The effect of temperature on evoked activity in giant interneurons was compared in Grylloblatta sp. (an alpine insect with a temperature preference close to 0°C) and Acheta domesticus. The response to sound and air‐puff stimulation of the abdominal cerci was monitored with extracellular electrodes placed under the ventral nerve cord. Responses to air puffs were elicited in Grylloblatta while the animal was supercooled to ‐6°C. The supercooling point was reached and freezing occurred in the range ‐5.5 to 8.5°C. The upper extinction temperature could not be determined due to massive spontaneous giant fibre activity in the 12–15°C range masking responses to air puffs. Lethal heat coma occurred at 15–20°C, although most animals did not recover from the spontaneous CNS activity which preceded it. The extinction ranges for Acheta giant neurons were 3.5‐4.0°C and 42–44°C. Spike number peaked at 33–36 C and amplitude levels diminished as heat or cold coma was approached; ‐7.5 C was the mean supercooling point. Both species recovered from cold coma if supercooling was avoided; in Acheta , heat coma was also reversible. Giant fibre latencies in Acheta displayed a Q 10 of 1.2 above 11–14°C, below which a break occurred in the curve and delays increased sharply. Latencies for the grylloblattid exhibited a Q 10 of 2 but no break in the curve was observed until 0° C was approached. Spike number and amplitude increased with temperature until spontaneous CNS activity obliterated responses to air puffs. The potential role of unsaturated fatty acids in low temperature adaptation in Grylloblatta is discussed.
No takes yet. Share an insight, caveat, or question.
Morrissey et al. (1979) studied this question.