Note: All links below go to external sites.
Hairstreaks are spiffy little butterflies that are named for the hair-like markings found on their underwings. Most have thin, twin tails (sometimes two pairs of tails) on the trailing edge of their hindwings, with bright blue/blue and orange eyespots nearby. Says Clarence Weed, writing about hairstreaks in Butterflies Worth Knowing (1922), “the slender tails, together with the enlargement of wings in back of them give the impression of a false head. Along with this unusual development of the wing is to be considered the fact that these butterflies nearly always alight head downward so that the false head, furnished with what looks like waving antennae, takes the place that would naturally be occupied by the true head.” Can you see a “face” here? Sometimes you see hairstreaks with a chunk of hindwing missing due to a predator thinking it was grabbing the tasty end of the butterfly and getting a less vital part instead.
They’re in the family Lycaenidae, which also includes the Blues/Azures, Coppers, and Harvesters, and they’re in the hairstreak subfamily Theclinae. These are not big, charismatic butterflies – Wisconsin species tend to be on the quietly-elegant side – but there are brightly-colored species in and near the tropics. Here’s a brief tour of some hairstreak species:
The more commonly seen Wisconsin hairstreaks are those that frequent bright flowers (especially butterfly weed) on sunny landscapes, and it’s not uncommon to find several species on one plant. But some of our species, including the Striped Hairstreak, are also found in the shade.
Look for Striped Hairstreaks (Satyrium liparops) around woody and swampy openings and edges and in grasslands from the Rockies to the Atlantic (including southern Canada). There are more of them the farther east you get. Although they are found over more than half of the continent, they’re never common within that range. “Scattered lightly over the landscape,” say the folks at the excellent Butterflies of Massachusetts website, “widely distributed although nowhere abundant.” They speculate that Striped Hairstreaks may have benefitted, at least initially, from the clearing of Eastern forests for agriculture in the 1600’s.
These are small butterflies – 1” to 1 ½” – with a long and a short set of tails, and brown upper wings (pictures of hairstreaks with their wings spread are hard to get), and their underwings have a scattering of wide, slightly darker bands that are bordered by parenthesis-like white stripes. The Edwards and the Hickory Hairstreaks have similar markings, so check your field guide.
They’re out and about in mid-summer. Males scan the landscape for females from perches in the vegetation, and if they see a rival, will battle by flying around each other in an upward spiral.
[Quick aside. When the BugLady was in grad school, her minor, briefly, was Ethology – Animal Behavior. In one lecture, the professor was describing bloodless standoffs between two male fish that puff up and flare their fins at each other. And the BugLady wondered – if you’ve never seen yourself in the mirror, and you (presumably) don’t have a sense of self-awareness, how do you know if your rival is bigger/tougher than you are, and you’d better back off? Is life one big game of chicken?]
Anyway, females lay eggs, one by one, on the twigs of the caterpillar host trees, which include some species in the rose family like apple, hawthorn, Juneberry, and cherry, plus some species in the heath family (blueberry) plus a few others. The eggs overwinter, and when they hatch the next spring, the caterpillars selectively eat the buds and flowers first (they are anthophagous), and then the tender leaves and fruit. That sounds dire, but there are too few of them to cause real damage, and there’s only one brood per year.
Adults feed on nectar from wildflowers and from the flowers of shrubs like staghorn sumac, viburnum, and meadowsweet, and from chinquapin oak. Butterflies of the Great Lakes Region tells us that “Early in the morning, they [adults] will sip dew from leaves as they bask,” and also that “The males perch low to the ground and are more sedentary and less interactive than the males of many hairstreak species. Adults spend a good deal of time walking on foliage and other perches rather than flying from place to place. On cool mornings, basking males may find curled leaves at the tops of small bushes…and lie nearly flat against the interior leaf surface with closed wings held nearly perpendicular to the sunlight. Here they absorb the maximal amount of solar radiation as well as energy from the leaf surface by radiation and conduction. This allows them to warm up quickly and defend their territory from other males…”
P.S. BugFan Molly shared this link with the BugLady recently. The BugLady knows nothing about it, and she is not on its board of directors. But – great pictures, and check out the store!