EMERGENCE, HOST ATTACK, AND OVERWINTERING BEHAVIOR OF THE EASTERN LARCH BEETLE, <i>DENDROCTONUS SIMPLEX</i> LECONTE (COLEOPTERA: SCOLYTIDAE), IN NEWFOUNDLAND

Abstract

Abstract Overwintered adults of Dendroctonus simplex LeConte emerged in May and June. One generation and two broods were produced in both 1983 and 1984. Females initiated attacks and males arrived within 2 days. One to four pairs of beetles used each entrance hole but each pair constructed a separate egg gallery. Emergence, host attack, and re-emergence occurred between 1030 and 1700 hours NDT and at mean air temperatures above 4°C. Peaks of attack, which reflect flight peaks, occurred at temperatures above 10°C. About 90% of all parents re-emerged from first brood trees and 61% from second brood trees. Only adults overwintered. Freezing temperatures caused complete mortality of immature stages. Thirty-five percent of new brood adults emerged in the fall and re-entered galleries at the base of trees for hibernation. Adult tolerance to cold increased from early fall to mid-winter.