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Published on: March 12, 2013
Density-dependent effects of multiple predators sharing a common prey in an endophytic habitat
Brian H Aukema1, Murray K Clayton, Kenneth F Raffa
1Department of Entomology, University of Wisconsin, 345 Russell Laboratories, 1630 Linden Drive, Madison, WI 53706, USA. aukema@entomology.wisc.edu
Oecologia
|February 18, 2004
Summary
Predatory insects Thanasimus dubius and Platysoma cylindrica did not unexpectedly impact bark beetle prey Ips pini reproduction. However, intraspecific competition affected predator reproduction, with Thanasimus dubius showing a slight increase in replacement rate when combined with Platysoma cylindrica.
Area of Science:
- Ecology
- Entomology
- Chemical Ecology
Background:
- Multiple predator effects can alter predation outcomes, especially in shared habitats.
- Endophytic insects, common pests, lack studies on multiple predator impacts within their endophytic habitat.
Purpose of the Study:
- To investigate density-dependent predation and reproduction of two predatory beetles (Thanasimus dubius and Platysoma cylindrica) on bark beetle prey (Ips pini) in a shared endophytic habitat.
- To determine if combined predator effects lead to emergent outcomes on prey and predator reproduction.
Main Methods:
- Laboratory assay using multiple regression analysis to assess predator densities on prey establishment, reproduction, and predator reproduction.
- Manipulated densities of Thanasimus dubius and Platysoma cylindrica preying on Ips pini within conifer stems.
Main Results:
- Both predators reduced Ips pini colonization and reproduction, with no unexpected emergent effects from their combination; predators were substitutable.
- Predator reproduction was negatively impacted by intraspecific interference.
- Thanasimus dubius showed a slight increase in net replacement rate when combined with Platysoma cylindrica, potentially due to larval predation on pupal Platysoma cylindrica.
Conclusions:
- The combined effects of Thanasimus dubius and Platysoma cylindrica on Ips pini were additive, not synergistic or antagonistic.
- Intraspecific competition significantly impacted predator reproductive success.
- An emergent effect was observed in Thanasimus dubius reproduction, suggesting complex interactions within the endophytic habitat.
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