Bledius flavipennis - Salt Panne Rove Beetle

Adult: 4-6mm.

Order Coleoptera/ Family Staphylinidae/ Subfamily Oxytelinae - Spiny-legged Rove Beetles

This little species is an inhabitant of salt pannes in coastal saltmarshes from Baja to Central California, and by their presence or absence, indicate the quality of the salt pannes and general health of the saltmarsh and tidal flushing. With their legs armed with tibial rakes, they burrow into the fine clay soils creating a very extensive system of tunnels and egg chambers just below the surface.

The beetles are often truly intertidal when high tides wash over their areas. This flushing is vital to their survival bringing a renewal of the microscopic interstitial diatoms (single-celled algae) which are its food, as well as lowering the salinity of the soil. The beetles take small chunks of mud with the large mandibles, macerating it with their specialized mouthparts, called maxillae. These are blade-like and edged with a series of bristles and hairs to filter out the diatoms which they swallow whole. The waste mud is then taken to the surface and cast around the burrow opening, creating what is termed a midden, which eventually covers the opening. It is these middens that reveal their presence and numbers.

Another animal of the lower tidal zone, which feeds on the diatoms is Uca crenulata, the fiddler crab - which also creates middens, or rather "chimneys" of emacerated mud about the top of its burrow, making an interesting case of convergent evolution of two unrelated species.

A number of other kinds of tiny beetles can be seen to regularly enter the tunnels of the rove beetles through the middens. These belong to the genera Tachys, 2.5mm, and Microlestes, 1.5mm., of Carabidae, predaceous ground beetles, and Anthicus and Ischyropalpus which average 2.5 - 4mm of Anthicidae, the ant-like flower beetles. These invade the home of the rove beetles to plunder the eggs of their host. The scientific name; Microlestes, literally means little robber. Bledius is greatly enlarged and not to scale with the others pictured.