Monarch butterflies who have dark orange wings fly further than those with light orange wings, a new study has revealed.
Previous work has shown that monarch colouring is intended to warn their predators about their bitter taste and toxicity, and that migratory butterflies are darker coloured than non-migratory ones, suggesting an association between darker colour and increased fitness.
The current work, led by Andrew Davis of the University of Georgia, provides further evidence for this association.
The researchers tested 121 captive monarchs in an apparatus called a tethered flight mill, where they can quantify butterfly flight speed, duration, and distance, and found that those with darker orange wings overall flew longer distances than those with lighter wings.
“Butterfly researchers don’t often look closely at colour variation between individuals of the same species. The results of this project will pave the way for a new line of inquiry into the significance of butterfly wing colour,” Davis said.
The study was recently published in the journal PLoS ONE.