Thermoregulation in the primitively eusocial paper wasp, Polistes dominulus

Abstract

Regulation of wing muscle temperature is important for sustaining flight in many insects, and has been well studied in honeybees. It has been much less well studied in wasps and has never been demonstrated in Polistes paper wasps. We measured thorax, head, and abdomen temperatures of inactive Polistes dominulus workers as they warmed after transfer from 8 to *25°C ambient temperature, after removal from hibernacula, and after periods of flight in a variable temperature room. Thorax temperature (T th ) of non-flying live wasps increased more rapidly than that of dead wasps, and T th of some live wasps reached more than 2°C above ambient temperature (T a ), indicating endothermy. Wasps removed from hibernacula had body region temperatures significantly above ambient. The T th of flying wasps was 2.5°C above ambient at T a = 21°C, and at or even below ambient at T a = 40°C. At 40°C head and abdomen temperatures were both more than 2°C below T a , indicating evaporative cooling. We conclude that P. dominulus individuals demonstrate clear, albeit limited, thermoregulatory capacity.

A role for thermoregulation in the Polistes dominulus invasion: a comparison of the thermoregulatory abilities of the invasive wasp P. dominulus and the native wasp P. fuscatus

“…A non-linear regression was used on the cumulative difference between live and dead animals over time to compare the two species. Most of the warming data on P. dominulus found in this paper have been reported by Weiner et al (2010).…”

“…Live and dead wasps were placed in a plastic bag and kept for 10 min at 8°C. The validation of this procedure was presented by Weiner et al (2010). After cooling, wasps were moved to a temperature-controlled room kept at 26 ± 0.6°C, while still restrained.…”

“…Each dead wasp was measured continuously for 10 min and the temperature was recorded every 30 s (Weiner et al, 2010). Each live wasp was used for only one data point.…”

“…For each test, the wasp was released in a temperature-controlled room and allowed to fly for 30-60 s (as in Weiner et al, 2010). After a wasp had flown for 30-60 s, it was captured in a net and immediately restrained in the net against a piece of soft foam.…”

“…Body region temperatures were regressed upon the corresponding T a values, and the slopes were compared between species and to a slope of 1 (representing region temperature = T a ) using an ANCOVA. The P. dominulus portion of this data set has been reported by Weiner et al (2010).…”