Sciarid Snake

July 9, 2020

Here is a new  for me, Nick Christians.   I have never seen one that I know of.   It comes from Dr. Donald Lewis, depatment of entomology, here at Iowa State University and one of my former students, Damian Richardson, who is now owns his own lawn care company in Des Moines, IA.  Dr. Lewis tells me that this is very rare and he has never seen one in person, but that he has had occassional call on it over the years. 

Here is Dr. Lewis's report on the insident.

Damian Richardson gave permission to use his photos in a Turf Blog if you are interested in covering a “sciarid snake” which is not a snake at all, but rather at mass migration by hundreds or thousands of fungus gnat larvae.  Damian mentioned extra watering in this area as a contributing factor.

Here is my reply to Damian. 

I’m jealous that you have seen and photographed a “sciarid snake” and I haven’t.  Lucky you!  The sciarid snake is a mass migration of fungus gnat larvae.  It’s not uncommon to see them;  it’s just that I have never been in the right place at the right time.  I have seen photos but I have never seen one in person.  It must be amazing to see so many fungus gnat larvae moving en-masse.

Sciarids are fungus gnats, small harmless gnats that develop as larvae in damp, decaying organic matter.  A few fungus gnats are common in houseplants, and they often abound outdoors in damp areas such as wet soil, under grass clippings and mulch.  Essentially anywhere with continuous moisture and organic matter.

I don’t know what causes the migration of fungus gnat larvae or where they think they are going.  But hundreds of gnat larvae are moving in unison, gliding on a thin layer of mucous they secrete.  I believe it is a dispersal activity that allows a large number to move in relative safety by literally sticking together and conserving moisture.  These long, rope-like migrations are very temporary.  No control is needed.

Here is a link to more information about fungus gnats:

Note that near the bottom on the page, under Remarks, they state; "Sometimes abundant enough to form a crawling mass of several inches across and several feet long, similar to armyworm migrations."  That is what you photographed.

More photos:

Fungus gnat larvae are very, very common outdoors under mulch and leaf litter and other similar places that are constantly damp.  The fungus gnats are harmless and beneficial (they are recyclers of organic matter in the ecosystem). 




Donald Lewis

We always appreciate unusual things like this.  Feel free to send them too us any time.  Pictures are always a good addition.

Since I posted this, I received a video from Mark Storby, golf course superintendent in Wisconsin, of a Sciarid Snake on his golf green.  See video above, thanks Mark.