Learning, Host Fidelity, and the Stability of Host-Parasitoid Communities

Area of Science:

• Ecology
• Evolutionary Biology
• Behavioral Ecology

Background:

• Host-parasitoid models predict extinction of less fecund hosts by generalist parasitoids.
• Species coexistence necessitates mechanisms for rare, less fecund hosts to increase population size.

Purpose of the Study:

• Investigate how recently discovered parasitoid learning behavior can facilitate host-parasitoid species coexistence.
• Determine the conditions under which host fidelity supports a stable multihost equilibrium.

Main Methods:

• Developed two ecological models of host-parasitoid interactions with varying parasitoid searching assumptions.
• Incorporated parasitoid learning of natal host chemical cues into the models.
• Derived mathematical conditions for host fidelity strength required for multihost equilibrium.

Main Results:

• Parasitoid learning, or host fidelity, can enable coexistence between hosts with differing fecundity.
• The strength of host fidelity is critical for establishing a feasible multihost equilibrium.
• The multihost equilibrium is stable when individual host-parasitoid equilibria are stable.

Conclusions:

• Parasitoid learning is a significant factor promoting biodiversity in host-parasitoid systems.
• Host fidelity mechanisms are key to preventing the extinction of less competitive host species.
• This research provides a theoretical basis for understanding the stability of multi-host parasitoid communities.