Some Butterflies Hear Through Their Wings

butterflies, hearing
The hearing structure in the wings of some butterflies, such as the common wood nymph (Cercyonia pegala), may help them tune into a wide spectrum of low-frequency sounds. Wikimedia Commons/USED UNDER CREATIVE COMMONS CC BY-ND 2.0

Have you ever tried to tell your problems to a butterfly? It might not be able to understand you — what with the language barrier — but new research suggests that they can at least hear you. Not only that, some butterflies can listen to you with their wings.

The fact that many groups of butterflies hear with little holes at the base of their wings — cavities covered over with membranes, functionally very much like our own eardrums — has been known for a long time, but a research group led by Dr. Jayne Yack, a professor and neuroethologist in the Department of Biology at Carleton University in Ottawa, Ontario, has discovered that at least one family hears with structures on the wings themselves.


The group's findings, published Oct. 17, 2018, in the journal Biology Letters, finds that the group of butterflies (2,500 species strong) known as nymphalids — you probably know a few of these by sight: monarchs, morphos, emperors and admirals are all in this family — have strangely swollen-looking veins on their forewings that actually help them hear. Butterfly wings are covered in thin, air-filled veins that provide stability for the delicate structures. One distinguishing feature of a nymphalid butterfly is the puffed-up vein on each of the top wings near the ear cavity. Yack and her coauthors hypothesized that, since the swelling was so close to the ear, maybe these veins assisted with hearing.

The researchers played sounds for the butterflies around the same frequency as a human voice while imaging their wings with lasers. The puffy wing vein of all 30 common wood nymph (Cercyonis pegala) butterflies they studied responded to the sound — and putting little incisions in the veins seemed to hamper their ability to hear — indicating that the structures are actually part of the butterfly's ears.

The researchers aren't sure what's going on with these special hearing apparatuses, but it could be that they help this group of butterflies tune into a wide spectrum of lower-frequency sounds.