Naturespeak A naturalist's view of the world

April 13, 2012

Ladies and Gentlemen…the Golden Dung Fly

Filed under: Uncategorized — wykes @ 10:53 am

My first introduction to the Golden Dung Fly was out on the windy Pointe Mouillee dikes.  Perhaps it goes without saying, but I was not seeking them (one can’t seek what one is ignorant of, one can only discover). I wandered slightly off the path to look at a dancing cloud of midges (something I was not ignorant of, but still not seeking). I crouched down and “discovered” that I was hovering over the dried carcass of a muskrat. The critter was little more than a flattened piece of rawhide with some feet and a tail sticking out. It didn’t smell due to the persistent easterly breeze and the fact that I was east of the dead ‘rat.

The skin was populated by a half-dozen large flies and they immediately grabbed my attention.  To heck with the dancing midges, I thought, these carcass flies were much more engaging. They were big, bold, and covered with a bright golden fleece. Dare I say it, but they were almost pretty (I’d say “cute” but that would probably trouble many of you beyond reason and cause you to abandon this post).  These yellow fellows were very active as well.

I spent a grand total of ten minutes observing these flies. Their activity consisted of jumping at, and over, each other like kids playing hopscotch. O.K., I realize that comparing children to carcass flies may seem a bit insensitive, but I suspect the flies probably wouldn’t take too much exception to that comparison. Never once did they feed on the carcass or enter into its oily crevasses – as small children would invariably do. The reason for this became obvious after I later researched them. In spite of their name, Golden Dung Flies don’t really eat dead stuff or even dung, for that matter. Dung flies feed on other flies that do eat dung and dead stuff!  Ladies and gentlemen allow me to introduce you to the Golden Dung Fly.

Now don’t get me wrong, now, these flies are all about dung and smelly things and every phase of their life revolves around it.  Their scientific name, Scathophaga stercoraria, pretty well sums this up. It means, through a combination of Latin and Greek words for dung, “poop loving poop beast.” It is like naming your child Poopy Crap McDung. It is recorded that these guys prefer the dung of horses and cows (or “pats” as they are euphemistically called). The adults feed on other flies visiting the pats, although they have also been known to ingest pollen from time to time.

One of the scientifically significant things about Golden Dung flies is that they have long been studied for their mating practices. The males and females gather at the smelly places, eat, and then mate with each other.  There is usually quite a bit of aggressive competition between males for mating rights. The study part involves a mechanism within the female which allows her to store the male sperm and selectively control the fertilization process. Sexy, eh?

Regardless of where she was impregnated, the female then lays her eggs in a choice fresh pile of pat. The larvae emerge and burrow through the waste seeking other insect larvae to feed upon. So, there you have it, even the kids don’t eat the waste- they just play in it. After 21 days, they pupate and later emerge as the golden hairy flies shown in these pictures.

I do believe that enough has been said regarding the Golden Dung Fly without beating a dead horse – or a dead muskrat. When next you encounter a putrid pat or carcass rare, seek the golden-fleeced fly and embrace it (mentally that is).


  1. I’ve never seen a golden dung fly; didn’t know they existed. I did discover a margined burying beetle on a dead shrew once. The lesson here is that it pays to look closely at dead things, I suppose…and, according to this post, at poop as well. (“It is like naming your child Poopy Crap McDung”–ha! Thanks for the laugh!)

    Comment by Patricia Lichen — April 21, 2012 @ 1:07 pm

  2. Thank you! Now I know what these flies are called. I was worried they were some new invasive critter as I don’t recall seeing them growing up.

    Comment by Barry — April 25, 2012 @ 1:27 am

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