Preimaginal development and reproductive responses to temperature in two populations of the Colorado potato beetle (Coleoptera: Chrysomelidae)

The pattern of geographical differences in two populations of the Colorado potato beetle, Leptinotarsa decemlineata (Say), suggests that preimaginal developmental responses and imaginal reproductive responses to temperature are under different selective pressures. Immatures from the warm, coastal (Long Island) area developed slightly slower, had slightly higher thermal thresholds for development, and suffered more mortality at low temperature than immatures from cooler, Upstate New York. However, more females from the Long Island population oviposited fertile eggs at lower temperatures than females from the upstate population. The data suggest that early planting dates and/or bivoltinism in the warm coastal area cause significant selection pressure for fast reproductive development under low temperatures.