1992 Volume 38 Pages 109-116
As the insects are poikilothermic, body temperature fluctuates with ambient temperature and there is a possibility of freezing during overwintering. Against freezing, insects are devided into two groups; Freeze tolerant species which tolerate extracellular freezing and freeze-intolerant species which indicates freeze-avoidance. With the exception of the freeze-tolerant species with very high degree of supercooling the main difference between the two strategies (freeze-tolerance and freeze-intolerance) is the winter loss or masking of nucleators on freeze-intolerant species, and synthesis or unmasking of nucleating agents in freeze-tolerant species. Ice nucleation active bacteria (INAB), Erwinia herbicola were found in diamond-back moth (Plutella xylostella) pupae. The bacteria may be the origin of ice nucleation activity in the pupae. Because INAB exist on the leaves of many plant species and are distributed all over the world, it is highly possible that phytophagous insects take INAB on feeding and this may cause a death on hibernating.
