Colias philodice

Clouded sulphur
	Male specimen
Conservation status
	; Least Concern (IUCN 2.3)
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Class:	Insecta
Order:	Lepidoptera
Family:	Pieridae
Genus:	Colias
Species:	C. philodice
Binomial name
	Colias philodice; Godart, 1819

Colias philodice, the common or clouded sulphur, is a North American butterfly in the family Pieridae, subfamily Coliadinae.

Description

This species is a typical member of the genus. Both genders typically have pale yellow wings above with no traces of orange, unlike its close cousin the orange sulphur which may also be yellowish. Males have clean borders, while females have yellow dots within this region. Females sometimes exhibit a white form known as alba.

The underside of the male's wings is yellow while the female's is yellow or greenish-white, and both have a doubled hind wing spot trimmed in brownish-red. The hindwings show a series of 4 small red spots along the outer third portion, a trait that distinguishes the other North America species such as Colias interior, with exception of the orange sulphur which also shows them. Its wingspan 32 to 54 mm.^[1]

Form alba

This species has white form alba which can be very common in some populations, while rare in others. It can be confused with other white form Colias particularly that of Colias eurytheme. It can often be told by the border pattern of both wings, though some individuals are impossible to separate without the presence of other "normal" specimens. Though they differ in flight style, white form Colias may be confused with other pierids such as Pieris rapae and Pontia protodice. ^[2]

White form males are also known, but they are exceedingly rare in this species. ^[3]

Habitat

This butterfly may be encountered in fields, lawns, alfalfa or clover fields, meadows, and roadsides. Swarms of these butterflies will congregate at mud puddles. They range over most of North America with the exception of Labrador, Nunavut, and northern Quebec.^[1]

Nectar plants

Clouded sulphurs nectar at flowers such as milkweed (Asclepias sp.), butterfly bush (Buddleja sp.), coneflower (Dracopis, Echinacea, and Rudbeckia), alfalfa (Medicago sativa), dandelion (Taraxacum sp.), clover (Trifolium sp.), and tall verbena (Verbena bonariensis) and many more.

Host plants

Ground-plum (Astragalus crassicarpus), Platte River milk-vetch (Astragalus plattensis), soy-bean (Glycine max), deer-vetch (Lotus spp.), alfalfa (Medicago sativa), white sweet-clover (Melilotus albus), black locust (Robinia pseudoacacia), white clover (Trifolium repens), red clover (Trifolium pratense), vetch (Vicia spp.)

Life cycle

The pale yellow eggs are laid singly on the host plants. The eggs turn red after a few days, then turn gray just before they hatch. The young larvae will eat one another. The larva is green with a white stripe running along each side of the body. The white stripes may contain bars or lines of pink or orange. The green chrysalis hangs up right by a silken girdle. Just before eclosion, the chrysalis turns yellow with a pink "zipper".