Data from: Plastic collective endothermy in a complex animal society (army ant bivouacs: Eciton burchellii parvispinum)

Endothermic animals do not always have a single adaptive internal temperature; some species exhibit plastic homeostasis, adaptively allowing body temperature to drop when thermoregulatory costs are high. Like large-bodied endotherms, some animal societies exhibit collective thermal homeostasis. We tested for plasticity of thermoregulation in the self-assembled temporary nests (bivouacs) of army ants. We measured core bivouac temperatures under a range of environmental conditions and at different colony developmental (larval vs. pupal brood) stages. Contrary to previous assertions, bivouacs were not perfect thermoregulators in all developmental stages. Instead, bivouacs functioned as superorganismal facultative endotherms, using a combination of site choice and context-dependent metabolic heating to adjust core temperatures across an elevational cline in ambient temperature. When ambient temperature was low, the magnitude of metabolic heating was dependent on colony developmental stage: pupal bivouacs were warmer than larval bivouacs. At cooler high elevations, bivouacs functioned like some endothermic animals that intermittently lower their body temperatures to conserve energy. Bivouacs potentially conserved energy by investing less metabolic heating in larval brood because the high costs of impaired worker development may require more stringent thermoregulation of pupae. Our data also suggest that site choice played an important role in bivouac cooling under high ambient temperatures at low elevations. Climate warming may expand upper elevational range limits of Eciton burchellii parvispinum (Forel), while reducing the availability of cool and moist bivouac sites at lower elevations, potentially leading to future low-elevation range contraction.,Bivouac_surveyData collected from a survey of bivouac site choices in Guanacaste and Monteverde. This includes bivouac exposure and whether the bivouac was above-ground or in a cavity under-ground.Brood_ConditionsMean and standard deviation of each bivouac's temperature and relative humidity, as well as temperature and relative humidity recorded at an ambient site on the forest floor 1 m from the bivouac. "NA" entered for relative humidity descriptors in cases where only temperature was measured. All temperatures were recorded using i-button data loggers.Empty_site_conditionsMean and standard deviation of each empty bivouac site's temperature and relative humidity, as well as temperature and relative humidity recorded simultaneously at an ambient site on the forest floor 1 m from the empty bivouac site. "NA" entered for relative humidity descriptors in cases where only temperature was measured. All temperatures were recorded using i-button data loggers.Metabolic_WarmingMean collective metabolic warming for each bivouac, complete with data used to estimate metabolic warming (temperature when ants were present and when absent) and both simultaneously collected ambient temperature, as well as grand mean of ambient temperature across both times when the bivouac was present and when it was absent (regardless of time of day). All temperatures were recorded using i-button data loggers.Timematched_Metabolic_WarmingMean collective metabolic warming for each bivouac, complete with data used to estimate metabolic warming (temperature when ants were present and when absent -using only time-of-day matched absent times) and both simultaneously collected ambient temperature, as well as ambient temperature. All temperatures were recorded using i-button data loggers.,