Springer Online Journal Archives 1860-2000
Chemistry and Pharmacology
Abstract When the effect of the kairomone, tricosane, on parasitization byTrichogramma achaeae Nagaraja and Nagarkatti of eggs ofHeliothis zea (Boddie) was studied in petri dish tests, the greatest percentage parasitization ( $$\mathop X\limits^\_$$ = 64%) was obtained if the entire filter paper was treated. Treatment of smaller areas (about the eggs) resulted in decreased parasitism. In the greenhouse, highest parasitization ( $$\mathop X\limits^\_$$ = 71%) byT. pretiosum (Riley) ofH. zea eggs placed on pea seedlings grown in pie pans was obtained if the whole pan was treated; lowest parasitism ( $$\mathop X\limits^\_$$ = 29%) occurred when the pans were untreated. Parasitization was intermediate ( $$\mathop X\limits^\_$$ = 52%) in other pans treated only at selected spots. Dissections ofH. zea eggs collected from kairomonetreated and untreated field plots revealed that eggs ofTrichogramma spp. were more efficiently distributed (less superparasitism) among host eggs in treated plots. These kairomones increase parasitization ofTrichogramma spp. by releasing and continuously reinforcing an intensified searching behavior rather than by attracting and guiding the parasite directly to the host.
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