Tuesday, May 21, 2019

Picture-winged Fly

Delphinia picta loves Toyota trucks - REK
I have been seeing these small flies sitting on my pickup truck in the late evening.  I can't figure out why they are drawn to this surface although my wife suggests that they are attracted to dirt and grunge.  Ignoring her smarmy remark, I identified them as the common picture-winged fly, Delphinia pictaThe MDC Field Guide describes its head as having "...a remarkably large snout that makes the face look like an old-style gas mask."

  Reiner Jakubowski - CC
Love that petiole - John Lampkin
D. pictus is the lone member of the Delphinia genus.  It is found on rotting fruit and decaying vegetable matter, strengthening my wife's theory.  It is frequently confused with fruit flies but is not known to feed on any intact healthy fruit. 

The adults live up to 40 days.  They mate on the second day after emerging from the pupa, and presumably spend the following weeks in fond remembrance of their mating ritual as described in Wikipedia.  In the words of John Lampkin's photograph, "These flies suggest that it's worth a shot to try mating upside down wearing gas masks."
"The female will wave her wings gently and a male will respond by flicking his wings before copulation.  Courtship may also include one or more of the partners blowing a bubble from their mouth."
D. pictus - Lloyd Davidson CC
After that, life gets pretty mundane for D. pictus.  The female lays up to 500 eggs on decaying plant matter.  The larvae that hatch will go through 3 instars over 21 days before pupating.  I looked for a larval picture in the web in vain but in the search stumbled on a beautiful choreographed D. pictus dance routine on a beautyberry, Callicarpa americana, filmed by our own Master Naturalist videographer Linda Bower!  This Youtube video is a must see.
John Lampkin has Missouri roots, now a practicing "citizen naturalist" in Florida.
Linda Bower's fantastic videos are at Nature in Motion.

Editor's note:  Rewatch Linda's video and admire the beautyberry too. It's one of my favorite native shrubs.  You may yearn for one or more for your yard.