Hentzia palmarum, adult male | Scott Co., Missouri

A brief break from photos from Argentina. Last week—just a few days after returning from my 8-week absence—I visited two of the sand prairie preserves in Missouri’s southeastern lowlands to try to photograph individuals from the unique, disjunct population the Festive Tiger Beetle (Cicindela scutellaris) found down there. Spring was well underway in the area, but several days of cold and rain seemed to have sent the tigers into their burrows until warmer temperatures returned. I spotted some Hibiscus lasiocarpus plants growing along the edge of a low wet spot adjacent to the prairie, so I started peering into their still unfurling leaves in hopes of finding the jewel beetle Paragrilus tenuis that utilizes the living stems of plants of this genus for larval development, but even they seemed to be awaiting balmier days. As I peered down into the leaves of one plant I notice a flick of movement, and carefully peeling apart the leaves revealed this adult male of the diminutive jumping spider Hentzia palmarum. Something was odd about this spider, and I finally realized the little guy was missing one of his characteristically enlarged and darkened front legs.

Note the elongated chelicerae.

Despite its missing leg, I became determined to photograph this spider. It certainly did not wish to be photographed, and perhaps that is the reason why. I gently snipped the leaf it was sitting on and held it in front of the camera, but every time I turned the leaf towards the camera it cowered and zipped around to the backside. Several times it attempted to flee by jumping off the leaf, but each time I pulled it back up by its thread before it hit the ground and lowered it back down onto the leaf again. Eventually I got a few shots I could live with. Of course, then I found this photo by Thomas Shahan (he describes it as “not a great photo…”) and almost felt embarrassed to show these here. Maybe I’d better stick to photographing tiger beetles!

The enlarged and conspicuously colored front legs of the males almost certainly serve some function in courtship. However, there seems to be no discussion of this in a recent revision of the genus (Richman 1989), and my further search for information about this only turned up one paper by Crocker & Skinner (1984). I really couldn’t understand anything the paper said, so for now I’m left with my presumptions that the legs are used as flags of sort—both to females to signal his availability and willingness as well as other males with more threatening intentions.

REFERENCES:

Crocker, R. L. & R. B. Skinner. 1984. Boolean model of the courtship and agonistic behavior of Hentzia palmarum (Araneae: Salticidae). The Florida Entomologist 67(1):97–106.

Richman, D. B. 1989. A revision of the genus Hentzia (Araneae: Salticidae). Journal of Arachnology 17:285–344.