Developmental Biology of Apanteles yakutatensis (Hymenoptera: Braconidae), a Primary Parasite of Autographa californica (Lepidoptera: Noctuidae)1

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Abstract
The developmental biology of Apanteles yakutatensis (Ashm.), a primary, gregarious, larval endoparasite of Autographa californica (Speyer) was investigated. Adult parasites live an average of 18.0 (females) and 16.5 (males) days when fed a 30% honeywater solution. With water only, adult parasites (both sexes) live an average of 2.5 days. Three larval instars were observed. The first instar is mandibulate, while the others are hymenopteriform. Larvae require 162 degree-days above 10.5°C and pupae 85 degree-days above 9.4°C to complete development. Developmental time from egg to pupa is 10.5 days at 26°C. Host age at parasitization has no significant effect on development times of A. yakutatensis at 26°C. However, the host age at parasitization does affect the time required for the host to reach the prepupal phase, the stage from which larvae of A. yakutatensis exit the host. Hosts parasitized as fourth instar larvae exhibit a supernumary instar and require a longer time to reach the prepupal stage than do those parasitized as younger instars. Hosts parasitized as first instar larvae died. The number of A. yakutatensis larvae per host does not affect the percentage of parasite larvae successfully emerging from an individual host. There is a weak negative relationship between number of parasite larvae per host and mean weight of parasite adults.