Document: FRE-3-56-21

Scared stable: Host behavioral response and biological control.

ADLER, F.R.*

University of Utah, Salt Lake City, UT 84112 USA ¹

Abstract:
Numerous mechanisms have been proposed to explain the successful biological control of pests with parasitoids or predators at a low stable equilibrium, but costly defensive behaviors by the pests have only rarely been considered. In fact, it has been suggested that host defenses might make successful control less likely. However, when aphids, for example, drop off a plant in response to attack by a predator or parasitoid, they suffer a large decrease in expected fitness even when the defense is successful. I use simple models of host-parasitoid interactions to show that such a costly behavioral defense is sufficient to stabilize an intrinsically unstable interaction at a low equilibrium value. Even when costly defenses are induced by a cue of potential attack rather than attack itself, the degree of defense leading to stabilization at a low equilibrium can be evolutionarily stable. I apply these models to the control of pea aphids (Acyrthosiphon pisum) by coccinellids (Coccinella septumpunctata).

Keywords: biological control, host-parasitoid interactions, behavioral defense

This abstract is being presented at: 10:30 AM in session:
Oral Session #26: Invertebrate Herbivore - Plant Interactions.