Fig. 3.
The response of critical thermal maximum to laboratory natural selection in four species of springtails. Mean CTmax (±SE) for the temperate indigenous Lepidocyrtus sp. 10 (A), tropical indigenous species Ascocyrtus sp. 2 (B), temperate alien Orthonychiurus sp. (C), and tropical alien Desoria trispinata (D) for each of two lines (filled circles/triangles and solid/dashed lines) evolved under an elevated temperature (red: tropical = 27 °C, temperate = 25 °C) and control lines (blue: tropical = 20 °C, temperate = 15 °C). Open symbols to the right indicate the outcomes of a reciprocal transplant experiment at generations four or six, determining the contribution of developmental plasticity to CTmax. Here, springtails from selection and control groups were reared under either their standard acclimation temperature (A) or transplanted to the thermal environment of the opposing group (T) and reared for one generation. Intergenerational change in CTmax is typically within the scope of developmental plasticity. Effect sizes are typically less than 1 °C (see SI Appendix, Tables S2 and S4 for statistics).