Lepidopteran anti-juvenile hormones: Effects on development of Apanteles congregatus in Manduca sexta

Parasitism by the braconid wasp Apanteles congregatus decreases the effectiveness of the anti-juvenile hormone agents ETB (ethyl 4-2-{ittert-butyl carbonyloxy}bytoxy]benzoate) and fluoromevalonolactone (FMev) in inducing precocious metamorphosis of Manduca sexta larvae. Topical application of 1–200 μg ETB to parasitized third-instar larvae had no effect on either host or parasite development, whereas doses of 50μg or more ETB applied to unparasitized third-instar larvae caused formation of larval-pupal intermediates after the fourth instar. Parasitism also decreased the effectiveness of 100–200 μg FMev in causing metamorphosis at the moult following its application. In contrast to ETB, FMev disrupted development of the parasitoids. No wasps emerged when preterminal stage hosts were treated with FMev and the hosts formed larval-pupal intermediates. After treatment of terminal stage hosts with FMev, the number of emerging parasitoids was reduced by one-third. Precocene II (100 μg per larvae) had no effect on development of either M. sexta or A. congregatus.