Project Directorate of Biological Control, P.B. No. 2491, H.A. Farm Post, Hebbal, Bangalore-560024, Karnataka, (India).
Chrysoperla carnea (Stephens), the important predator of aphids and Heliothis armigera (Hübner), showed ovipositional attractant behaviour to the kairomonal substances like L-tryptophan and honey dew. An electroantennogram (EAG) response of C. carnea to some kairomonal substances was studied in the laboratory. The mated and unmated males and females of C. carnea showed EAG response to the 50% honey and L-tryptophan. Among them, the mated females showed higher response than others. Further, EAG response was studied to kairomonal substances like tryptophan-valine combinations and indole acetaldehyde using mated females. Tryptophan continued to elicit better EAG response than others. A comparison of acid hydrolysed and oxidised L-tryptophan also revealed that acid hydrolysed L-tryptophan evoked more EAG response than oxidised L-tryptophan. The response to the breakdown product indole acetaldehyde was comparatively less than L-tryptophan alone.
