EFFECT OF COLD-ACCLIMATION ON COLD RESIST ANCE OF AZUKI-BEAN BEETLE CALLOSOBRUCHUS-CHINENSIS L

Effect of cold acclimation on body weights, survival rates, carbohydra te contents and supercooling points of the azuki bean beetle at differ ent stages were tested under the laboratory conditions. The cold accli mated weevil survived longer period at 0-degrees-C than the non-acclim ated one reared at 25-degrees-C. Especially, the mature larvae contain ing high amount of carbohydrate markedly prolonged the survival period at 0-degrees-C, but in pupae and adults such effects of the cold accl imation were slightly observed. This weevil was a freezing susceptible insect and the supercooling points of larva and pupa were around -22 approximately -26-degrees-C, showing that it can tolerate cold winter temperature. This experiment shows that the mature larva may be favour able to overwinter.