FACTORS AFFECTING DISTRIBUTION AND ABUNDANCE OF HYMENOPTEROUS PARASITES OF IPS SPP. BARK BEETLES IN VIRGINIA (COLEOPTERA: SCOLYTIDAE)

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Abstract
Eighteen new host records were established among 12 species of parasites and 4 species of Ips beetles. Large numbers of Ips spp. and their associates were secured by mass rearing in specially constructed rearing drums. Confirmation of parasitism was accomplished by individual rearing of parasites in gelatin capsules from Ips larvae and pupae taken from logs. Some parasites were typically associated with a particular tree host, but it was not determined if it was due to tree host, Ips host, or the physiographic province. Parasitism was highest in the upper bole, especially in loblolly pine, but no correlation with bark thickness was established. The density of Ips attack and the time during which Ips infestations were maintained at one location also did not appear to affect the rate of parasitism. Parasitism was highest in the overwintering broods of Ips.