BIOLOGICAL AND CHEMICAL CHARACTERIZATION OF A KAIROMONE EXCRETED BY THE BEAN APHIDS, APHIS-FABAE SCOP. (HOM., APHIDIDAE), AND ITS EFFECT ONTHE PREDATOR METASYRPHUS-COROLLAE FABR. II - BEHAVIORAL-RESPONSE OF THE PREDATOR METASYRPHUS-COROLLAE TO THE APHID KAIROMONE

The present study shows the importance of aphid-kairomone as an additi onal stimulus which arrests and increases the occurrence of the predat or M. corollae with the treated plants. This increase in occurrence co uld assist in the control of the aphid-pest when applied in the target area. The results are summarized as follows. (1) The first concentrat ion of aphid-extract (AEC(1)) stimulated the oviposition of syrphid fe males much more than the second concentration of hexacosane (C26CII) a nd the addition of hexacosane to the aphid-extract did not increase it s activity. (2) The experienced syrphid females deposited more eggs wi th C26CII, AEC(1) and with a mixture of both than did the inexperience d females. (3) The aphid-extract (AEC(1)) and hexacosane (C26CII) affe cted the searching behaviour of syrphid females by significantly incre asing the path length and the number of turns exhibited. (4) The syrph id females were significantly arrested by plants treated with either C 26CII or AEC(1). (5) The results confirm that the predator syrphid fem ales have used hexacosane and aphid-extract as a source of kairomone.