Fig. 4

Males did not show more structure within days than females. Mean and SD (thick line with shaded surround) of temperature A, B and activity E, F of one male (red) and female (blue) across 24 h, overlaid on 14 days for the same individual (black lines underneath color). Any measurement more than 1 SD from the mean is defined as error. Error summed across 24 h allows comparison of structured variance by sex within a day. Males show significantly higher within individual, within-day error than females (C, G). Structure of the variance appeared similar across sexes; there was no difference between the sexes once each individual’s error was divided by that individual’s mean SD (D, H). This finding demonstrates that males did not have sufficient structure within a day to make them overall less variable if within-a-day structure is accounted for in this way. However, the amount of error was proportional to the SD in both sexes, suggesting that while males were more variable overall, they did not have less structure within a day than did females, by this approach. *Indicates significant difference. See “Results” section for further details