Abstract：
Native and invasive species often occupy similar ecological niches and environments where they face comparable risks from chemical exposure. Sometimes, invasive species are phylogenetically related to native species, e.g. they may come from the same family and have potentially similar sensitivities to environmental stressors due to phylogenetic conservatism and ecological similarity. However, empirical studies that aim to understand the nuanced impacts of chemicals on the full range of closely related species are rare, yet they would help to comprehend patterns of current biodiversity loss and species turnover. Behavioral sublethal endpoints are of increasing ecotoxicological interest. Therefore, we investigated behavioral responses (i.e., change in movement behavior) of the four dominant amphipod species in the Rhine-Main area (central Germany) when exposed to the neonicotinoid thiacloprid. Moreover, beyond species-specific behavioral responses, ecological interactions (e.g. parasitation with Acanthocephala) play a crucial role in shaping behavior, and we have considered these infections in our analysis. Our findings revealed distinct baseline behaviors and species-specific responses to thiacloprid exposure. Notably, Gammarus fossarum exhibited biphasic behavioral changes with hyperactivity at low concentrations that decreased at higher concentrations. Whereas Gammarus pulex, Gammarus roeselii and the invasive species Dikerogammarus villosus, showed no or weaker behavioral responses. This may partly explain why G. fossarum disappears in chemically polluted regions while the other species persist there to a certain degree. But it also shows that potential pre-exposure in the habitat may influence behavioral responses of the other amphipod species, because habituation occurs, and potential hyperactivity would be harmful to individuals in the habitat. The observed responses were further influenced by acanthocephalan parasites, which altered baseline behavior in G. roeselii and enhanced the behavioral response to thiacloprid exposure. Our results underscore the intricate and diverse nature of responses among closely related amphipod species, highlighting their unique vulnerabilities in anthropogenically impacted freshwater ecosystems.
摘要：
本地和入侵物种通常占据相似的生态位和环境，在那里它们面临着化学暴露的可比风险。有时候,入侵物种与本地物种在系统发育上相关，例如，由于系统发育保守和生态相似性，它们可能来自同一个家庭，并且对环境压力源具有潜在的相似敏感性。然而,旨在了解化学品对所有密切相关物种的细微差别影响的实证研究很少见，然而，它们将有助于理解当前生物多样性丧失和物种周转的模式。行为亚致死终点具有日益增加的生态毒理学兴趣。因此,我们调查了行为反应(即，运动行为的变化）暴露于新烟碱类噻虫啉时，莱茵-美因地区（德国中部）的四种优势两栖动物物种。此外，超越特定物种的行为反应，生态相互作用（例如与棘头寄生）在塑造行为中起着至关重要的作用，我们在分析中考虑了这些感染。我们的发现揭示了对噻虫啉暴露的不同基线行为和物种特异性反应。值得注意的是,Gammarusfosarum在低浓度下表现出双相的行为变化，多动症在高浓度下下降。而Gammaruspulex,Gammarusroeselii和入侵物种Dikerogammarusvillosus，没有或表现出较弱的行为反应。这可能部分解释了为什么在化学污染区域中G.fosarum消失，而其他物种在一定程度上持续存在。但这也表明，栖息地的潜在预暴露可能会影响其他两栖动物物种的行为反应，因为习惯的发生，潜在的多动症会对栖息地的个体有害。观察到的反应进一步受到棘头虫寄生虫的影响，这改变了G.roeselii的基线行为，并增强了对噻虫啉暴露的行为反应。我们的结果强调了密切相关的两栖动物物种之间反应的复杂性和多样性，强调它们在受人为影响的淡水生态系统中的独特脆弱性。
