Ice nucleation activity in a New Zealand alpine cockroach Celatoblatta quinquemaculata (Dictyoptera: Blattidae)

The New Zealand alpine cockroach Celatoblatta quinquemaculata (Dictyoptera: Blattidae) survives temperatures up to 5°c below its supercooling point (scp) of -5.4°C in summer-acclimated samples. This high Scp suggests that C. quinquemaculata utilises potent ice nucleators to avoid extensive supercooling. The distribution of ice nucleating agents within the cockroach was investigated by measuring the SCP and ice nucleator activity of component parts of the body. Both the haemolymph and gut contain high numbers of nucleators active at -4°C. It is proposed that insects of this category, which possess limited freeze tolerance, should be termed moderately freeze tolerant.