Skullcap Skeletonizer

 

 

 

SSM - INaturalist CC

Tonya Smith sent me this picture of a beautiful little moth which she identified on INaturalist as the skullcap skeletonizer moth (SSM), Prochoreutis inflatella.  Downy skullcap was growing at the Springfield Lake Boathouse right where she discovered the little SSM. The moth's wings have beautiful silver streaks with a wingspan less than half an inch. Adults are said to be on wing from June to September. but this was photographed in May.  There are several generations per year.

Downy Skullcap-Wikimedia

Downy skullcap, Scutellaria lateriflora, is a pretty wildflower in the mint family.  It is showy, a nice addition to a garden.  It also is packed with a lot of chemical punch. It produces many chemicals which have been promoted as herbal medicines for sleep or a mild sedative.  Cherokee women may have used it to induce abortion.  Because the foliage is bitter-tasting and possibly toxic, mammalian herbivores usually don't bother eating it.

Leaf skeletonized by SSM - Moths of North Carolina

The SSM larvae feed on Scutellaria species, including downy skullcap. They skeletonize the leaves, bending the leaf upwards and the edges together. They feed under slight webbing. The first larvae appear in March, only shortly after the host plant begins growth.  Pupation occurs in a fusiform, multi-layered cocoon of white silk. 

Skullcap Caloptilia leaf mines*

Another moth with a taste for skullcaps is Caloptilia scutellariella, the skullcap caloptilia moth. These larvae are leafminers, spending their childhood inside the lower side of the leaf epidermis.  They then crawl out to pupate in the rolled up leaf base.

*Leafminers are cool.  Spending their infancy crawling between the upper and lower surfaces of a leaf, they leave a trail of frass.  Charley Eiseman's Leafminers of North America is encyclopedic and takes no shelf space as a continually updated huge PDF, highly recommented.