Fig 1.
Schematic figure of the experimental design used.
Eggs collected from stock population females were randomly divided and exposed to six temperatures for 24 hours each. Thereafter, one day-old hatchlings were exposed to either 27°C or 37°C, after which survival and head capsule width were measured. Another cohort of resulting hatchlings was reared under control conditions until adult eclosion and then exposed for 24 h to 37°C, after which heat survival and other traits were scored.
Fig 2.
Egg survival rates in relation to temperature (a; 24 h at 27, 29, 31, 33, 35 or 37°C), hatchling survival rates in relation to egg temperature and heat stress (b; exposure of hatchlings for 24 h to 27°C or 37°C), and head capsule (HC) width in relation to egg temperature and heat stress for dead and alive individuals (c) in Bicyclus anynana. Given are means ± 1 SE. Sample sizes range between 132 and 199 groups (a), 23 and 55 groups (b), and 6 and 55 groups (c) with 10 individuals each. Different lower case letters above bars indicate significant differences among egg temperatures (Tukey’s HSD for unequal sample size).
Fig 3.
Survival rates until pupation and adult eclosion (a) and male and female adult body mass (b) in relation to egg temperature (24 h at 27, 29, 31, 33, 35 or 37°C) in Bicyclus anynana. Given are means ± 1 SE. Sample size were 5 cages with 30 individuals each (a) and 29 to 73 individuals each (b). Different lower case letters above bars indicate significant differences among temperatures (Tukey’s HSD for equal sample size).
Table 1.
Results of general linear models (GLMs) for the effects of (a) egg temperature on egg survival rate, (b) egg temperature and larval heat stress on hatchling survival rate, (c) egg temperature, larval heat stress and survival (dead versus alive individuals) on head capsule width of hatchlings, and for the effects of egg temperature on the survival rate during (d) the larval and (e) the pupal stage in Bicyclus anynana.
Significant P-values are given in bold.
Table 2.
Results of a nominal logistic regression for the effects of egg temperature (fixed), cage (nested within temperature; random), sex (fixed), adult body mass, thorax-abdomen ratio and abdomen fat content (covariates) on adult heat survival in Bicyclus anynana.
Significant P-values are given in bold.
Table 3.
Results of general linear mixed models (GLMMs) for the effects of egg temperature (fixed), cage (nested within temperature; random), and sex (fixed) on (a) adult body mass, (b) thorax-abdomen ratio, and (c) abdomen fat content in Bicyclus anynana.
Significant P-values are given in bold.