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Specific foraging kairomones used by a generalist parasitoid
Johannes L M Steidle1, Anke Steppuhn, Joachim Ruther
1Angewandte Zoologie/Okologie der Tiere, Institut für Biologie, Freie Universität Berlin, Haderslebener Str. 9, 12163 Berlin, Germany. steidle@zedat.fu-berlin.de
Journal of Chemical Ecology
|March 22, 2003
Summary
Generalist parasitoids, like Lariophagus distinguendus, innately use specific chemical cues for host location, challenging previous assumptions. This study identified specific pheromones from Rhyzopertha dominica feces that attract these natural enemies.
Area of Science:
- Entomology
- Chemical Ecology
- Behavioral Ecology
Background:
- Generalist natural enemies are often assumed to lack innate host-specific foraging cues.
- Lariophagus distinguendus is a generalist parasitoid with two known hosts: Rhyzopertha dominica and Sitophilus granarius.
Purpose of the Study:
- To investigate whether naïve Lariophagus distinguendus females use specific innate cues to locate their hosts, Rhyzopertha dominica and Sitophilus granarius.
- To challenge the prevailing hypothesis that generalist natural enemies do not use specific cues for host location.
Main Methods:
- Utilized a four-chamber olfactometer to test female parasitoid attraction to host feces volatiles.
- Performed chemical analysis of volatiles from R. dominica and S. granarius feces.
- Conducted bioassays using synthetic dominicalure and mite-related chemicals.
Main Results:
- Lariophagus distinguendus females were attracted to volatiles from both R. dominica and S. granarius feces.
- Dominicalure 1 and 2, specific aggregation pheromones of R. dominica, attracted naïve parasitoids.
- Chemicals related to mites, not specific to S. granarius, did not attract naïve parasitoids, suggesting innate use of specific cues for R. dominica.
Conclusions:
- The generalist parasitoid L. distinguendus innately uses specific chemical cues for foraging, contrary to initial hypotheses.
- Dominicalure, a specific pheromone of R. dominica, is an innate cue for L. distinguendus.
- The specific innate cues used by L. distinguendus for S. granarius remain to be identified.