Male. San Mateo State Park, Orange County, CA. 2-29-12. © Peter J. Bryant.
Thanks to Bob Gorman for discovering this colony.

Great Purple Hairstreak

Atlides halesus corcorani

Lepidoptera: Lycaenidae

Like other hairstreaks, this butterfly has colored tails that are thought to attract the attention of predators to the tail instead of the head. This gives the butterfly a better chance of survival, but it means that many individuals found in the wild are missing some of those posterior wing parts. When at rest, hairstreaks often move their wings against each other, making the tails oscillate (see video) and further increasing the chances that the predator will be attracted to the tail rather than the head. Butterfly wings, including the tails, have no internal muscles but are moved by muscles inside the thorax.

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Characteristics: Our largest hairstreak. Dorsal wing surface brilliant iridescent blue-purple and gray-brown. Ventral wing surfaces with red markings near body. Forewing length: 18-20 mm (male) or 20-22 mm (female).

Similar Species: This species will not easily be mistaken for any other butterfly.

Habitats, Behavior: The Great Purple Hairstreak frequents tree tops, and rarely comes within reach of a net. The Villa Park specimens were captured on blossoms of the shrub Lepidospartum squamatum, a fairly compact bush with yellow flowers appearing around late August into September in the county's mountain canyon washes.

Distribution: Our Orange County records are from Trabuco Canyon, Corona del Mar, Fullerton, Orange and Villa Park. This butterfly is usually captured in the vicinity of the larval foodplant.

Flight Period: This beautiful butterfly is said to be multiple brooded, flying from March to October (Emmel and Emmel, 1973). The summer and fall broods are apparently far larger than the spring brood although the butterfly is generally rarely captured even during peak flight periods.

Larval Foodplant: In Orange County, Mistletoe, probably Phoradendron tomentosum ssp. macrophyllum, which is commonly found growing on California Sycamore (Platanus racemosa). Sycamore grows frequently in streambeds and moist canyon bottoms, and trees with mistletoe infestations are easily discernable.

Other Remarks: The Great Purple Hairstreak is likely to occur wherever Sycamore and its parasite mistletoe occur (e. g. lower San Juan Creek, Silverado, Modjeska, Santiago, and Trabuco Canyons, Irvine Park, etc.) although the butterfly occasionally strays from breeding sites. Perfect specimens are often obtained by collecting the pupae, which are found wrapped with dead leaves, etc., attached to the bases or crevices of the sycamore, and waiting for the adults to emerge. The best trees to examine are the ones with heavy mistletoe growth and little or no organic material around the base of the tree (which would make the pupae harder to find). Such trees are usually found in rocky creek beds. The pupae, however, are often highly parasitized and only a few of these beautiful creatures may emerge from a large number of collected pupae. Our knowledge of butterfly parasites is so poor for many species that the parasites should be retained along with the host material, and kept or given to an institutional collection where such material can be best utilized.

From Orsak, L. J. (1977). The Butterflies of Orange County, California. Center for Pathobiology Miscellaneous Publication #3. University of California Press, New York. 349pp.

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