary among these niches, adaptive radiation is expected to be associated with a turnover of the parasite community. As major agents of natural and sexual selection, parasites may play a central role in host diversification. The study of parasite turnover may thus be of general relevance and could significantly improve our understanding of adaptive radiation. In the present study, we examined the parasite faunas of eleven species belonging to the tribe Tropheini, one of several adaptive radiations of cichlid fishes in Lake Tanganyika. The most parsimonious ancestral foraging strategy among the Tropheini is relatively unselective substrate browsing of aufwuchs. Several lineages evolved more specialized foraging strategies, such as selective combing of microscopic diatoms or picking of macro-invertebrates. We found that re...适应辐射（Adaptive radiation）是指物种快速分化以占据一系列生态位的演化过程。由于不同生态位间的寄生虫感染与传播机会差异悬殊，适应辐射往往伴随寄生虫群落的更替。作为自然选择与性选择的核心介导因子，寄生虫可能在宿主分化进程中发挥关键作用。因此，针对寄生虫群落更替的研究具有广泛的学术价值，可显著深化我们对适应辐射机制的理解。在本研究中，我们对坦噶尼喀湖（Lake Tanganyika）慈鲷鱼（cichlid fishes）多支适应辐射类群之一的饰首鱼族（Tropheini）所包含的11个物种的寄生虫区系展开了调查。饰首鱼族中最简约的祖先觅食策略为相对无选择性的周丛生物（aufwuchs）基底啃食。多个演化支系演化出更为特化的觅食策略，例如选择性梳食微观硅藻，或是捕食大型无脊椎动物。我们发现……