Low respiration rates, immobility, lack of feeding, and undeveloped reproductive systems confirmed a summer diapause in the overwintered and current-year adults of the clover leaf weevil, Hypera punctata, and lesser clover leaf weevil, Hypera nigrirostris. The prolonged summer diapause and extended winters in Wisconsin set strict limitations on the available time for damaging populations to develop on red clover, Trifolium pratense thus assuring the status of these weevils as minor pests.
Latsinger, James A. and Apple, James W.
"Summer Diapause of the Clover Leaf Weevil, Hypera Punctata, and Lesser Clover Leaf Weevil, Hypera Nigrirostris, in Wisconsin,"
The Great Lakes Entomologist: Vol. 17
, Article 6.
Available at: http://scholar.valpo.edu/tgle/vol17/iss2/6