Temporal plasticity of thermal tolerance in ants

Authors: ROEDER, DIANE - Augustana University; PARASKEVOPOULOS, ANNA - University Of Colorado; Roeder, Karl

Submitted to: Ecology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/15/2025
Publication Date: 12/8/2025
Citation: Roeder, D.V., Paraskevopoulos, A.W., Roeder, K.A. 2025. Temporal plasticity of thermal tolerance in ants. Ecology. 106(12). Article e70250. https://doi.org/10.1002/ecy.70250.
DOI: https://doi.org/10.1002/ecy.70250

Interpretive Summary: How do individuals tolerate both the hot and the cold climate of our planet? One possibility is that organisms have traits like thermal tolerance that allow them to function in highly variable environments. In this study, we tested whether variation in temperature tolerance occurs in ants. Critical thermal limits often represent physiological points at which organisms lose mobility or muscle control. We first measured the upper and lower critical thermal limits (CTmax and CTmin) of ants monthly for two years. Both CTmax and CTmin were correlated with temperature in a positive, linear manner. We then tested whether CTmax and CTmin could track temperature within a shorter time period by exposing subcolonies of ants to cool (10°C), moderate (20°C), and hot (30°C) temperatures for 10 days. CTmax increased only slightly at the hottest temperature treatment (+1.2°C), however CTmin increased considerably under both moderate (+2.6°C) and hot treatments (+3.8°C). Combined, our results suggest that thermal tolerance of ants may be more variable than originally thought, which could aid these insects under future climate change scenarios.

Technical Abstract: How do individuals tolerate both the hot and the cold climate of our planet? One possibility is that organisms have plastic traits like thermal tolerance that allow them to function in highly variable environments. In this study, we tested whether phenotypic plasticity of temperature tolerance (i.e. acclimatization in the field and acclimation in the lab) occurs in the red harvester ant, Pogonomyrmex barbatus, at two temporal scales. We first measured the upper and lower critical thermal limits (CTmax and CTmin) of ants monthly for two years while concurrently measuring environmental conditions. Both CTmax and CTmin co-varied with temperature in a predictable way; values increased in a positive, linear manner. We then experimentally tested whether CTmax and CTmin could shift within a shorter time period by exposing subcolonies of ants to cool (10°C), moderate (20°C), and hot (30°C) temperatures for 10 days. CTmax increased only slightly at the hottest temperature treatment (+1.2°C), however CTmin increased considerably under both moderate (+2.6°C) and hot treatments (+3.8°C). Combined, our results suggest that thermal tolerance of ants may be more plastic than originally hypothesized, potentially aiding an already thermophilic clade in future climate scenarios.