The smallest buttefly in the world?
Often said to be the smallest butterfly in the world, the Western Pygmy blue butterfly (Brephidium exilis) measures about 15 to 19mm (0.62 of an inch) across the wings. Although fairly widespread in Southern USA, many people walk right by these tiny blues without even noticing. The species often occurs in large numbers, but they fly very close to the ground with a slow flight. Their habitat includes alkaline areas such as deserts, salt marshes and wasteland.
The butterfly's upper side is a copper brown, with dull blue at the bases of both wings. The underside of the bottom wing is a copper brown with white at the base; 3 small black spots near the base and a row of black spots on the outer margin. The female is larger then the male, and less blue.
Despite its size and seeming fragility, during the summer months the Western Pygmy blue flies north to lay its blue-green eggs. These eggs hatch into light green to cream-white caterpillars that feed on pickleweed, saltbush and pigweed. As an adult the butterflies eat flower nectar.
This is one of the only butterflies whose populations have probably increased with the interference of man and the introduction of weed, such as the tumbleweed, which is used by the Pygmy blue as a larval food source.
Although the blue is often claimed to be the smallest butterfly in the world, there is a type of butterfly in South Africa called Barber's Blue, where the male can be as little as 6 mm in size.
(On every website I found, the Western Pygmy was said to be the smallest, and I found nothing about this Barber's Blue.)
Sources:
www.insects.org/entophiles/lepidoptera/lepi_004.html
www.npwrc.usgs.gov/resource/distr/lepid/bflyusa/ca/228.htm
www.wildlifewebsite.com/butterflies/ smallest-butterfly.html
www.enchantedlearning.com/subjects/ butterfly/allabout/Extremes.shtml
Photo:
www.insects.org/entophiles/lepidoptera/lepi_en004.html