Take a moment to imagine you have wings, no doubt it would be an odd sensation. Now imagine your ears are on your wings- that’s even more odd isn’t it? However, to the Satyrini butterflies this is the reality of their bodily structure.
It has been known to entomologists- those who study insects- for at least a century, that insects have evolved a diverse range of organs crucial for detecting sound and the Satyrini butterflies are no different. They have an ear-like structure located at the base of their forewing. Whilst this itself may seem particularly unusual to us it is the conspicuously swollen vein situated next to the ear-like structure that has been perplexing scientists.
Entomologists have been puzzled by the purpose of this vein, but a recent study conducted by researchers at the University of Toronto in collaboration with those at Carleton University has shown this unusual structure may aid in the butterfly’s ability to hear.
Using 30 specimens of butterfly the researchers began examining the ear membrane and wing vein structures and testing their responses to various frequencies of sound to better understand the purpose of the wing vein.
What they found has taken us one step closer to understanding the complexity of insect’s sensory organs. The inflated vein at the base of the wing is directly connected to the butterfly’s ears and therefore contributes to its ability to hear low frequency sounds. These are sounds of less than 5kHz, if you want to hear exactly what 5kHz sounds like follow the link at the end of this article, but it is within the range of human hearing as we hear from 2-5kHz.
The evidence collected suggests that this enhances the butterfly’s ability to detect sounds of the predators they would most likely encounter during the day, such as birds in flight and predator vocalisations that overlap into the hearing range of these butterflies.
As many small insects face the physical challenges associated with hearing at low frequencies, and due to the benefits to survival it so clearly presents, it is likely that these vein inflations occur in other smaller species of butterfly, something which researchers needs now explore.
What doe 5kHz sound like?