ABSTRACT

Infochemical landscapes, also referred to as landscapes of fear, can strongly influence the distribution of organisms. Planktivore infochemicals alter zooplankton distribution; zooplankton avoid macrophytes in the absence of planktivorous fish and associate with macrophytes when planktivorous fish are present. It is unclear, however, how zooplankton respond to fish with different diets in the presence and absence of habitat. In a laboratory experiment, we evaluated avoidance of Daphnia pulex to 4 fish treatments including a fishless control, a piscivore (muskellunge [Esox musquinongy]) with a diet of planktivores, and a planktivore (bluegill [Lepomis macrochirus]) with either a diet of conspecific zooplankton or a diet of heterospecifics: terrestrial invertebrates (crickets [Acheta domesticus]). These treatments used presence and absence of macrophytes to evaluate whether macrophytes alter responses to these fish treatments. Relative to control treatments, D. pulex avoided bluegill fed D. pulex and did not avoid muskellunge or bluegill fed A. domsesticus. Macrophytes were avoided in all fish treatments. Consumption of D. pulex, which was concurrently evaluated for the 2 bluegill diet treatments, was higher in bluegill fed A. domesticus treatments than in treatments of bluegill fed D. pulex, suggesting differences in behavior based on the presence of different infochemicals. A conceptual model based on results from the present study and the broader literature suggests that infochemical landscapes may cause high association for Daphnia, planktivores, and piscivores with macrophytes, ultimately influencing food web structure through higher encounter rates among taxa.

抽象的

信息化学景观，也称为恐惧景观，可以强烈影响生物体的分布。浮游生物信息化学物质改变浮游动物的分布；浮游动物在没有浮游鱼类的情况下避免大型植物，并在存在浮游鱼类的情况下与大型植物结合。然而，目前尚不清楚浮游动物在有无生境的情况下如何应对不同饮食的鱼类。在实验室实验中，我们评估了避免水蚤对4种鱼的处理方法，包括无鱼对照，食以浮游动物的食食者（muskellunge [ Esox musquinongy ]）和浮游动物（blue（Lepomis macrochirus））]），可以选择同种浮游动物饮食或异种饮食：陆生无脊椎动物（cri [ Acheta domesticus ]）。这些处理方法使用大型植物的存在与否来评估大型植物是否改变了对这些鱼类处理的反应。相对于对照治疗，D。pulex避免饲喂D. pulex的blue，也不避免muskellunge或bluedomill饲养的A. domsesticus。在所有鱼类处理中均避免使用大型植物。同时评估了两种蓝g饮食治疗的D. pulex的消费量，在以蓝g喂养的家养A.处理中比在以蓝g喂养的D. pulex的治疗中更高，根据不同的信息化学品的存在提示行为差异。一个基于本研究结果和更广泛文献的结果的概念模型表明，信息化学景观可能导致水蚤，浮游动物和食肉动物与大型植物高度相关，最终通过更高的分类单元接触率影响食物网的结构。