Least Skipper Butterfly – Ancyloxypha numitor

Least Skipper Butterfly – Ancyloxypha numitor
Family: Hesperiidae – Skippers
/ Subfamily: Hesperiinae – Grass skippers
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Live adult skipper butterflies photographed at Winfield, Illinois, USA.

Least Skipper Butterfly - Ancyloxypha numitor

Least Skipper takes nectar from ox-eye daisy

The least skipper is a weak flyer often found flitting about in low grass and foliage throughout the US east of the Rocky Mountains. They can be incredibly abundant in some years. I find them most often near watercourses or damp, low lying areas.

Identification: Antennae are short, banded with black and white alternating. Upper side of forewing is orange with a wide, diffuse black border at the outer margin; hindwing is yellow-orange with a wide black margin. Underside of forewing is black with orange borders at the tip and leading edge; hindwing is yellow-orange.
Life cycle: Males patrol for females with a low, fluttery flight through grassy areas. Females lay eggs singly on grass blades. Caterpillars feed on leaves and rest in nests of rolled or tied leaves. Third- and fourth-stage caterpillars hibernate.

Flight: Three broods from May-October in most of the range, four broods from February-December in the Deep South and Texas. Wing span: 7/8 – 1 1/8 inches (2.2 – 2.9 cm). Caterpillar hosts: Various grasses including marsh millet (Zizaniopsis miliacea), rice cutgrass (Leersia oryzoides), and cultivated rice (Oryza sativa).

Adult food: Flower nectar from low growing plants such as wood sorrel, swamp verbena, pickerelweed, chickory, and white clover. Habitat: Moist or wet open places with tall grasses, marshes, ditches, slow streams, hillsides, or old fields with tall grasses. Range: Nova Scotia west to southern Saskatchewan; south through the eastern states to Florida, the Gulf states, Texas, and SE Arizona. Strays to central Colorado. [1]

3 least skippers on dandelion

Do least skippers love dandelion?

All adult true skippers have six well developed legs. Their eggs are tiny, usually less than .1mm. Most skipper caterpillars are green and tapered, and the neck appears constricted. The caterpillars weave silk and leaves into a daytime shelter for protection. Most pupate in loosely woven cocoons. The chrysalises are often coated with a powder or bloom. Chrysalis and caterpillars may overwinter.

Skipper butterflies can be divided into five subfamilies:

  • Pyrginae, or spread-wing skippers. These butterflies bask with their wings spread open flat, although there are a few that sit with the wings folded over their back. The cloudy wings sit with their wings partly open. Most spreadwings are patterned in gray, black and white. Caterpillars feed on many different types of plants, especially legumes.

  • Grass Skippers, subfamily Hesperiinae constitute the largest grouping, and perhaps the most challenging for those seeking to identify specimens. They are smaller than the spread-wing skippers, and many are patterned with yellow, orange and black. These erratic flyers sit with their forewings and hind wings at different angles – I think the configuration resembles an F-15 Eagle fighter jet. Grass skipper larvae feed mostly on … guess what? Yep. Grasses.

  • Giant Skippers, subfamily Megathyminae includes the largest skippers. These are rare butterflies, even where there host plants, the Agaves and Yuccas are common. They are very fast and powerful flyers.

  • Skipperlings, subfamily Heteropterinae includes only a handful of small species living in the north and west. They lack the narrow extension (apiculus) of the antenna club. Many skipperlings sit with the wings open flat. They are often lumped into the grass skipper family. Note: Some skippers are called skipperlings but do not actually belong to this subfamily.

  • Firetips, subfamily Pyrrhopyginae. Only one species of this group inhabits North America: the Atraxes skipper.

Least Skipper Butterfly takes nectar at clover flower

White clover
1. Opler, Paul A., Harry Pavulaan, Ray E. Stanford, Michael Pogue, coordinators. 2006. Butterflies and Moths of North America. Bozeman, MT: NBII Mountain Prairie Information Node.

Order Lepidoptera, which contains both butterflies and moths, includes at least 125,000 known species including 12,000 in North America. Butterflies are revered for their brightly colored wings and pleasing association with fair weather and flowers.
Learn to identify many of the American Midwest's common species through descriptions and large diagnostic photos of live, wild specimens.
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