Trade-offs associated with food availability and predator avoidance behavior of a stream mayfly

Abstract

We studied the effects of food availability and predator cues on mayflies at the Rocky Mountain Biological Laboratory (RMBL) in Gothic, CO. Organisms in a wide variety of ecological systems must deal with trade-offs between functions necessary to sustain their populations. Specifically, we were interested in how food availability in the presence of predators induces changes in predator avoidance behavior, growth rate, and grazer-algal impact. We manipulated the environment of mayflies (Baetis bicaudatus) using treatments with or without chemical cues from brook trout (Salvelinus fontinalis) and different levels of periphyton resources in order to test for trade-offs between food availability and predator avoidance behavior. We found that trade-offs do in fact exist between food availability and predator avoidance behavior. Mayflies only exhibited daytime drift, which is a food search behavior that increases the risk of predation, when there were not only no predator cues present but also when food was limited. However, no trade-offs were observed for mayfly growth rates and grazer- algal impact responses to our manipulation of food availability and predator cues. Mayfly growth rates and grazer-algal impact were significantly affected only by food availability, and not by the presence of predator cues; and predator cues did not affect the influence of food levels on mayfly growth or impacts on algae. Results of this and previous experiments suggest that the nonconsumptive effects (NCE) of trout do not cost Baetis reduced growth rate but rather costs Baetis reduced fecundity due to accelerated development. In the presence of trout, Baetis do not grow more slowly, but incur a size-fecundity trade-off by maturing at smaller sizes. We conclude that trade-offs play important roles in the behavior and fitness of organisms such as Baetis and are key to understanding food web interactions.

Local Knowledge Graph (16 entities)

Related Works

Items connected by shared entities, co-authorship, citations, or semantic similarity.

References (49)

10 in Knowledge Hub, 39 external