5 | CONCLUSION
Our study highlights the importance of the mechanistic links of colour
lightness and body size with the temperature regime which shapes the
biogeographical patterns of dragon- and damselflies (Odonata). Colour-
and size-based thermoregulation were by far the dominant mechanisms
shaping the composition of assemblages of odonates, although other
functions of body size and colour lightness seemed to influence the
geographical patterns of both traits to some extent. The consistency of
our findings together with the results of a number of macroecological
analyses underlines the general importance of thermal melanism and
Bergmann’s rule for ectothermic organisms. However, besides highlighting
the crucial role of traits involved in thermoregulation in shaping the
distribution of odonate species, our results indicate that difference in
species’ dispersal propensities embedded in the spatio-temporal
stability of their habitats contributes to explaining the scatter around
the considered trait-environment relationships as well as to differences
in the relative contributions of climatic predictors. Thus, thermal
adaptations seem to be of similar evolutionary importance for lentic and
lotic species but a greater dispersal ability of the former in
combination with the climatic history of Europe seem to have allowed
them better cope with historical climatic changes.