In a previous post, I lamented the fact that I had never actually seen a live antlion larva, or doodlebug (family Myrmeleontidae). Lovers of sand, I’ve seen their famous pitfall traps many times, especially in recent years as I’ve searched sand habitats for my beloved tiger beetles. Occasionally, I’ve stopped to jab my knife under a pit, give it a quick flip, and search the freshly turned sand for the maker of the pit – never seeing anything. It never bothered me much either – there were always beetles to catch! Two weeks ago I returned to the sand prairies of southeastern Missouri to look for additional sites for Cicindela scutellaris (festive tiger beetle), and as we searched one particular site on the Sikeston Sand Ridge I once again saw the characteristic funnel-shaped pits amongst sparse vegetation in the sandy soil. I decided this time I needed to give it a good effort – how can any self-respecting entomologist accept not having ever seen a live doodlebug? As I’d done many times before, I kneeled down, gently put the tip of the knife about an inch away from the edge of the pit, and then jabbed its full length assertively into the sand and under the burrow and flipped it over. Like previous times, I studied the turned sand and saw nothing. I stirred the sand gently with the tip of the knife and studied it again – nothing. I tried another burrow – again, nothing. I decided right then and there that I was doing something wrong – I could not simply be picking ’empty’ pits. I continued staring at the turned sand, and then I saw movement – I looked closer, and it seemed as though the sand itself was moving. At last I made out its outline – I had finally succeeded in finding a doodlebug! I dug up another burrow, and knowing what I was looking for this time I had no problem quickly locating the little creature. I watched it as it lay motionless – perfectly camouflaged by its color and with sand grains sticking to its body, and chuckled as it buried itself almost instantly with a quick, backwards shuffle into the sand. Who knows how many doodlebugs I’d successfully dug up in the past, completely overlooking them as they lay disguised and motionless in the sand.
More than 100 species of antlions, representing at least 19 genera, live in the Nearctic Region, although much of this diversity occurs in the southwestern U.S. and Mexico. Despite the commonly drawn association between antlions and pitfall traps, in North America only those in the genus Myrmeleon actually exhibit this behavior. This larva dug a pit and so must represent a species of Myrmeleon – perhaps M. immaculatus, a common species in North America and one whose adult I observed last fall on a nearby sand prairie remnant. Species in other genera have free-living larvae that hide under objects or roam underneath the sand, from where emerge briefly to hunt for prey.
For those interested in learning more about antlions, Mark Swanson has an excellent website called The Antlion Pit.
Copyright © Ted C. MacRae 2009