This past weekend my good friend and long-time collecting partner Rich and I visited one of our favorite insect collecting spots in all of Missouri – Victoria Glades Conservation Area. Together with an adjacent parcel owned by The Nature Conservancy, these represent one of the finest remaining examples of the glades – more properly called xeric limestone prairies – that once extended in an arc through Jefferson Co. south of St. Louis on south and west facing exposures of dolomitic limestone1.
1 For a more detailed description of the geology and natural history of these glades, see my post The Glades of Jefferson County.
Spring was late this season, with cool and wet conditions persisting into the early part of May. During the past two weeks, however, it has warmed and dried considerably (too much, almost), and thus the cacophony of life has begun in earnest. Still, despite the heat, we found the abundance of insects rather sparing, which in combination with the suite of wildflowers that were seen in bloom gave a feel of early spring (I mentioned to Rich that it “seemed like May 10th”). There were a few good species to be found though, the first being a single Agrilus fuscipennis, beaten off of its host persimmon (Diospyros virginiana). Continued beating of persimmon turned up little else, at which point I turned my attention to the post oak (Quercus stellata) trees lining the margins of the glades. The first couple of branches that I whacked turned up little of interest, but an “ant” that fell on my sheet from the third branch gave me pause – it was a little “too big”, and the manner it which it scampered across the sheet was a little “too urgent” and “too halting”. When I looked at it more closely, I realized that it was, of course, not an ant at all, but a jumping spider (family Salticidae), and more specifically a species in one of several genera within the family that are known for their striking mimicry of ants.
I have long wanted to photograph one of these gems, having seen them once or twice before but thus far not successful in photographing them. In this particular case, I had the advantage of somebody to help me, so I coaxed the spider onto a stick and had Rich hold it while I got my camera ready. Unfortunately, the ant… er, spider just kept running up and down the stick from one end to the other, forcing me to repeatedly grab the stick on alternating ends with one hand after the other (and quickly or it would run onto my hands!) and never really having an opportunity to attempt some shots. After a time of this, I decided to coax it onto a leaf instead to see if the larger, flatter surface might be of some help. It really didn’t, though, as the ant JUST. WOULD. NOT. STOP. RUNNING! Eventually, I resorted to simply trying to track the spider through the lens – holding the camera with my right hand and the leaf with my left, and firing shots whenever I thought the spider might be even close to in focus. I can be patient when photographing insects (and their kin), but this spider certainly tested my limits, and I eventually ended the session not at all confident that I had any usable photos. To my surprise, I managed to get one image (above) that wasn’t half bad and another that was at least serviceable (below – focus a bit too much in “front”).
As far as I can tell, this individual is a species of the genus Peckhamia, which Cutler (1988) distinguishes from the related genus Synageles by the carapace being more convex in the cephalic area and sharply declivous (downward sloping) behind the third row of eyes. The individual in these photos seems to agree with these characters, if I am interpreting them correctly. He also mentions the habit of species in these two genera to hold their second pair of legs aloft to give the illusion of them being antennae, which we noted for this individual and can attest to its effectiveness!
For more about ant mimics that I have found in Missouri, see my previous posts Flower ants? Check again! and North America’s itsiest bitsiest longhorned beetle.
Cutler, B. 1988. A revision of the American species of the antlike jumping spider genus Synageles (Araneae, Salticidae). Journal of Arachnology 15(3) :321–348 [pdf].
© Ted C. MacRae 2018