Life history of Pnigalio soemius (Walker) (Hymenoptera:Eulophidae) and its impact on a leafminer host throughparasitization, destructive host-feeding and host-stinging behavior

摘要

Pnigalio soemius (Walker) (Hymenoptera: Eulophidae) is a polyphagous ectoparasitoid of late instars of leafminer larvae belong-ing to different orders of insects and gall-forming sawflies. Its life history was studied in the laboratory on Cosmopterix pulchrimellaChambers (Lepidoptera: Cosmopterigidae) reared on its natural host Parietaria diffusa M. & K. P. soemius development was short-est at 30 deg C and increased as temperature decreased with an average maximum of 134.8 days at 10 deg C. The lower theoretical thresh-old was 8.8 deg C for both males and females; the optimum developmental temperature and the upper lethal threshold were 28.9 and35.1 deg C, respectively, for males and 28.6 and 34.6 deg C for females. Longevity of fed females and males at 25 deg C +-1, 60 +-10% relativehumidity and 12L:12D averaged 42.5 and 32.3 days, respectively. Females provided with males started oviposition on average 2.2days after emergence and continued ovipositing for 43.0 days after emergence. Each female laid an average of 131.5 eggs and killedan average of 122.2 C. pulchrimella larvae by host-feeding and host-stinging without oviposition. Unmated females produced onlymale progeny. Offspring sex ratio (males/females) of females provided with males throughout their life was 2.76. Superparasitismaveraged 4.1%. The intrinsic rate of increase (r_m) of P. soemius was 0.114, while its kill rate (k_m) was 0.377. The importance ofhost-feeding and host-stinging behavior of P. soemius females on C. pulchrimella populations and its influence on biological controlis discussed.