The eyes spell doom for brush brown butterflies, as bearing more eyespots on their forewings led to more intense predatory attacks.
Butterflies that are picky about their flower diets are more prone to extinction, researchers have found.
Common Bluebottle butterflies have at least 15 different classes of photoreceptors, or light-detecting cells, in their eyes; no other insect has more than nine.
Lycaenid butterflies secretes nutritious and mind altering nectar to keep attendant ants close by for protection.
An inversion of the supergene containing the doublesex gene determines whether or not female butterflies can mimic their unpalatable relatives.
Japanese researchers have found mutations in butterflies in the Fukushima region, signaling early changes to the local ecosystem after the March 2011 disaster.