October 24, 2012 8 Comments
After years in the field looking for insects, one develops an eye not only for recognizing insects but also recognizing when something doesn’t look quite right. That happened to me early this past September at a spot along the Mississippi River in southeast Missouri where I had stopped during late afternoon to look for diurnal species of tiger beetles and then man a blacklight in the evening for nocturnal ones. It was still daylight as I walked along the edge of rank growth bordering the upper banks when a small, reddish “cluster” on a seed head in a stand of tall grasses caught my eye. I didn’t know what it was when I saw it, but I knew it was something ‘out of place.’ My first, cursory thought was that somehow the spent anthers of the now-seeding grass had gotten caught in a tangle, but I must have still had doubts because I looked closer anyway. Just then the “cluster” moved, and I then recognized what I was dealing with—an Emerald moth (Synchlora sp.) caterpillar. Caterpillars in this genus are remarkable for their habit of adorning their bodies with bits of the plants upon which they feed. I am, however, a beetle man and thus admit to being completely unaware of their existence until last summer when Alex Wild featured one of these as a Monday Night Mystery. I wondered then, “Why haven’t I seen one of these before?”, and now I know why—because they are extremely well camouflaged!
Realizing what I had, all efforts to look for tiger beetles were suspended (I hadn’t seen anything after ~30 minutes of looking anyway), and I broke out the 65mm lens to get the most of this small but remarkable looking insect. I took more than 50 shots, trying different backgrounds, angling the grass stem in different positions, and hoping with each shot that I had captured the larva in full profile, completely in focus, and in the midst of that magical loop. I was sure I had that “perfect” shot when I got home and anxiously fired up the computer to get a better look at the photos. My optimism began to drop, however, as I scanned through each successive photo and continued to not encounter that one photo that would cause me to say “Yes!” Exposure? Check. Composition? Check. Lighting? Check. Focus? Er… crap! The problem was pervasive throughout the entire set, and in the end, I have only this one photo that comes anywhere close to what I had envisioned while I was taking the photos. It’s a shame, because I love everything else about this photo. The cause of the problem is the very thing that makes the larva so remarkable—its adornments. The spent anthers project off the larva in all directions, adding considerable dimensionality to the subject and surpassing the depth-of-field capabilities of my lens. If the subject was in focus the forward projecting anthers were not, and if the anthers were in focus the subject was not. If I had realized in the field what was going on, I would have not gotten in so tight and cropped as appropriate during post-processing. Live and learn!
Although 12 species of Synchlora are found in North America, only one—Synchlora aerata (Wavy-lined Emerald)—is widespread in the eastern U.S. However, a number of other species are found in the southeastern U.S., and for all intents and purposes the Mississippi Lowlands of southeastern Missouri are the south (culturally as well as biogeographically!). As a result, a generic ID is the best that can be done for this larva.
Copyright © Ted C. MacRae 2012