The ant faces many respiratory challenges due to its highly variable environment, which can cause increased desiccation, hypoxia, and hypercapnia. Hot, humid climates cause an increase in heart rate and respiration which increases energy and water loss. Hypoxia and hypercapnia can result from red imported fire ant colonies living in poorly ventilated thermoregulatory mounds and underground nests. Discontinuous gas exchange (DGE) may allow ants to survive the hypercapnic and hypoxic conditions frequently found in their burrows; it is ideal for adapting to these conditions because it allows the ants to increase the period of O2 intake and CO2 expulsion independently through spiracle manipulation. The invasion success of the red imported fire ant may possibly be related to its physiological tolerance to abiotic stress, being more heat tolerant and more adaptable to desiccation stress than "S. richteri". This means that the ant is less vulnerable to heat and desiccation stress. Although "S. richteri" has higher water body content than the red imported fire ant, "S. richteri" was more vulnerable to desiccation stress. The lower sensitivity to desiccation is due to a lower water loss rate. Colonies living in unshaded and warmer sites tend to have a higher heat tolerance than those living in shaded and cooler sites.