An odd projection sticks out from a mossy log or a corrugated pattern seems suspicious in its irregularity— spotting cryptic arthropods is always an exhilarating experience in the neotropics. Often, I wonder what exactly my brain picked up upon to peer a bit closer, or if it was simply due to random chance. The lichenous animal that lay before me on this occasion, though, was out of its element, laying still on a patch of brown leaves at the base of a terciopelo tree (Sloanea terniflora). In a rush of excitement, having only seen a small green nymph of this species before, I immediately grasped the insect. It was an illusory phasmid (Trychopeplus laciniatus), an arthropod that very few others rival in extravagance. As a friend once told me, this stick insect is like the terrestrial equivalent of a sea dragon, with so many ornamental elaborations that its body plan is difficult to understand at first glance. Almost every segment of the body is warped or contorted, and even the antennae are wavy, ending in an abrupt squiggle. Triangular structures on the legs resemble a thorny stem, flaky pronged extensions mimic liverworts, and spiked rosettes on the thorax are as if it was adorned with tiny sea urchins.
After picking the phasmid up, it swayed back and forth emphatically to obscure its features, vibrating strongly with every movement I made. At the time, I was too absorbed by this enigmatic finding to ponder about its behavior, and it wasn’t until I reminisced at night that I realized I may have caught it at an inopportune time. Although the habits of Trychopeplus in nature are largely unknown, the genus is thought to exclusively dwell among mosses and lichen. It’s possible that the phasmid made its way down from the upper strata to lay its eggs under leaves on the ground. Like the insects themselves, the eggs of Trychopeplus are very intricate. A polygonal mesh surrounds the embryo and external seed-like fringes evert when exposed to humidity, which may serve for protection and maybe even dispersal. I kicked myself a little bit for not searching for the eggs to make further observations and learn about their early development. The following day I made my way back to the terciopelo tree, but the phasmid was long gone, and no evidence of the ova could be found.
Photographed after capture