Data from: Day/night upper thermal limits differ within Ectatomma ruidum ant colonies

In the tropics, daily temperature fluctuations can pose physiological
challenges for ectothermic organisms, and upper thermal limits may affect
foraging activity over the course of the day. Variation in upper thermal
limits can occur among and within species, and for social insects such as
ants, within colonies. Within colonies, upper thermal limits may differ
among individuals or change for an individual throughout the day. Daytime
foragers of the Neotropical ant Ectatomma ruidum have higher critical
thermal maxima (CTmax) than nocturnal foragers, but whether these
differences occur among or within colonies was not previously known. We
investigated the potential mechanisms accounting for day/night variation
in CTmax of E. ruidum foragers by testing whether CTmax varied among or
within colonies or due to individuals within colonies acclimating to
changes in temperature over a short time scale (3 h). We found within- but
not among-colony differences in CTmax on a diel cycle, and we found no
evidence for among- or within-colony partitioning of foraging times by
individual workers. Individuals did not acclimate to experimental
manipulations of temperature, although additional experiments with more
ecologically relevant temperature manipulations are needed to rule out
this mechanism. In summary, we have shown that day/night differences in
upper thermal limits can occur within ant colonies, but further
investigation is needed to elucidate the mechanisms driving this
variation.