The Effects of Host-Feeding on Synovigenic Egg Development in An Endoparasitic Wasp,Itoplectis naranyae

Abstract

Many adult parasitoids feed on host insects, a behavior known as host-feeding. Feeding on hosts is essential to maximizing female fecundity, but its contribution to reproduction varies from species to species. The relationship between fecundity and host-feeding was examined in the solitary endoparasitoid wasp Itoplectis naranyae Ashmead, (Hymenoptera: Ichneumonidae) to assess the significance of host-feeding in female reproduction. Adult female wasps did not respond to hosts when they were 0–1 days old, but subsequently increased their oviposition and host-feeding activities with increasing female age. While newly emerging females had no mature eggs in their ovary, the number of mature eggs increased rapidly thereafter, a process termed synovigeny. Female wasps were capable of maturing eggs without host-feeding, and this suggested that they produced a certain portion of eggs from nutritional reserves that had been stored during the larval stage. Behavioral observations revealed that I. naranyae was a destructive host-feeder as the host was damaged during feeding. Female fecundity was greater in females that had previously fed on hosts than those did not, indicating that host-feeding was involved in egg production. There was a time-delayed relation between host-feeding events and additional egg production; at least 3 days were required to mature eggs from nutrients gained via feeding on hosts. The significance of host-feeding in I. naranyae reproduction is discussed in the context of its life history traits.

Fecundidad y alimentación de Tamarixia triozae (Hymenoptera: Eulophidae) sobre el psílido de la papa Bactericera cockerelli

“…Suggesting that females of this species during their larval state acquired part of the nutrients used in the production of the first egg. This has been shown in other species (Ueno and Ueno 2007), and might be related to the ability to search for oviposition host immediately but also to stimulate at the same time, the process begins feeding on the host.…”

Host Approaching Behavior in a Parasitoid Wasp (Hymenoptera: Ichneumonidae) as Influenced by Physiological State and Host Type

“…Itoplectis naranyae is a polyphagous solitary endoparasitoid [12,13]. It searches for its host during the daytime by flying or hopping from leaf to leaf or stem to stem.…”

“…The colony was maintained on pupae of a laboratory host, Galleria mellonella (Lepidoptera: Pyralidae). The host was reared on an artificial diet [3,13]. Host cocoons containing fresh pupae were presented to female I. naranyae in plastic containers.…”

Unexpected Use of Pupal Stage of a Lepidopteran Host by the Ectoparasitoid Wasp Agrothereutes lanceolatus (Hymenoptera: Ichneumonidae)

“…After a single oviposition had been confirmed, hosts were removed from the containers to avoid them being superparasitized. Oviposition was confirmed by observing the base of the wasp ovipositor where it was possible to see an egg passing through [24,25]. In all, 38 females were used and thus 76 hosts were parasitized in this experiment.…”