Colias philodice

Clouded sulphurs are widespread across North America in the Nearctic region, occurring from the Arctic south to Guatamala. The subspecies Colias philodice vitabunda is found only in northern British Columbia to the Alaskan tundra. (Opler and Krizek, 1984; Scott, 1986)

Clouded sulphurs are best adapted to open areas such as moist meadows, lawns, and alfalfa and clover fields. (Opler and Krizek, 1984; Scott, 1986)

Adults are yellow, with submarginal dots on the undersides of the hindwings. There is one silver spot in the center of the hindwing with two red rings around it, and often there is a satellite spot. Females have a narrow black forewing border with light spots. The subspecies C. philodice vitabunda has mostly white females. The average wing measurement of female clouded sulphurs is 2.6 cm, and ranges from 2.2 cm - 3.1 cm; males range from 2.2 cm - 3.2 cm with an average of 2.4 cm. Clouded Sulphurs may hybridize with orange sulphurs (Colias eurydice). (Opler and Krizek, 1984; Scott, 1986)

Clouded sulphur eggs are cream colored when first deposited, then turn crimson in a day or two. The larvae are green, sometimes with pale yellow sides, with raised points and a faint green mid-dorsal line. There is a white lateral band on the larval body. (Scott, 1986)

The pupa is green with yellowish white and black mottling and a yellow band. (Scott, 1986)

The last larvae of the year are reported to overwinter in the third stage (sometimes fourth). Other reports state that the clouded sulphurs overwinter as crysalis. (Opler and Krizek, 1984; Scott, 1986)

The mating system of clouded sulphurs has been well documented. As the male flies toward the female, she will land and the male will proceed to buffet his wings against her body, releasing pheremones that are produced in a gland in a patch on the upper surface of the hindwing. If the female detects the pheremone and it activates her responses, she will lower her abdomen and the pair will mate. Females will also approach males when they are ready to mate. (Scott, 1986)

As a male clouded sulphur flies toward a female, she will land and the male will proceed to buffet his wings against her body, releasing special communication chemicals (pheromomes) that are produced in a gland in a patch on the upper surface of the hindwing. If the female detects the pheremone and it activates her responses, she will lower her abdomen and the pair will mate. Females will also approach males when they are ready to mate. (Scott, 1986)

Females that are less than one hour old cannot differentiate between the pheremones of clouded and orange sulphurs. It is during this time that the most frequent hybridization occurs. Usually, only sterile females are produced. When there is a female clouded sulphur and a male orange sulphur, viable offspring are produced. (Scott, 1986)

There are several broods of clouded sulphurs from spring until fall, the actual number depending on the latitude. Colias philodice vitabunda flies mainly from June until mid-July. (Opler and Krizek, 1984; Scott, 1986)

Butterflies do not exhibit parental care.

In Colorado, clouded sulphurs lived an average of 2-3 days, with the longest surviving 2 weeks. In Colorado, females lived 17 days and males 24 days (average 2-7 days). In Virginia, males lived for 17 days. (Scott, 1986)

The flight pattern of clouded sulphurs is fairly rapid and sometimes erratic. They usually stay within one meter of the ground. Clouded sulphurs are well known for their mud-puddling behavior, - gathering in groups to sip from the mud in wet places. Most believe butterflies are seeking out salts and minerals from the water. (Iftner, et al., 1992)

Their home ranges are from 40 to 100 acres in size. (Scott, 1986)

Clouded sulphurs use visual cues and pheremones to communicate with each other. (Scott, 1986)

The larval foodplants for clouded sulphurs are numerous, and most are members of the legume family. Species include milk vetch (Astralagus), clovers (Trifolium), wild indigo (Baptisia tinctoria), wild pea (Lathyrus leucanthus), trefoil (Lotus), lupine (Lupinus perinnis), alfalfa (Medicago), white sweet clover (Melilotus alba), and vetch (Vicia). (Scott, 1986)

Nectar plants are varied and include alfalfa (Medicago sativa), clovers (Trifolium), milkweed (Asclepias), self-heal (Prunella vulgaris), and teasel (Dipsacus sylvestris). (Scott, 1986)

Predators of all life stages of butterflies include a variety of insect parasatoids. These wasps or flies will consume the body fluids first, and then eat the internal organs, ultimately killing the butterfly. Those wasps that lay eggs inside the host body include species in many different groups: Ichneumonidae, Braconidae, Pteromalidae, Chalcidoidea, Encyrtidae, Eulophidae, Scelionidae, Trichogrammatidae, and others. Trichogrammatids live inside the eggs, and are smaller than a pinhead. Certain flies (Tachinidae, some Sarcophagidae, etc.) produce large eggs and glue them onto the outside of the host larva, where the hatching fly larvae then burrow into the butterfly larvae. Other flies will lays many small eggs directly on the larval hostplants, and these are ingested by the caterpillars as they feed. (Scott, 1986)

Most predators of butterflies are other insects. Praying mantis, lacewings, ladybird beetles, assasin bugs, carabid beetles, spiders, ants, and wasps (Vespidae, Pompilidae, and others) prey upon the larvae. Adult butterflies are eaten by robber flies, ambush bugs, spiders, dragonflies, ants, wasps (Vespidae and Sphecidae), and tiger beetles. The sundew plant is known to catch some butterflies. (Scott, 1986)

There are also many vertebrate predators including lizards, frogs, toads, birds, mice, and other rodents. (Scott, 1986)

Clouded sulphurs function as prey for a variety of species, and also serve as minor pollinators.

Clouded sulphurs provide aesthetic benefits to humans, and many people enjoy watching them.

This species is sometimes thought of as a pest species due to the larvae feeding on crop plants.

This species is common rangewide and receives no special protections.

Clouded and orange sulphurs exhibit chromosome polymorphism - genes controlling female mate choice, male pheremones, male ultraviolet reflection (in orange sulphurs only), orange or yellow color, width of the black forewing border size, and the rate of development are all located on the X chromosome, termed a "supergene". It has been found that nearly all differences between the two species occurs on this X chromosome. Female hybrids preferably mate with males of their fathers' species (orange sulphurs), thus the X chromosome stays with the appropriate species. (Scott, 1986)

The genus Colis is believed to be named after Kolias, the epithet of Venus (Greek mythology). The species may have been named after the sea nymph Phyllodoce. (Opler and Krizek, 1984)

Colias philodice philodice has had several common names, including clouded sulphur, bordered yellow butterfly, common sulphur, yellow clover butterfly, yellow sulphur, mud puddle butterfly and yellow butterfly. The subspecies C. philodice vitabunda is known as the lively clouded sulphur. (Maynard, 1891; Miller, 1992)