SUPPLEMENTAL FEEDING INCREASES THE UTILIZATION OF A FACTITIOUS HOST FOR REARING BRACON THURBERIPHAGAE MUESEBECK (HYMENOPTERA, BRACONIDAE) APARASITOID OF ANTHONOMUS-GRANDIS BOHEMAN (COLEOPTERA, CURCULIONIDAE)

Bracon thurberiphagae is a parasitoid attacking Anthonomus grandis thu rberiae, the thurberia weevil. Although B. thurberiphagae can be reare d on the boil weevil, the host is expensive to maintain in the laborat ory and varies greatly in quality. Heliothis virescens was tested as a n alternate host for rearing B. thurberiphagae because of their more c onsistent quality and availability, but after three generations the B. thurberiphagae population was severely reduced. After the addition of several amino acids to an adult wasp diet, a 100% improvement in the fecundity of B. thurberiphagae reared on H. virescens was observed and a 1:1 sex ratio was restored. This resulted in the ability to maintai n a strong colony on an otherwise unsuitable factitious host. The rear ing of B. thurberiphagae on H. virescens did not alter their response to boil weevil cues. These results are important in that they demonstr ate that the selection of factitious hosts does not necessarily depend on whether the host is suitable, but that the suitability may be mani pulated to some degree. (C) 1995 Academic Press, Inc.