Vs. Banschbach et al., NEST TEMPERATURES AND THERMAL PREFERENCES OF A FOREST ANT SPECIES - IS SEASONAL POLYDOMY A THERMOREGULATORY MECHANISM, Insectes sociaux, 44(2), 1997, pp. 109-122
We measured nest temperatures and performed laboratory and field exper
iments that determined thermal preferences of the forest ant Myrmica p
unctiventris Roger. We tested the hypothesis that the seasonal cycle o
f colony splitting (polydomy) that this species undergoes allows it to
warm the brood, enhancing reproductive output. This ant species nests
in performed cavities such as sticks, acorns, and hickory nuts. Labor
atory choice experiments indicated that ants preferred to nest at a te
mperature between 16 degrees C and 21 degrees C. Workers and brood had
very similar temperature preferences; queens had slightly higher temp
erature preferences. Field measurements of nest temperatures in Vermon
t recorded an average summer daytime nest temperature of 22.6 +/- 0.38
degrees C s.e., n = 53 nests, with few differences between temperatur
es in different types of nesting materials. Field experiments demonstr
ated that ants colonized artificial nest sites on cooler plots prefere
ntially to those on warmer plots (artificial nest sites on these plots
differed by 1 degrees C in temperature, on average). Our results indi
cate that M. punctiventris preferred to nest at temperatures at the co
oler end of the spectrum of available nest sites in the field. Thus, o
ur results lend no support to the hypothesis that seasonal polydomy is
a thermoregulatory mechanism that these ants employ to place their br
ood in the warmest available nest sites.