Identification of physiological processes setting thermal tolerance limits is essential to describe adaptive response to temperature changes. We use the North American Daphnia pulex complex, which makes a remarkable model for comparative physiology as it is composed of clones differing in heat tolerance, ploidies and with a wide geographic distribution. The fatty acid composition of 18 diploid and triploid D. pulex clones acclimated to 16°C and 24 °C was measured and compared to their tolerance to extreme high and low temperatures (CTmax and CTmin). Eicosapentaenoic acid relative content (EPA) showed a strong negative relationship with CTmax and a clear association with CTmin. Higher unsaturation and peroxidation index were associated with better cold tolerance, while saturated fatty acids (SFA) and monounsaturated fatty acids (MUFA) were associated with lower cold tolerance. Triploid Daphnia accumulated more eicosapentaenoic acid (EPA) and had lower CTmin than diploid clones (better cold tolerance). Triploid clones retained more omega-6 polyunsaturated fatty acids at high temperature. CTmax was positively correlated to CTmin, suggesting the existence of important constraints in temperature tolerance caused by fatty acid composition.
Fatty acid profiles and tolerance to temperature extremes in Daphnia
Sensory perception in a changing world – join us in Liverpool in March 2025
We are excited to invite you to a unique scientific conference, celebrating the 100-year anniversary of The Company of Biologists, and bringing together our different communities. The conference will incorporate the JEB Symposium Sensory Perception in a Changing World and the SEB satellite meeting. Find out more and register to join us in March 2025 in Liverpool, UK. Submit your abstract by 17 January 2025. Early-bird registration ends on 17 January 2025.
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