Fig. 3

Ambient temperature in relation to the duration of the breeding season (n = 213 species). a Dots indicate the average ambient temperatures for species with breeding seasons of different lengths (measured in months). GSD species are shown in purple, whereas TSD species are shown in green. The number of species included in each category is indicated by the size of the dots. Shaded areas represent the annual temperature range (average maximum and minimum temperatures) for the species in each category. The yellow line at 25 °C indicates the approximate average ambient temperature for the majority of the groups. Temperature is given in Celsius. b Boxplots representing ambient temperatures associated with TSD or GSD species with either long breeding seasons (5–12 months) or short breeding seasons (1–4 months). Significant differences (Mann-Whitney U test): Benjamin Hochberg-corrected P < 0.05 of temperatures against a reference value of 25 °C (shared average ambient temperature for the majority of groups in panel a); grey filled squares denote non-significant differences, whereas green filled squares denote significant differences (significant P values are indicated). Error bars, maximum and minimum values, excluding outliers. Temperature is given in Celsius