March, 2007

Juniper Hairstreak

Hairstreaks are small and often inconspicuous butterflies. My favorite in this group is the juniper hairstreak (Callophrys gryneus or Mitoura grynea), with wings sporting green and rust colors highlighted by white markings. These butterflies are also called cedar hairstreaks or olive hairstreaks. There is some confusion about the taxonomy of this species, as it may have several subspecies over its large range or actually be a complex of more than one species, with some populations using different host trees and some variation in wing markings. Only about an inch in size, these insects are small, but their intricate wing patterns make them stand out, especially when the sunlight catches the green scales. Adults are often seen at flowers throughout much of the spring and summer, as well as on their larval host plant, juniper trees. When the butterflies rest on juniper branches, they blend right in, and the caterpillars, which eat the tips of the trees' prickly needles, are almost invisible due to their excellent camouflage. While the adult butterflies occasionally visit our flowers, especially rosemary, and are easy to spot, the larvae are almost never noticed because they are so small and well hidden. I was therefore quite surprised to actually find a caterpillar on one of our small juniper trees. I was playing ball with the dog and standing next to the tree, when I glanced at the nearest leaf and saw the larva. After I went inside to get my camera, it took quite a bit of searching to once again locate the obscure little bug, even though it had not moved at all.