Non-lethal predator effects on the feeding rate and prey selection of the exotic zebra mussel Dreissena polymorpha

Abstract

Predators may induce changes in prey feeding that indirectly influence both the impact of prey on resource abundances and their interactions with other species in their community. We evaluated whether clearance and excretion (faeces plus pseudofaeces) of phytoplankton by zebra mussels were affected by the presence of predatory cues from roach, Rutilus rutilus, and signal crayfish, Pasifastacus leniusculus. We found that non-lethal effects of predators can alter zebra mussel clearance rate and thus the impact of zebra mussels on phytoplankton. Risk cues released by both predators had similar negative effects on clearance rate of zebra mussels and cascading positive indirect effects on phytoplankton resources. Predation risk had a stronger effect on zebra mussels' clearance rate of cyanobacteria and diatoms than cryptophytes and chrysophytes. The presence of predators did not significantly affect the rate at which zebra mussels expelled and excreted phytoplankton, although there was a tendency for more chlorophyll to be expelled and excreted in the presence of predators. Our results contribute to the growing evidence that predators indirectly affect resource dynamics and food web structure through their non-lethal effects on consumers. Our results suggest that exotic species such as zebra mussels can show behavioural responses to both native (e.g. roach) and exotic (e.g. crayfish) predators.

Published in

Oikos
2007, volume: 116, number: 8, pages: 1289-1298

SLU Authors

• Naddafi, Rahmat

  • Uppsala University

UKÄ Subject classification

Behavioral Sciences Biology
Ecology

Publication identifier

• DOI: https://doi.org/10.1111/j.2007.0030-1299.15695.x

Permanent link to this page (URI)

https://res.slu.se/id/publ/140551