Synchronized Group Foraging, Thermoregulation, and Growth of Eastern Tent Caterpillars in Relation to Microclimate

Foraging patterns of genetically similar colonies of Eastern tent caterpillars were continuously recorded in the field (in normal and artificially manipulated microenvironments) and in the laboratory. Frequency and duration of foraging bouts were similar despite average daytime body temperatures, which differed by as much as 15 C. Caterpillars which had access to radiant heat regulated their body temperature. Body temperature of caterpillars without radiant heating passively followed ambient conditions. Growth of tent caterpillars was positively correlated with body temperature and paralleled rates of food processing, as indicated by rates of feces production immediately after feeding. Behavioral thermoregulation enhances growth rates in tent caterpillars by increasing rates of food processing during inactive periods, presumably increasing the amount eaten in the next feeding bout.