Coming or Going: Gray Hairstreaks

Which end is the head? To confuse potential diners, adult Hairstreak butterflies have slim tail hairs at the bottom of the hind wings that look like antennae, especially since the butterfly flicks them in a quivering motion. And both the top and under hind wings are marked with a distinctive orange “eye.” A predator, confused by this mimicry, may bite the tail-end and get a mouthful of dusty wing as the butterfly escapes with its head and abdomen intact.

Because Hairstreaks are not picky eaters, they have colonized many habitats throughout the new world, from southern Canada to northern areas of tropical South America. Our most common Hairstreak in the Kansas City area is the Gray, which has 3 broods each year so we see adults flying from April to October. They are relatively small with a wingspread from 3⁄4” to an inch, which is a shame since they are a spectacularly beautiful butterfly. The upper side of the wings shimmers in shades of blue caused by refracted sunlight, not pigment. The underside is a uniform soft pearl-gray with that orange eye and a few black squiggles.

We also have occasional glimpses of the Juniper Hairstreak, the only green butterfly in the United States. Several sightings in my yard converted me to a butterfly aficionado in 1994. Its caterpillar dines on Eastern Red Cedar, which is a Juniper, Juniperus virginiana. The green and chestnut adults nectar on small-flowers like the Mountain Mints and Queen Ann’s Lace. If you head east to the Ozarks, you should also see the similar Coral, Banded and Red-banded Hairstreaks.

Life Cycle

The pale green eggs are laid singly on the host plant flower and hatch in 4 to 6 days. The long-lived caterpillars dine for 3 to 4 weeks and then pupate in the leaf litter, which is also their winter hideout. Leave those leaves! By mid-April the adult emerges to find love with

LENORA LARSON Butterfly Maven

the males perching on shrubs to ambush passing females. These males are avid puddlers, collecting minerals to include in their spermatophore, which is passed to the females when mating. The adults live up to ten days and prefer small blossoms for nectaring. I see them most frequently on my Celosia.

Feasting on Flowers

The small slug-like caterpillar looks velvety with short hairs covering its body. While most caterpillars eat leaves, the Gray Hairstreak caterpillar feasts on flowers. This is not a restricted diet with over 20 plant families, representing over 50 species, serving as host plants. In our area, the legume family seems to be its favorite and occasionally it even eats legume fruits such as pea and bean pods. I’ve also found the caterpillar munching on Lythrum and Rose Verbena flowers, which dye the caterpillar a lovely rose color. When dining on my purple pole beans they are a soft violet, and pale green when eating clover blossoms. In the south the Gray Hairstreak caterpillar is called the Cotton Square Borer because it dines on young cotton bolls.

Myrmecophily

Occasionally the caterpillars are guarded by ants, which stroke them to release the sugary honeydew. This activity, called myrmecophily or “ant-loving,” can be cited as an example of animals practicing animal husbandry. That is, the ants keep herds of Gray Hairstreak caterpillars, grooming them, “milking” them, and protecting them from predators.

Summary

You don’t have to be big to be beautiful! Although Hairstreaks are huge compared to 50 percent of our native bees, which are smaller than a grain of rice! Since Gray Hairstreaks are so flexible in their habitat and feeding requirements, you are almost sure to see them in your garden and on butterfly hiking trips. Enjoy!