Host Age Effects on Ovipositional and Developmental Biology of Baryscapus chrysopae (Hymenoptera: Eulophidae), a Parasitoid of Chrysopid Larvae

The parasitoid, Baryscapus (=Tetrastichus) chrysopae (Crawford), is a widely-distributed gregarious parasitoid of chrysopid larvae. The ovipositional and developmental biology of this parasitoid in relation to the stage of its host, Chrysoperla rufilabris (Burmeister), was examined. Female B. chrysopae attacked all larval stages of the host tested (instars 1 to 3), and paralyzed all hosts soon after mounting and stinging. During the host's paralysis, females oviposited in and fed on hosts. The time females spent on hosts was directly related to host stage. All hosts recovered from paralysis. Parasitoid developmental time was inversely related to host stage and ranged from 27.5 d in 1-d-old hosts to 20.5 d in 10-d-old hosts. Most development of parasitoid larvae appears to occur after the host has spun its pupal cocoon. The number of parasitoids produced per host was unrelated to host stage, ranging from 10.5 (in 1-d-old hosts) to 14.2 (in 7-d-old hosts) parasitoids per host. The sex ratio was skewed toward females (81.6% pooled across host stages) and was unrelated to host stage. The developmental biology of B. chrysopae appears to be well synchronized with that of its host.