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Pogonomyrmex californicus, Linepithema humile, native and invasive species, optimum performance, running speed, climate change, temperature, Bernard Field Station


The ability of a species to tolerate high temperatures may be indicative of its population’s ability to adapt to Earth’s changing climate. We analyzed differences in ant speed, an indicator of ant performance, for the native ant species Pogonomyrmex californicus (California Harvester ants), and the invasive Linepithema humile (Argentine ants) at various temperatures in order to understand the effect of temperature on ant species at the Robert J. Bernard Biological Field Station in Claremont, California. We hypothesized that as temperature increased, performance would increase in both species due to their thermophilic qualities, up to some “thermal optimum” and then decline. Because Argentine ants are invasive species, we predicted that they would have a broader thermal range than Harvester ants. We did not find evidence of a linear correlation between temperature and running speed for either species. Our results suggest that the Argentine ants have a greater thermal optimum thanHarvester ants, though further analysis is needed to determine the thermally optimum temperature.

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