Climate change is causing dragonflies to lose their 'bling'
With their colourful bodies and glistening wings, dragonflies are without a doubt one of the most striking insects in the animal kingdom. But a new study has warned that rising global temperatures could be having a devastating effect on male dragonflies' 'bling'. The 'bling' dark patches on the wings is disappearing in response to rising temperatures in an effort to keep the insects cool. However, the patches are integral for males to attract a mate, and their loss could affect the insects' ability to breed, according to the researchers. Michael Moore at Washington University in St Louis, who led the study, explained: 'Our study shows that the wing pigmentation of dragonfly males evolves so consistently in response to the climate that it's among the most predictable evolutionary responses ever observed for a mating-related trait. 'This work reveals that mating-related traits can be just as important to how organisms adapt to their climates as survival-related traits.' Many species of dragonfly have dark patches on their wings, which they use to attract potential mates and intimidate rivals. 'Beyond its function in reproduction, having a lot of dark pigmentation on the wings can heat dragonflies up by as much as 2 degrees Celsius, quite a big shift,' Mr Moore said. 'While this pigmentation can help dragonflies find mates, extra heating could also cause them to overheat in places that are already hot.' In the study, the team created a database of 319 dragonfly species, examining their wings from photos submitted to iNaturalist and comparing these to climate information on the locations where the insects were spotted. Their analysis revealed that male dragonflies nearly always responded to warmer temperatures by evolving less wing pigmentation. Mr Moore explained: 'Given that our planet is expected to continue warming, our results suggest that dragonfly males may eventually need to adapt to global climate change by evolving less wing coloration.' Strangely, only the male wing pigmentation appears to be affected by warming climates, and females' wings are unaffected. 'Unlike the males, dragonfly females are not showing any major shifts in how their wing coloration is changing with the current climate,' Mr Moore added. 'We don't yet know why males and females are so different, but this does show that we shouldn't assume that the sexes will adapt to climate change in the same way.' Worryingly, the changing male wing colouration could make it trickier for females to find males of the same species to mate with. Mr Moore concluded: 'Rapid changes in mating-related traits might hinder a species' ability to identify the correct mate. 'Even though our research suggests these changes in pigmentation seem likely to happen as the world warms, the consequences are something we still really don't know all that much about yet.'