Insect Thermoregulation

THERMOREGULATION IN INSECTS--In The Snoring Bird, Heinrich writes of several of his discoveries. Among them is his discovery of thermoregulation in insects. Heinrich writes, "Superficially, sphinx moths resemble hummingbirds. They are close analogues, similar in size, swift and agile in flight, and colorful. The lined sphinx (Hyles lineata) has a soft "fur" of green and tan scales and its pink underwings are framed in black while the abdomen has patches of white. I wanted to catch one of these moths, and when one stopped nearby to hover and sip nectar from a Belloperone flower (where the hummingbirds had fed minutes earlier) I had my chance. With a swoop of my net I had one fluttering inside against the gauze. I grabbed the moth between my thumb and forefinger, struck the point of a tiny thermometer probe called a thermocouple into the flight muscles of its thorax, and quickly read the instrument's dial. The needle jumped to indicate a whoppingly hot body temperature of 42.5 degrees Celcius (108 degrees Fahrenheit)--and it stayed there for several seconds until the moth, now stationary, gradually started to cool. The temperature on the dial--ten degrees Fahrenheit higher than human body temperature--startled me. Maintenance of a high body temperature was considered an advanced trait of the "higher" vertebrate animals, mammals, and birds. Others, like fish, amphibians and reptiles, were thought to be "cold-blooded" because they are unable to generate sufficient internal heat to sustain a high body temperature." Heinrich would go on to understand the mechanism by which some insects can elevate their temperature (read on in his book), but his initial discovery was simply that insects could elevate their body temperatures above ambient conditions at all.