There’s a good chance you can spot this little blue-gray butterfly at Mount Pisgah—or in your yard—these days. Here are some reasons the Gray Hairstreak is worth a closer look.
Strymon melinus is small, with a wingspan of 3/4ths of an inch to just over an inch. The name “hairstreak” comes from the hairlike lines of markings on the wings of the butterflies in this sub-family. It’s also apropos of the hair-like tails at the wing-ends.
The tails on the Gray Hairstreak, accompanied by the nearby orange and black spots, are thought to mimic eyes and antennae. The insects tend to perch with their tails in the air, and then rub their wings together, giving the appearance of twitching antennae. I have found a hairstreak with the back of its wings gone; perhaps bitten off by a predator that was aiming for the head, but ended up with a mouthful of scales.
The Gray Hairstreak lives across most of North America. That’s because it can get nectar from, and lay eggs on, a wide buffet of common plants, from clover to mints (nectar) to peas and mallow (caterpillar hosts).
I’ve read about at least three ways to tell a male gray hairstreak from a female, but I don’t have enough photos to test them out. According to Britannica online, the male’s forelegs are reduced, but the female’s are fully developed. BugGuide says the male’s abdomen is orange–another source specifies that males in the summer have orange near the end of the abdomen. The BugLady says females have wider forewings.
Hairstreak caterpillars are interesting in their own right. They are slug-shaped and can vary in color from green to pink. They also secrete a honeydew that attracts ants. I haven’t found any larvae yet, but I’ve read it can be easiest to look for ant activity, then look for the caterpillars.
See more of Karen’s work here.
P.S. For bug-fan Tamara from the last insect walk: The nymph you found was likely an early-stage green stink bug.
BugGuide’s page: https://bugguide.net/node/view/579. Accessed 8/25/22.
The BugLady’s page: https://uwm.edu/field-station/gray-hairstreak-butterfly/. Accessed 8/25/22.
Fun notes on how to raise these butterflies: http://www.raisingbutterflies.org/gray-hairstreak/. Accessed 8/25/22.