CBGP, INRAE, CIRAD, IRD, Montpellier SupAgro, Univ Montpellier, Montpellier, France.
Department of Entomology, Cornell Institute of Host-Microbe Interactions and Disease, Cornell University, Ithaca, NY, USA.
Microbiome. 2023 Sep 7;11(1):201. doi: 10.1186/s40168-023-01617-8.
The influence of microbiota in ecological interactions, and in particular competition, is poorly known. We studied competition between two insect species, the invasive pest Drosophila suzukii and the model Drosophila melanogaster, whose larval ecological niches overlap in ripe, but not rotten, fruit.
We discovered D. suzukii females prevent costly interspecific larval competition by avoiding oviposition on substrates previously visited by D. melanogaster. More precisely, D. melanogaster association with gut bacteria of the genus Lactobacillus triggered D. suzukii avoidance. However, D. suzukii avoidance behavior is condition-dependent, and D. suzukii females that themselves carry D. melanogaster bacteria stop avoiding sites visited by D. melanogaster. The adaptive significance of avoiding cues from the competitor's microbiota was revealed by experimentally reproducing in-fruit larval competition: reduced survival of D. suzukii larvae only occurred if the competitor had its normal microbiota.
This study establishes microbiotas as potent mediators of interspecific competition and reveals a central role for context-dependent behaviors under bacterial influence. Video Abstract.
微生物群在生态相互作用中的影响，特别是在竞争中的影响，知之甚少。我们研究了两种昆虫物种之间的竞争，入侵害虫果蝇 suzukii 和模式果蝇 melanogaster，它们的幼虫生态位在成熟但未腐烂的果实中重叠。
我们发现 D. suzukii 雌性通过避免在 D. melanogaster 先前访问过的基质上产卵来防止代价高昂的种间幼虫竞争。更准确地说，D. melanogaster 与乳杆菌属的肠道细菌的共生关系触发了 D. suzukii 的回避。然而，D. suzukii 的回避行为是有条件的，如果 D. suzukii 自身携带 D. melanogaster 细菌，它们就会停止回避 D. melanogaster 访问过的地点。通过在果实内重现幼虫竞争实验，证明了避免来自竞争者微生物群的线索的适应性意义：只有当竞争者有其正常的微生物群时，D. suzukii 幼虫的存活率才会降低。
本研究确立了微生物群作为种间竞争的有力介导物，并揭示了在细菌影响下依赖于背景的行为的核心作用。视频摘要。
