REDUCTION OF COLD INJURY IN FLIES USING AN INTERMITTENT PULSE OF HIGH-TEMPERATURE

Exposure to 0 °C reduced injury in flesh flies (Sarcophaga crassipalpis) subsequently cold shocked at -10 °C, but the protection generated reached a maximum after 1 day at 0 °C and was eventually lost within 20 days when the flies were held constantly at 0 °C. Injury, however, was reduced by interrupting the 20-day interval on Day 10 with a pulse of higher temperature (15 °C). Pulse temperatures ≤ 10 °C or ≥20 °C were ineffective. The 15 °C pulse was only effective in generating protection from cold shock injury and did not reduce the indirect chilling injury observed in flies held at 0 °C. These results suggest that the use of intermittent pulses of high temperature could be exploited during cold storage of insects to maintain protection against cold shock injury. Naturally occurring temperature cycles may sustain cold tolerance in a similar manner. © 1992.