Biology of Chrysocharis pentheus, an Endoparasitoid Wasp of the Citrus Leafminer Phyllocnistis citrella Stainton

The biology of Chrysocharis pentheus (Walker) (Hymenoptera: Eulophidae), the most abundant endoparasitoid of Phyllocnistis citrella Stainton (Lepidoptera: Gracillariidae) in Ehime prefecture, Japan, was studied under laboratory and field conditions. The mean immature developmental time and adult longevity at different temperatures (۲۲ to ۳۱°C) under ۵۰-۷۰% RH decreased as the temperature increased, and females survived longer than males. The developmental threshold of male and female was ۸.۹°C and ۱۱.۹°C, respectively. The effective accumulative temperature (thermal constant) for males and females from egg to adult was ۱۸۱.۸ and ۲۳۸.۱ degree-days, respectively. C. pentheus appeared to be a synovigenic species. The offspring sex ratio from females provided with males was ۷۳.۸% males and ۲۶.۲% females. Presumably, mated females began oviposition ۱-۲ days after emergence and continued for up to ۴۰ days. Females laid a mean of ۱۱۸.۲±۱۰.۱۰ eggs each, and their longevity reached ۳۲.۳±۰.۳۰ days at ۲۷±۱°C, ۵۰-۷۰% RH. The intrinsic rate of natural increase (rm) was ۰.۱۴۴. Host feeding or stinging without oviposition killed ۶۵.۷±۸.۶۵ P. citrella larvae per female. Oviposition in the field was highest (۶۲.۷%) on the third instar larva of P. citrella, with the rest on the prepupal stage (۳۷.۳%), showing a significant preference for third instars. The sex ratio (M:F) of C. pentheus reared from the third instar larvae of host and pupae was ۳.۳:۱.۰ and ۱.۰:۳.۰ respectively.

کلیدواژه ها:

Chrysocharis pentheus ، fecundity ، Longevity ، Phyllocnistis citrella ، sex ratio