Department for Integrative Evolutionary Biology, Max Planck Institute for Developmental Biology, Max-Planck Ring 9, Tübingen, 720976, Germany.
Department of Biological Sciences, University of Utah, 257 South 1400 East, Salt Lake City, UT, 84112, USA.
Environ Microbiol. 2021 Sep;23(9):5102-5113. doi: 10.1111/1462-2920.15438. Epub 2021 Mar 16.
Cross-kingdom interactions involve dynamic processes that shape terrestrial ecosystems and represent striking examples of co-evolution. The multifaceted relationships of entomopathogenic nematodes with their insect hosts and symbiotic bacteria are well-studied cases of co-evolution and pathogenicity. In contrast, microbial interactions in soil after the natural death of insects and other invertebrates are minimally understood. In particular, the turnover and succession of nematodes and bacteria during insect decay have not been well documented - although it represents a rich ecological niche with multiple species interactions. Here, we utilize developmentally plastic nematode Pristionchus pacificus and its associated scarab beetles as models. On La Réunion Island, we collected rhinoceros beetle Oryctes borbonicus, induced death, and placed carcasses in cages both on the island and in a mock-natural environment in the laboratory controlling for high spatial and temporal resolution. Investigating nematode population density and dispersal dynamics, we were able to connect two imperative plasticities, dauer and mouth form. We observed a biphasic 'boom and bust' dispersal dynamic of dauer larvae that corresponds to bacterial load on carcasses but not bacterial type. Strikingly, all post-dauer adults have the predatory mouth form, demonstrating novel intricate interactions on decaying insect hosts. Thus, ecologically relevant survival strategies incorporate critical plastic traits.
跨物种相互作用涉及塑造陆地生态系统的动态过程，是协同进化的显著例子。昆虫病原线虫与其昆虫宿主和共生细菌的多方面关系是协同进化和致病性的很好的研究案例。相比之下，昆虫和其他无脊椎动物自然死亡后土壤中的微生物相互作用则知之甚少。特别是，在昆虫腐烂过程中，线虫和细菌的更替和演替尚未得到很好的记录——尽管这代表了一个具有多种物种相互作用的丰富生态位。在这里，我们利用发育可塑性线虫 Pristionchus pacificus 及其相关的金龟子作为模型。在留尼汪岛，我们收集了犀牛甲虫 Oryctes borbonicus，诱导其死亡，并将尸体放在岛上的笼子和实验室中的模拟自然环境的笼子中，以进行高时空分辨率的控制。通过研究线虫种群密度和扩散动态，我们能够将两种必需的可塑性， dauer 和口型联系起来。我们观察到 dauer 幼虫的双相“繁荣和萧条”扩散动态，这与尸体上的细菌负荷有关，但与细菌类型无关。引人注目的是，所有 dauer 后的成虫都具有捕食性的口型，这表明在腐烂的昆虫宿主上存在新的复杂相互作用。因此，具有生态相关性的生存策略包含关键的可塑性特征。
