Alloxysta victrix

In Alloxysta victrix, 6-methylhept-5-en-2-one 16, which is produced by both males and females, was identified as potentially attractive to the males and slightly repellent to the females in Y-tube olfactometer assays [60]. In this study, the activity was also dependent on prior exposure of the insects to the compound. Naive insects responded more strongly than previously exposed ones. This underscores a second difficulty in the bioassay-guided identification of parasitoid hymenopteran pheromones the responses are very dependent on the context and on prior exposure. Learning has been demonstrated in several species of parasitic hymenoptera [61-65]. 

The existence of volatile spacing cues has been demonstrated in a number of species. Recently, 6-methylhept-5-en-2-one 16 was shown to be slightly repellent in Y-tube olfactometer assays to Alloxysta victrix (see above). The same compound appears to be involved in defense (see below). 

Sullivan, D. J. (1971) Comparative behavior and competition between two aphid hyperparasites Alloxysta victrix and Asaphes californicus. Env. Ent., 1, 234-44. 

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