Another Rare Moth Spotted at Glenorchy - Short-Lined Chocolate

This summer resulted in a real find as a Short-Lined Chocolate was discovered in the woods at Glenorchy. This dapper creature is a striking dark brown moth with diagonal thin white lines across the wing and a grayish wing border. The Short-Lined Chocolate, Argyrostrotis anilis, is a day flier, which is why it was out and about this July 1.

A search of the Ontario Insects website found only three references to this moth over the last 25 years.. These include a 1995 survey of Red Hill Valley by Bill Lamond, where its status was tentatively listed as Uncommon. Previously it was observed in 1984 at Pinery Provincial Park by Dr. Dale F. Schweitzer and again in 1991 by Alan Wormington near Westover and Hayesland. Local naturalists Bill McIlveen and his wife Irene have seen it only once, at Kerns Quarry in Waterdown. A web search indicates several recent beautiful photos of this species in the Ottawa area by Christine Hanrahan of the Ottawa Field Naturalists. Lynn Scott also maintains a site for moths observed in Ottawa. 

The rarity of this species is perhaps best underlined by a study being documented at the Discover Life website. This site has many excellent and unique projects related to biodiversity. Over the past two years John Pickering has been coordinating a project on moths. Two years of data collection at his site in Georgia has resulted in only 5 occurrences for this species out of a total of over 29,000 occurrences for 639 species.


According to Butterflies and Moths of North America, the Short-Lined Chocolate is a member of the family Erebidae, and superfamily Noctuoidea. This family was formerly a subfamily of Noctuidae but it now includes several other former subfamilies of Noctuidae. The Short-Lined Chocolate is one of seven members of the genus, all of which appear to be even less common, and is the only member of its genus found in Canada.

Butterflies and Moths of North America lists 16 verified observations, all in the U.S. The author of Moths and Caterpillars of the North Woods, Jim Sogaard, indicates he has only observed it only once.  NatureServe indicates distribution data is incomplete or has not yet been reviewed for this species.

Historically, The Biodiversity Heritage Library available through the Encyclopedia of Life website shows the Catalogue of the Lepidoptera Phalænæ in the British museum, 1913, as listing its range as the middle and southern states of Georgia, Florida, Kansas, and Texas. The Entomological News of 1925 listed it as rare in Georgia and Tennessee.

The most complete distribution map appears to be that available at the Moth Photographers Group website run out of the Mississippi State University. The Ontario sightings have all occurred in June, while at the southern end of its range in Florida it has been observed from February to October.

Map courtesy of Moth Photographers Group at the Mississippi Entomological Museum at the Mississippi State University

In recent years, the State of Connecticut has designated this species as a Landowner Incentive Program (LIP) At Risk Invertebrate Species, being of Special Concern at the State level. The LIP provides technical advice and cost incentives for private landowners to protect habitat for at risk species.

The Caterpillar HostPlants Database lists Malus, Sabatia, Prunus americana and Prunus domestica as food plants of the larvae. Other sources cite plants of the genus Sabatia (Rose Pink) and Prunus americana (American Plum). There are several species of Rose Pink, none considered to be extant in Ontario. The Common Rose Pink, Sabatia angularis, is a member of the Gentian family and is considered extirpated from Ontario, the only known specimen being obtained in the Hamilton area in 1865 according to the NHIC. In Missouri they are reported to feed on crab-apples and are said to produce at least two generations every year. Little else is known of the life cycle of this moth.

I could not help but reflect on this moth sighting. Why was it so uncommon? What was it feeding on? What plant species might it be responsible for pollinating? What would be the impact if it was gone? My research has convinced me that there is so much more to learn about the delicate creatures that inhabit our biodiverse world.