Note on Parasitism of Two Coccinellids, Coccinella trifasciata perplexa Muls. and Coleomegilla maculata lengi Timb. (Coleoptera: Coccinellidae) in Ontario

Abstract

In the Belleville, Ontario, district parasitism of 646 adults of Coccinella trifasciata perplexa Muls. by Perilitus coccinellae (Schrank) (Hymenoptera: Braconidae) was approximately seven per cent and of 363 adults of Coleomegilla maculata lengi Timb. 16 per cent in 1959. Mature parasite larvae emerged from both species of host adults after 20.9 ± 6.2 days of host feeding in the laboratory. The duration of the pupal stage was 10.7 ± 0.4 days and of the adult stage 8.9 ± 5.2 days (22°C. and 65 per cent R.H.). The host beetle usually remained inactive after the emergence of the parasite. Its feet were often entangled in the silk of the parasite's cocoon, and it died within 10 days. P. coccinellae emerged from adults of C. maculata obtained from fourth-instar larvae collected in the field and reared to the adult stage in the laboratory, and also from pupae collected in the field. This is the first authenticated record of this parasite attacking a host stage other than the adult in the field (Clausen 1910), and the second record for this species in Canada (Hudon 1959). Parasitized females of C. maculata laid fertile eggs up to 10 days before the emergence of P. coccinellae.