Duration of plant damage by the tobacco budworm (Heliothis virescens) affects the attraction of a specialist and a generalist parasitoid to cotton odors.
DURATION OF PLANT DAMAGE BY THE TOBACCO BUDWORM (HELIOTHIS VIRESCENS) AFFECTS THE ATTRACTION OF A SPECIALIST AND A GENERALIST PARASITOID TO COTTON ODORS. TOLULOPE MORAWO AND HENRY FADAMIRO, DEPT. OF ENTOMOLOGY, AUBURN UNIVERSITY, AUBURN, AL 36849.
Herbivore-damaged plants release many types of volatile organic compounds (VOCs), which guide parasitoids (beneficial parasitic wasps) to their herbivore hosts. The quantity and quality of VOC blends may be affected by the duration of plant damage. We used as models, Microplitis croceipes (specialist) and Cotesia marginiventris (generalist), to address the evolutionary and mechanistic question of whether the degree of host specificity affects parasitoids' use of plant VOCs for host location. Both wasp species are larval endoparasitoids of the tobacco budworm (Heliothis virescens), an important pest of cotton. Attraction of the parasitoids to VOCs emitted by undamaged (UD), fresh (6 hr infestation) damage (FD), and old (24 hr infestation) damage (OD) cotton plants infested by H. virescens larvae was investigated using a headspace volatile collection system coupled with four-choice olfactometer bioassay. The specialist showed a preference for host-damaged (FD and OD) plants over UD-plants. In contrast, the generalist could not discriminate among treatment plants. Gas chromatography-mass spectrometry (GC-MS) analyses showed qualitative and quantitative differences in the VOC profiles of UD, FD and OD-plants which may explain the observed preferences of the parasitoids. These results suggest a temporal partitioning in the recruitment of the specialist and generalist parasitoids to herbivore-damaged cotton plants, and may have potential ramifications for interspecific competition between parasitoids.
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|Title Annotation:||Biological Sciences Paper Abstracts|
|Publication:||Journal of the Alabama Academy of Science|
|Article Type:||Author abstract|
|Date:||Apr 1, 2014|
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