Timothy M. Casey

Metabolic rate and endothermy in sphinx moths

Summary1.The rate of increase in thoracic temperature was strongly dependent on ambient temperature during pre-flight -warm-up in the sphinx moths,Hyles euphorbia andDeilephila elpenor (Figs. 1, 2).2.The duration of pre-flight warm-up at 19–21 ° C was not correlated with mean body weight (0.3–3.5 g) in 13 species of sphinx moths (Kg. 3).3.The mean rates of oxygen consumption during uninterrupted free flight forH. euphorbia andD. elpenor were 55 and 60 ml O2/g/hr respectively, regardless of air temperature at 15 and 22 ° C (Table 1, Fig. 4).4.Thoracic temperature of sphinx moths of 13 species in free flight in the field usually ranged from 38 to 43 ° C, being independent of mean body weight (Fig. 5) but strongly correlated with weight-relative wing area (Fig. 6).5.These data, which give no indication of regulation of heat production during warm-up or during flight, are in marked contrast with numerous previous publications on endothermy in moths.

Physiological responses to temperature of caterpillars of a desert population of Manduca sexta (lepid: Sphingidae)

Abstract 1. 1. Total transpiration varied from 1.13 mg cm −2 hr −1 at T a = 25°C to 6.07 mg cm −2 hr −1 at 45°C. At any given temperature cuticular transpiration was not significantly different. These rates were higher than any desert insect but not unusual when compared with those of other terrestrial arthropods. 2. 2. Oxygen consumption showed little change between 25 and 35°C but had a Q 10 of about 2 between 15 and 25 and between 35 and 40°C. 3. 3. Growth rates increased with increasing T a to a maximum of 2.3 g/day at 30°C and declined at higher T a . 4. 4. Heart rates are tightly coupled to body temperature and were similar at a given T b during heating and cooling. 5. 5. The present study gives no indication of physiological control of T b or any special adaptations of M. sexta to hot, dry environments.