Abstract
Supercooling points (SCP) and cold tolerance of the tobacco cutworm, Spodol~rera litura Fabricius. were measured in response to subzero temperatures. SCPs were varied among developmental stages. Eggs showed the lowest SCP (-27$^{\circ}$C). Pupae and adults had the intermediate SCP(- 18$^{\circ}$C). The SCPs (- I0 to - 16$^{\circ}$C) of larvae increased with their ages. Lethal low temperature of each stage was higher than its SCP. Preexposure of eggs and larvae to a sublethal low temperature increased their survival capacities under lethal low temperatures. The sublethal temperature also induced the fifth instar larvae to increase hemolymph osmolality and to produce cold-induced proteins of apparent molecular weights of 20 and 27 kD. These results indicate that this species is classified into a freeze-susceptible insect.
