Department of Fisheries and Wildlife, Michigan State University, East Lansing, Michigan, United States of America.
Department of Integrative Biology, Michigan State University, East Lansing, Michigan, United States of America.
PLoS One. 2022 Nov 21;17(11):e0277336. doi: 10.1371/journal.pone.0277336. eCollection 2022.
Documentation of how interactions among members of different stream communities [e.g., microbial communities and aquatic insect taxa exhibiting different feeding strategies (FS)] collectively influence the growth, survival, and recruitment of stream fishes is limited. Considerable spatial overlap exists between early life stages of stream fishes, including species of conservation concern like lake sturgeon (Acipenser fulvescens), and aquatic insects and microbial taxa that abundantly occupy substrates on which spawning occurs. Habitat overlap suggests that species interactions across trophic levels may be common, but outcomes of these interactions are poorly understood. We conducted an experiment where lake sturgeon eggs were fertilized and incubated in the presence of individuals from one of four aquatic insect FS taxa including predators, facultative and obligate-scrapers, collector-filterers/facultative predators, and a control (no insects). We quantified and compared the effects of different insect taxa on the taxonomic composition and relative abundance of egg surface bacterial and lower eukaryotic communities, egg size, incubation time to hatch, free embryo body size (total length) at hatch, yolk-sac area, (a measure of resource utilization), and percent survival to hatch. Mean egg size varied significantly among insect treatments. Eggs exposed to predators had a lower mean percent survival to hatch. Eggs exposed to predators had significantly shorter incubation periods. At hatch, free embryos exposed to predators had significantly smaller yolk sacs and total length. Multivariate analyses revealed that egg bacterial and lower eukaryotic surface community composition varied significantly among insect treatments and between time periods (1 vs 4 days post-fertilization). Quantitative PCR documented significant differences in bacterial 16S copy number, and thus abundance on egg surfaces varied across insect treatments. Results indicate that lethal and non-lethal effects associated with interactions between lake sturgeon eggs and free embryos and aquatic insects, particularly predators, contributed to lake sturgeon trait variability that may affect population levels of recruitment.
有关不同溪流生物群落成员之间相互作用（例如，微生物群落和表现出不同摄食策略（FS）的水生昆虫类群）如何共同影响溪流鱼类生长、存活和繁殖的记录有限。溪流鱼类的早期生活阶段存在相当大的空间重叠，包括受保护关注的物种，如湖鲟（Acipenser fulvescens），以及大量占据产卵基质的水生昆虫和微生物类群。栖息地重叠表明，跨营养级别的物种相互作用可能很常见，但这些相互作用的结果却知之甚少。我们进行了一项实验，在湖鲟卵受精并孵化的过程中，将其暴露于来自四个水生昆虫 FS 类群的个体中，包括捕食者、兼性和专性刮食者、收集器-过滤器/兼性捕食者和对照（无昆虫）。我们量化并比较了不同昆虫类群对卵表面细菌和低等真核生物群落的分类组成和相对丰度、卵大小、孵化到孵化的时间、孵化时自由胚胎体长（全长）、卵黄囊面积（衡量资源利用的指标）和孵化成活率的影响。不同昆虫处理之间的平均卵大小存在显著差异。暴露于捕食者的卵孵化成活率显著较低。暴露于捕食者的卵孵化时间明显缩短。孵化时，暴露于捕食者的自由胚胎的卵黄囊和全长明显较小。多元分析表明，卵表面细菌和低等真核生物群落组成在昆虫处理之间以及在 1 天和 4 天受精后两个时间段之间存在显著差异。定量 PCR 记录了细菌 16S 拷贝数的显著差异，因此，卵表面的细菌丰度因昆虫处理而有所不同。结果表明，湖鲟卵和自由胚胎与水生昆虫，特别是捕食者之间相互作用的致死和非致死效应导致了湖鲟特征的变异性，这可能影响到种群的繁殖水平。
