EFFECTS OF TEMPERATURE ON RATES OF OXYGEN-CONSUMPTION DURING MORPHOGENESIS AND DIAPAUSE IN EGG STAGE OF LEPTOPTERNA-DOLOBRATA (HETEROPTERA, MIRIDAE)

O2 consumption at 25.degree. C was measured continuously throughout the egg stage of L. dolobrata (> 9 mo.). The rate of O2-uptake (.mu.l O2/100 eggs .cntdot. 1 h) was low in freshly laid eggs. On maintaining the eggs at a constant temperature of 16.degree. C, respiration rose abruptly from the 1st day after oviposition and continued rising steadily for 3 days, reaching an average value of 1.4 .mu.l. O2 consumption persisted at or near this high level during the developmental phase of prediapause, which lasted .apprx. 15 days. After some days of oscillating high and low values, respiration decreased, and from the 24th day a low level (0.3-0.4 .mu.l) was reached. If the eggs were incubated at 16.degree. C continuously, this low diapause-level was maintained until the end of the experiments (42 wk) and diapause was terminated in a few eggs only. A significant increase in the success of hatching was obtained by exposing eggs to a sufficient period of chilling. Diapausing eggs (24 groups) were chilled at 5.degree. C for certain periods (10, 18, 22, 26, 31, and 34 wk) and later transferred to 16.degree. C and reincubated. The O2-uptake changes at 25.degree. C were traced throughout the chilling and re-incubation periods. O2 consumption was greatly accelerated during cold treatment. The low values of the diapause-level were raised progressively during the first 6 wk of chilling. After this primary rapid increase, respiration remained at a level 5 times as high as the diapause values over a period up to the 25th wk at 5.degree. C. This was almost exactly the duration of mesodiapause (6 mo.). The rates of O2-uptake during the subsequent re-incubation at 16.degree. C depended on the extent of chilling. The ability to break diapause was correlated to the rates of O2-uptake, measured after setting of re-incubation. If respiration never decreased by the onset of re-incubation, diapause was terminated in most of the eggs, and rates of O2-uptake increased as re-incubation progressed towards larval emergence (postdiapause period). A preliminary interpretation of the cold-stimulated O2-uptake in diapausing Leptopterna-eggs was given.