Thermoregulatory behaviour and thermal tolerance of three species of Conidae in the Eastern Pacific and Gulf of California coasts of Baja California, Mexico

ABSTRACTWe investigated three species of Conidae, one on the western shores of Baja California (Californiconus californicus), and two in the Gulf of California (Conasperella perplexus and Conasperella ximenes). In a thermal horizontal gradient trial with day–night cycles, we determined the final thermal preference of three species of snails. Californiconus californicus had a preferred average temperature of 23.3 °C, compared with 22.7 °C for Co. perplexus whereas Co. ximenes had a diel preference of 20.1 °C during the day and 27.2 °C at night. The displacement velocity in Ca. californicus during the day was 12.6 ± 1.9 cm h−1 versus 17.6 ± 2 cm h−1 at night; for Co. perplexus it was 3.8 ± 0.67 cm h−1 in the day and 4.16 ± 0.72 cm h−1 at night; and for Co. ximenes it was 19.3 ± 2.5 cm h−1 during the day and 18.3 ± 2.6 cm h−1 during the night. The critical thermal maximum, the temperature at which at least 50% of the experimental group experiences a loss of attachment, differed between Conasperella species f...