Fig. 3. Relationship between cholesterol content and habitat temperature in copepods. Cholesterol content (µg cholesterol mg^–1 protein) plotted against both maximum habitat temperatures (filled circles) and temperature tolerance based on LD₅₀ (open circles). Species identifications given adjacent to markers: (1) Euchaeta norvegica, (2) Calanus glacialis, (3a) Calanus finmarchicus cold acclimated, (3b) C. finmarchicus warm acclimated, (4a) Acartia hudsonica cold acclimated, (4b) A. hudsonica warm acclimated, (5a) Acartia tonsa cold acclimated, (5b) A. tonsa warm acclimated, (6a) Temora longicornis cold acclimated, (6b) T. longicornis warm acclimated, (7) Centropages hamatus, (8) Centropages typicus, (9) Eurytemora affinis. To conform to the conditions experienced by the other copepods, E. affinis was acclimated to seawater (32 p.p.t.) for 7 days. Data are presented as mean ± s.e.m. Sample sizes are N=10 for E. norvegica, C. typicus and E. affinis; N=8 for C. finmarchicus, N=6 for C. glacialis and T. longicornis, and N=2 for A. hudsonica, A. tonsa, and C. hamatus. Correlation analysis of temperature tolerance, r²=0.82, significance level P<0.001, maximum habitat temperature r²=0.84, significance level P<0.001.