Cold resistance was measured as chill coma recovery time; an assay used successfully before to demonstrate intraspecific latitudinal and altitudinal patterns. For this, we placed individual one-day old adults in a microcentrifuge tube in an incubator at 4uC at 11am. We chose this chilling temperature based on the cold challenges imposed on the natural adult populations. After 1.5 h each adult was gently placed on its back in a petri dish with roughened bottom at 21uC. We scored recovery times to the nearest second as the time taken for an animal to stand upright. Following recovery, animals were given another hour to allow for the possible upregulation of Hsp70 and were then frozen at 280uC. No animals died during the cold shock. For recovery times, sample size per combination of latitude and temperature varied between 21 and 26 animals. We tested for effects of rearing NSC 632839 temperature, latitude, and population nested in latitude on the dependent variables in separate general linear models. Population nested in latitude was included as a random factor; it was never significant indicating consistent results within a given latitude. In all analyses we also included sex and its interactions but these results are not related to out predictions and did not interfere with the observed patterns and therefore will not be reported. Models on life history initially also included the cold shock treatment to evaluate whether we successfully randomized larvae across the two adult cold shock treatments. Yet, it was never significant and not retained in the final models. The cold shock treatment was also included as a factor when analyzing Hsp70 levels but not when analyzing recovery times because for Norethindrone the latter variable all animals ad been given a cold shock. For the analyses of recovery times and Hsp70 levels we included mass as a covariate, and for the latter also the optical density of the Hela control. Correct degrees of freedom were estimated using the Satterthwaite option. Because the results on larval development time and mass at emergence are not the focus of this paper they are presented in File S2 and Figure S1. In line with the higher perceived time constraints, growth rates were higher in the southern multivoltine than in the northern univoltine populations. Similar latitudinal growth rate patterns associated with changes in voltinism have been documented in butterflies, mosquitoes, and in a previous study on I. elegans. We also found the typical increase in growth rates at higher temperatures. This increase was less pronounced in the southern populations where growth rates were already high at the low temperature, suggesting growth rates were near their physiological maximum. We provide evidence of a novel cost of rapid growth: rapid growth was associated with a reduced cold resistance both at the latitudinal level and at the individual level. Importantly, these patterns cannot simply result from differences in mass, as all analyses were mass-corrected. More generally, our results support the untested hypothesis by Gotthard that faster growing individuals would be worse in dealing with suboptimal temperatures. In ectotherms like damsel- flies that forage and mate in flight, there are obvious fitness implications of a higher cold resistance in the adult stage. Adults with a better cold resistance would better endure cold nights and likely be active earlier in the day, hence can spend more time foraging and engaging in reproductive activities. This cost may be general in animals and plants, yet not directly considered in previous studies.