THE BIOLOGY OF THE LESSER CLOVER LEAF WEEVIL, HYPERA NIGRIROSTRIS (FABR.) (COLEOPTERA: CURCULIONIDAE), ON RED CLOVER, TRIFOLIUM PRATENSE L., IN SASKATCHEWAN

Abstract

AbstractPopulations of the lesser clover leaf weevil, Hypera nigrirostris (Fabr.), on red clover, Trifolium pratense L., in northeastern Saskatchewan were sampled weekly from May to August 1986 and 1987. Adults overwintered in red clover fields, and began to feed, mate, and oviposit in late April and early May. Eggs were laid subepidermally in stipules, shoots, and leaves from early May to mid-July. Larvae were located on red clover stipules, buds, and fiowerheads and developed through four instars Larvae were collected from early June until mid-August. Spatial distributions of eggs and larvae were aggregated, though the degree of aggregation decreased with succeeding developmental stages. Pupae were collected on shoots and in debris from late June until August. New-season adults first occurred in mid-July; large increases in adult densities corresponded to the appearance of these adults.