Strymon istapa clenchi

Mallow Scrub Hairstreak

This uncommon hairstreak was described by G. Austin and J. Emmel as a subspecies of Strymon columella in the 1998 Systematics book. It flies in "extreme southern California" and into Nye Co., Nevada, southern Arizona and into Baja California, Mexico (and possibly into mainland Mexico as well, the authors say). The type locality is Blythe. The flights are from early spring all the way to November. This hairstreak feeds on mallows in the larval stage. Malvella leprosa is mentioned in the description, but Gordon Pratt says it prefers Hibiscus denudatus in the desert, where it can use Sphaeralcea species as well.

The life cycle of this butterfly was described by John Comstock and Charles Dammers in a 1935 article in the Bulletin of the Southern California Academy of Sciences ("Notes on the Early Stages of Three Butterflies and Six Moths from California," v.34, pp.120-123). I've excerpted in below from the copy on the BHL website.

Strymon istapa clenchi - Mallow Scrub Hairstreak
Strymon istapa clenchi seems to be on the wing most often either in April or in the fall, though it can fly in the summer as well. I'm not sure about the details of the timing of the broods. This one was among several I saw at Guajome Regional Park in Oceanside on September 20, 2020.
Strymon istapa clenchi - Mallow Scrub Hairstreak
Another Strymon istapa clenchi, same day as above.
Strymon istapa clenchi - Mallow Scrub Hairstreak
This is the rarely-seen Strymon istapa clenchi, which I chanced upon while hiking Cactus Spring Trail on March 21, 2014.
Strymon istapa clenchi - Mallow Scrub Hairstreak
Showing a bit of the dorsal side. I'm not sure what is going on with the pale spot on the wing, and it flew off before I could see the left wing.
Strymon istapa clenchi - Mallow Scrub Hairstreak
Same trail, next year: April 5, 2015. Just saw one on this day. This one oviposited on Apricot Mallow buds.
article about the life cycle of Strymon istapa clenchi - Mallow Scrub Hairstreak
I found this brief 85-year-old article on the life cycle of this butterfly valuable. I think it's safe to say Comstock was the leading authority on butterflies at this time in California, and Dammers was a fantastic illustrator.

©Dennis Walker