The story of the Colorado Hairstreak, Colorado’s state insect, began with a Fourth Grade Teacher in Aurora. Melinda Terry led her fourth grade class at Wheeling Elementary to the state legislature and insisted that this beautiful insect become an official symbol of the state. Their efforts spread across fourth grade classes in Colorado, and eventually, this butterfly overcame challenges to the state insect title, including a suggestion that the honeybee would be a better candidate. The Colorado Senate Bill 96-122 was passed and in 1996 and Colorado became the 37th state to officially declare a state insect - Hypauurotis chrysalis, the Colorado Hairstreak.

The Colorado Hairstreak is a montane butterfly, typically found in hills and canyons between 6500 and 9000 feet. They are recognized by their distinctive iridescent purple, blue, and black coloration when their wings are opened and the orange spots on their ventral side when their wings are closed. They have a small tail on their lower wings common to hairstreak, or Theclinae, butterflies and have a wingspan of less than an inch and a half at their largest.

Colorado Hairstreak (Hypaurotis crysalus). Photos by Gary Jue (BAMONA; www.butterfliesandmoths.org)

Male Colorado hairstreaks are very territorial and will defend their oaks from other butterflies of the same species. The adults can be found in the greatest numbers between July and August, and the butterflies only have one generation per year. Unlike the migratory monarchs and painted ladies, Colorado Hairstreaks tend to live within a few yards of their hatching place for their entire lives (Scott 1975). Even when startled, Colorado Hairstreaks tend to fly back into their home oak groves. Males are territorial and will chase each other as they patrol, flying in the canopy of the oaks looking for females. The males locate the females by their distinct purple coloration, though pheromones are also likely important for locating mates (Scott 1974).

Colorado Hairstreak Caterpillar. Photo by Todd Stout (BAMONA; www.butterfliesandmoths.org)

The Colorado hairstreak is completely dependent on the Gambel Oak (Quercus gambelii) throughout its life. The adults lay their eggs on oak twigs, and the eggs remain there throughout the winter until they hatch in the late spring. The caterpillars will then eat the young leaves of the oak until they pupate (Scott 1994). Once the adult emerges, the butterfly does not consume nectar from flowers but subsists entirely on sap and sugary secretions from oak galls (Wagner and Gagliardi 2015). They also may feed on honeydew, the name for sugary secretions from aphids and other insects. Sap and sugary secretions from insects are not as hydrating or as nutritious as flower nectar, so Colorado Hairstreaks have evolved behaviors to prevent dehydration and depletion of their energy stores (Scott 1994). These include the mostly sedentary lifestyles of the females and the tendency of the species to mate and lay eggs in the late afternoon and evening when summer rains are most likely.

Gambel Oak, Photos by Cory Maylett (Wikimedia Commons)

The Colorado hairstreak is a reclusive butterfly, typically spending its entire life in a single oak grove and never descending to feed on flowers, but they still have captured the imagination of both school children and entomologists with their unique behaviors and gorgeous coloration. Only one generation hatches each year and the adult hairstreaks can be spotted basking and looking for mates on late afternoons in July and August. Any time there is a grove of Gambel Oaks in the foothills of Colorado, a lucky observer can find Colorado Hairstreaks hidden in the branches waiting for the spring.

This is just one of the incredible animals you can discover through Butterfly Pavilion’s newest interactive exhibit—Colorado Backyard—opening March 23! It’s an opportunity to connect to the diverse life that surrounds us and get inspired to conserve all of our natural treasures in Colorado and beyond. Visit butterflies.local/exhibit/coloradbackyard to learn more.

References:
Chu, Janet R. and Stephen R. Jones. Butterflies of the Colorado Front Range: A Photographic Guide to 80 Species. Boulder: Boulder County Nature Association, 2011.

College of Agricultural Sciences. “Colorado Hairstreak (State Insect of Colorado).” In Colorado Insect of Interest series. Colorado State University, https://webdoc.agsci.colostate.edu/bspm/arthropodsofcolorado/Colorado-Hairstreak.pdf.

Scott, James A. "Flight patterns among eleven species of diurnal Lepidoptera." Ecology 56, no. 6 (1975): 1367-1377.

Scott, James A. "The interaction of behavior, population biology, and environment in Hypaurotis crysalus (Lepidoptera)." American Midland Naturalist (1974): 383-394.

Wagner, David L., and Benedict L. Gagliardi. "Hairstreaks (and Other Insects) Feeding at Galls, Honeydew, Extrafloral Nectaries, Sugar Bait, Cars, and Other Routine Substrates." American Entomologist 61, no. 3 (2015): 160-167.