EPOW - Ecology Picture of the Week

Explanation:   Only a centimeter long, this odd inhabitant of a small wetland in eastern Oregon is a larval stratiomyid, a soldier fly ... before it transforms into the winged, compound-eyed creature more commonly seen.   

Soldier flies are widespread.  Adults eat nectar but many larvae such as pictured here feed on algae in still water habitats.  Some larvae are indeed very aquatic; I removed this specimen from a small seep area to photograph it.  The photo to the right shows it in its native aquatic habitat. 

View a movie of this larva crawling outside of its usual aquatic environment (1MB mpg; or the same with music as a 1.7MB wmv; both files © Bruce G. Marcot).  Watch how it uses peristaltic waves of its body segments to move itself forward in a linear locomotion.

Are soldier flies useful to people?  In one experiment, black soldier flies were used to digest pig manure to reduce the waste bulk.   

Information:  My thanks to Ken Cummins and Peggy Wilzbach, aquatic entomologists, for the identification.  They also noted that it would be difficult to tell which instar this specimen is in (instars are immature growth phases).  Unlike mayflies which can have 20 or more instars, Dipterans such as the stratiomyid have only 3 or 4.  They are very tiny and don't stay long within the first instar.  This one appears to be nearly full size, so it might be in its 3rd instar.  Usually they can be identified to species only from the adult form.