Considered one of the world’s smallest butterflies and the tiniest in North America, the Western pygmy-blue (Brephidium exilis) has a wingspan between 1.2 and 2 centimeters and can easily rest on a fingernail. Other butterflies under the Polyommatinae subfamily, also known as blues or gossamer-winged butterflies, may be smaller. Some researchers even argue that some species of moth are even tinier.
But despite the Western pygmy blue’s teeny size, it is resilient and can thrive in areas not normally found if it finds enough resources to support its life cycle. Butterflies are opportunists and will thrive in a habitat with necessary food sources for caterpillars. While some species are strictly limited to a host plant, others can migrate and will feed on various types of flowers. For this reason, there are several worldwide populations of the Western pygmy-blue.
Finding the Smallest Butterfly
When John Calhoun saw an image of a tiny coppery butterfly on iNaturalist, he was astonished. Calhoun is a research associate with the McGuire Center for Lepidopteran Biodiversity at the Florida Museum of Natural History and the butterfly, which he identified as a female B. exilis, was well outside its typical habitat.
