Microhabitat and Elevational Patterns in Thermal Tolerance and Thermoregulation of Neotropical Army Ants (Formicidae: Dorylinae)

摘要

Temperature is a major abiotic factor governing organismal performance and biotic distribution patterns worldwide. How different spatial resolutions of temperature variation relate to the thermal adaptiveness of organisms living within these environments informs predictions of physiological range limitations and response to climate change. Here I use Neotropical army ants as a model system to test broadly developed macrophysiological predictions on the scale of tropical microclimates and elevation clines. Social insect colonies make particularly interesting models for this purpose, as they enable the testing of predictions on both the level of the individual and the social group (colony). Here I form a new set of predictions for how insect societies are constrained and benefited by their thermal environments. I demonstrate novel patterns in tropical thermal tolerance due to soil microhabitat, elevation, and seasonality and discuss how these patterns interplay with the adaptiveness of castes in ant colonies. I also report novel differences in social thermoregulation across an elevational thermal cline and across brood ages in an above-ground nesting army ant species with a detailed study of thermal tolerance and thermoregulation in a below-ground army nest. The findings of this work suggest benefits in the incorporation of detailed microclimate use and social parameters in models predicting the ecological effects of climate change. These projects also form new testable hypotheses for future work relating to the thermal ecology of social insects.