Thermal response of lipid composition is stronger for surface dwelling than for soil dwelling springtail species

Species living under large thermal fluctuations possibly need more flexible physiological capabilities than species living in more stable thermal environments. Deep-soil dwelling species habituate more stable thermal environments than surface dwelling species. We compared the flexibility of lipid composition in response to two acclimation temperatures of soil (4), near surface (2), and surface (3) dwelling species of Collembola. Chill coma recovery time (CCRt) and heat knock down time (HKDt) were assessed for soil (2) and surface (2) dwelling species. Surface dwelling Collembolan species showed a lipid composition more flexible in response to acclimation temperature compared to soil dwelling species and thus showed a larger physiological adaptation capacity to temperature. HKDt was more sensitive to acclimation temperature than CCRt: HKDt increased after warm acclimation in all species, whereas only a single species had improved cold tolerance after cold acclimation. In response to extreme heat, surface dwelling species were less sensitive to acclimation temperature. Strong physiological responses to temperature fluctuations may have become redundant in soil dwelling species due to relative thermal stability of their subterranean habitat. Unless soil dwelling species can hide from extreme temperature, low thermal plasticity renders soil dwelling species more vulnerable to climate change. This study shows the importance of investigating the physiological plasticity in relation to thermal phenotypic adaptation and meets the current demand for multidisciplinary studies on ecology and physiology.