OXYGEN CONSUMPTION OF WHOLE INSECTS AND INSECT HOMOGENATES

¹ Department of Biology, Fordham University, New York 58, New York

1. The oxygen consumption of 10 per cent homogenates of Japanese beetle and mealworm eggs was measured for each day of the embryonic period at 30° C. and compared with that of intact eggs.

2. Homogenization of newly laid Japanese beetle eggs resulted in a reduction of 50 per cent in oxygen consumption. From the third to sixth day, there was no decrease but towards the end of the embryonic period, a reduction of more than 50 per cent was again obtained. Homogenization of mealworm eggs resulted in an average reduction of 48 per cent in oxygen consumption which remained constant throughout the embryonic period.

3. The rates of oxygen consumption of whole mealworm larvae and of their homogenates were determined. Homogenization resulted in a decrease in respiratory rate, the extent depending on homogenate concentration. With 20 per cent homogenates, there was a reduction of 29 per cent; and with 1 per cent homogenates, it was 64 per cent.

4. The effects of homogenization on the respiratory rate of mealworms were determined for each day of metamorphosis at 30° C. Homogenization abolished the U-shaped respiratory curve characteristic of intact pupae. Therefore, the degree of reduction depended on the stage of metamorphosis. With 1 per cent homogenates, it was 61 per cent in prepupae, 80 per cent in newly molted, 50 per cent in two-day, 72 per cent in five-day pupae, and 80 per cent in newly emerged adults. Furthermore, the extent of reduction also varied with homogenate concentration being greater in 1 per cent than in 5 per cent homogenates.