IN SEARCH OF THE FRENCH-GRASS FLOWER MOTH

(SCHINIA NR-JAGUARINA)

Schinia nr-jaguarina (French-grass flower moth or Sainfoin flower moth). The scientific name used here is just a placeholder used on Bug Guide (https://bugguide.net/node/view/1638554) since this species has not been officially named at this point. Oh yeah, and I totally made up those common names.

Anyway, here I am, an Illinois botanist in search of a rare moth caterpillar. Who would have thunk it? I can’t hardly believe it either. As far as I remember, I first became aware of this rare moth and its striking caterpillar about five or six years ago after seeing a blogpost by Jim McCormac (https://jimmccormac.blogspot.com/2012/07/interesting-moth-new-to-science.html). I have searched for it a few times in the past, but this year I decided to get serious. Other Schinia flower moths are reliably found on specific host plants and as a botanist I know that I can find this caterpillar’s host plant, Orbexilum onobrychis (French-grass or Sainfoin). Huh, so maybe it does make sense for a botanist to look for a flower moth. French-grass is not a common plant but it is distributed widely across 13 eastern U.S. states and Illinois is at the center of its distribution (See distribution map from BONAP).

Orbexilum onobrychis (French-grass or Sainfoin)

 As an Illinois botanist, I know of several central Illinois populations for French-grass. Also, a few friends have kindly alerted me to additional locations (Thanks, Matt, Matt, and Jared!). One of these new to me sites is just a short 20-minute drive from my home. So close that I could not pass up the opportunity, so this past Friday I took a much-needed day off work and went to check it out. This site is a remnant prairie that was both protected and neglected because of the adjacent railroad. In the past, several local prairie heroes from Champaign and Vermilion counties have looked after high-quality sections of this prairie corridor. Now the railroad is gone and replaced by a bike path. This site, although degraded, is once again receiving some love, this time by the local Champaign County Forest Preserve District (CCFPD) staff.

Distribution map from BONAP.

I was able to park close to the bike path prairie corridor, at a local farm access. With my camera in hand, I started walking down the bike trail, with my expectations low. After all, this caterpillar which feeds on a reasonably common plant remained unknown for hundreds of years. Surely it won’t be here. Not today. At first I was just passing the time sweating and taking photos of grass inflorescences and weedy plants that came in along the new path, but it didn’t take long to find a nice sized population of French-grass. The nice thing about French-grass is that it is a large showy plant and it forms extensive colonies. It is not necessarily an easy plant to find since it is absent from most of what seems to be suitable habitat but, if you know of a location, it is an incredibly easy plant to notice and not one that you are likely to just walk by.

Warty legumes of Orbexilum onobrychis.

So here it, a nice population of French-grass running for tens of feet parallel to this narrow corridor between U.S. 150 and the bike path. The plants are in flower so, even though I do not see any caterpillars right off the bat, I start taking photos of French-grass flowers. They are beautiful! Racemes full of small blue-purple legume flowers. Then I notice the fruit has started to develop, a somewhat pointy and odd-shaped warty legume. I guess I’ll take some photos of those too. I got a little distracted and started chasing some grasshoppers and other insects around the plants, some I’m able to catch up to and photograph and others just provide me with some exercise. Then, right in front of me, I see my first caterpillar of Schinia nr-jaguarina, the French-grass flower moth. It’s maybe about two centimeters long, yellow with dark black spots in lines down its body. A striking little caterpillar for sure. After a little more searching, I saw a few dozen caterpillars, most very small at this time.

             

At this point, it seems this amazing little caterpillar has been found in Ohio, Indiana, Kentucky, Illinois, and Missouri and I believe this is at least the fourth record in Illinois. Hopefully, I'll be able to find a few more locations while the caterpillars are still out and about.

Success came easy this time but it was still sweet and I was overjoyed to have finally encountered this little mystery organism. Next year, I want to get to the site earlier to try to photograph some mature moths. Onward to the next search!