Chrysocharis laricinellae (Ratz.) mated readily in the laboratory when several individuals of both sexes were held together in a vial. The courtship dance performed by the male is described. Parasite females develop mature eggs 3 days after emergence and are apparently capable of resorbing the eggs if hosts are not available, and to produce new ones after host-feeding. Storage of eggs in the ovary for 5 months at 55°F and sterility (phasic castration) of certain individuals is reported. Longevity of egg-laying females at 75°F was about 1 month less than that of parasites that had been denied contact with hosts. Odor apparently plays little or no role in the location of the larch casebearer larvae by C. laricinellae, but chemical surface stimuli seem to exist on the surface of a mine or case of Coleophora laricella (Hbn.). The parasite is also stimulated by vibrations of the host in its case. The oviposition and host-feeding pattern of C. laricinellae is described. Host-feeding on fourth-instar larvae of the larch casebearer contributed little to host mortality.

Laboratory observations on the biology of Ceranthia samarensis (Villeneuve), a tachinid parasitoid of the gypsy moth, were carried out in the laboratory at 22 °C day/15 °C night, 85–90% RH, and a 12L:12D photoperiod. Older (5–6 days post-eclosion) males mated readily with newly emerged females. Mating success was 60%. The gestation period of the mated females was 10–12 days. Laboratory-reared (on diet) second- and third-instar gypsy moth larvae feeding on newly grown foliage of Quercus rubra L. were exposed to gravid females of the parasitoid. Ceranthia samarensis ovolarviposited on the body of the host. The first-instar larva penetrated the host cuticle and developed internally, forming a respiratory funnel that caused a dark circular scar on the lateral side of the caterpillar. The average number of progeny (puparia) produced over the lifetime of a C. samarensis female was 55.0 ± 5.0 (SE) and average longevity was 4.1 ± 1.7 (SE) days. Diapause of the puparia was facultative and induced by temperatures below 20 °C combined with a 12L:12D photoperiod. In nondiapause individuals, total generation time was 22–40 days. To obtain diapause insects, puparia were stored for2monthsat 15 °C, 100% RH, and 12L:12D photoperiod for development of pharate adults. Cold storage at 2–4 °C and 100% RH for at least 5 months was required to obtain up to 75% eclosion after 5–9 days the following year.

No abstract

From 1976 to 1978, 1300 mated females of Olesicampe geniculatae Quednau and Lim were released near Quebec City during a severe infestation of the mountain ash sawfly, Pristiphora geniculata (Hartig). Both cage and open releases were made. The interactions among the mountain ash sawfly, the imported primary parasite O. geniculatae, and the indigenous hyperparasite Mesochorus globulator (Thunb.), and the effect of O. geniculatae on the host population during and after the establishment phase, are reported. In 1984, O. geniculatae was recovered from all over southern Quebec. Parasitism ranged from 6 to 94%. Concurrently, infestation levels by the mountain ash sawfly declined significantly, and since 1985, the insect has almost disappeared in Quebec. With an annual spread of about 50 km per year after successful establishment, O. geniculatae now covers an area 1000 km in diameter. No major infestation by the mountain ash sawfly has been recorded in Quebec during the past 7 years. The introduction of O. geniculatae is rated as a complete success in classical biological control.

Can. Ent. 102: 602412 (1970) Agathis pumila (Ratzeburg) and Chrysocbaris laricinellae (Ratzeburg) compete for their common host, the larch casebearer (Coleophora laricella (Hiibner)). An analysis of the mechanism of this competition, based on a 2-year study at Joliette, Que., is presented. A . pmnila, in sacrificing part of its own population, prevents a "one stage condition" and helps C. laricinellae build up to a point where the latter becomes host-regulative by massive attack. Competitive displacement of A . pumila by C. laricinellae is less frequent than expected because of the basically different ways in which the two parasite species spread, search for, select, and attack hosts.A. pumila may suffer about 50% loss from multiple parasitism, but apparently this does not affect its survival potential, its reproductive rate, and its ability to provide significant partial control of the larch casebearer.nellne, second and third generation adults. 17, hibernating casebearers being attacked by C. IuricinelEae. Volume 102 THE CANADIAN ENrOMOLOGIST AbstractCan. Ent. 102: 612-617 (1970) The proportion of females of the European red mite, Panonychus ulmi (Koch), reared from periodic samples of larvae and nymphs from a peach orchard averaged about 75% with little seasonal variation. A male can copulate at least 11 times in 2 hr, and inseminate at least 26 females during its life span, but many later copulations inseminate the females incompletely or not at all. Some females copulate at least three times but one copulation with a young male enables a female to lay the usual proportion of fertilized (female) eggs, which exceeds that of unfertilized (male) eggs. N o evidence of males with only one nymphal instar, as reported in Europe, was found in mites reared at ISo, 22", or 30°C. Males disperse much more rapidly than females.