← Back to PublicationsStudent Paper

The effect of long-term metal exposure and mermithid parasitism on behavior and predation of nymphal <i>Baetis bicaudatus</i> by <i>Megarcys signata</i>

Authors: Hamilton, J. H.ORCID
Mentor: Barbara L. Peckarsky
Year: 2013
Publisher: UNKNOWN
Keywords: PREDATOR-PREY INTERACTIONS, PARASITISM, ENVIRONAL STRESS, METAL POLLUTION, STREAM INSECTS

Abstract

Abiotic stressors can affect organisms both directly and indirectly by causing behavioral changes and altering species interactions. Metal pollution caused by mining activities is a major stressor on freshwater ecosystems, particularly affecting macroinvertebrate communities. Historical mining has led to increased acid drainage resulting in high metal concentrations in streams that bioaccumulate from primary consumers to the predators and parasites that feed on those organisms. Our study aims to assess the prevalence of mermithid nematode parasites (Gasteromermis sp.) in mayfly hosts (Baetis bicaudatus), common stream insects, in metal- polluted compared to reference (unpolluted) streams. We also examined the direct effects of exposure to metals and parasites on mayfly behavior and the indirect effects on the predator-prey relationship between stoneflies and mayflies. To assess the response of B. bicaudatus to biotic and abiotic stressors, we conducted experiments in streamside microcosms and compared the foraging and drift dispersal behavior of parasitized and unparasitized individuals originating from metal-polluted and non-polluted streams. In addition, we experimentally assessed predation rates of Baetis by stoneflies (Megarcys signata) in response to exposure to metal pollution and mayfly parasitism. We found that prevalence of parasites in mayflies was uniformly high in metal-rich streams, but highly variable in reference streams. Parasitized mayflies from all streams more actively foraged for algal resources, and parasitized mayflies from a metal-rich stream were more susceptible to predation by stoneflies than parasitized mayflies from unpolluted streams and all unparasitized individuals. These results agree with previous studies on aquatic insect responses to environmental stressors. Furthermore, observed induced changes in mayfly behavior show that abiotic stressors and parasitic infections may mediate predator-prey interactions in aquatic insect communities. 2

Local Knowledge Graph (15 entities)

Loading graph...