The thermal tolerance of a species may be exceeded by the predicted temperature increases and thus contribute to population extinctions. However, the impact of temperature increases is thought to vary between climate regions, with latitude and by local climate, life history traits and inter- and intraspecies interactions. Here, we aim to establish the vulnerability of ectothermic insects to a warming climate by estimating the thermal buffer, the difference between critical thermal maximum (CTmax) and the maximum temperature of the warmest month in Ischnura heterosticta damselflies across a 2700 km cline. We measured CTmax along a latitudinal gradient of seventeen degrees from twenty-one populations along the eastern coast of Australia. Our results showed that damselflies inhabiting in tropical regions had higher CTmax than temperate damselflies and CTmax increased with increasing temperatures but not with decreasing latitudes as predicted. We further found that individuals with high parasite numbers had higher CTmax, while body size, body condition and sex had no impact on CTmax. Our projections showed that damselfly thermal buffer will be narrower in the tropics compared to temperate regions under a predicted 2.6°C degree annual mean temperature increase. Therefore, damselflies in the tropics are likely to be more vulnerable to climate change driven extinction even though they have a relatively higher CTmax.

Insects exhibit diverse colours that play a crucial role in communication that directs inter- and intra-species interactions such as predator-prey interactions and sexual selection. Anthropogenic climate change may impact insects colour expression and consequently their physiology and behaviour. Insects can respond to changing climatic through phenotypic plasticity or genetic modification, however it is unclear how any of the resulting changes in body and wing colour may impact interactions with conspecifics and heterospecific (e.g., predator, prey, and mate). The aim of this review is to synthesis the current knowledge of the consequences of climate driven colour change on insects. Firstly, we discussed the environmental factors that affect insect colours, and then we outlined the adaptive mechanisms in terms of phenotypic plasticity and microevolutionary response. Secondly, we conducted a systematic review and performed a qualitative analysis to understand how experimental rearing temperature influences insect colouration. Finally, we gave an overview of the beneficial or maladaptive impact of colour change on sexual selection. We concluded by identifying research gaps and highlight potential future research areas.