Wednesday, November 6, 2019

Yellowjacket Nest

Syrphid fly, Milesia virginiensis on my arm

I was chasing a tiny skink through the leaf litter six feet from our front door when I saw several yellow flying insects.  We have Syrphid or flower flies on our deck regularly, scaring visitors as they look like yellowjacket wasps but I wasn't fooled..... yet.  I got out my pocket camera to get some closeup videos, a big mistake.  Just then I saw five swarming around in the grass and then more hovering around a finger sized hole.  I thought "Do Syrphid flies nest communally?"  just 2 seconds before the first of several stings - "Yellowjackets!"

I ran backward swatting them off and the attack stopped as the swelling started under three stings.  We love nature but occasionally nature gets too close and our house qualifies as unnatural.  After applying ice to the stings with unimpressive results, I got a can of "kills on contact" wasp spray and soaked the hole from a distance several times.  I returned 20 minutes later with my telephoto camera. (Note to self - video wasp nest = telephoto).

In spite of the insecticide, the hole was busy with wasps coming and going for the next 8 hours.  Many of the outward bound were carrying something in their mouths.  They were moving too fast to see what they were carrying.  It looked like they were panicked and evacuating the hole.  So much for the "kills on contact" on the spray can.  Apparently Ozark yellowjackets can't read.

YJ with a mouth full of rock - REK
After converting the video to 8x slower playback* it became obvious that they were not planning on leaving.  They were actually carrying out small pebbles, enlarging their quarters, carrying on like nothing had happened.  I had a lot to learn about yellowjackets.  This intriguing Youtube video by Bret Davis, aka Hornet King** was a great introduction to the subterranean world of yellowjackets.

Outer bottom layer with side holes - B. Davis
YJ usually build their paper nests underground, starting in a small hole created by a mouse or something similar.  As they create the cells for the offspring of their queen, they work around the outside edges of the paper nest, excavating rocks and soil to enlarge the nest.  As the colony grows they create several side holes (starting at 20:30), slowly digging a larger hole which will be filled with new layers of the nest.

Seven layer yellowjacket nest -  Hornet King, B. Davis
So how big do they get?  This one was removed from a 14" X 9" hole fully excavated by the wasps themselves!  I don't know about records but Bret's weighed an estimated 10 pounds.  (Taking a nest with scattered yellowjackets on it to the bathroom scale in the name of science probably isn't a good idea.)  His nest was seven layers deep.

Weaving a cap -Click to enlarge  (HK)
His video is 27 minutes long but well worth the time.  Unlike many videos focusing on the excitement and danger of stings, Hornet King vividly shows the process of nest building.  Here for instance he shows the larvae beginning to weave a silk cap to to paper homes where they will pupate.

As I nursed the swelling over the next 5 days, I identified my new neighbors as eastern yellowjackets, Vespula maculifrons.  Baldfaced hornets (Dolichovespula Maculata) are yellowjackets with a pale makeup.  Both are colonial nesters but hornets nest above ground while YJ are usually below ground or in enclosed spaces like the soffit of a house.  We have that problem with our red Polistes wasps, but at least they aren't quite as irritable.

Additional thoughts from Hornet King:
There are many subspecies of wasps in the Dolichovespula grouping. Another of the Aerial nest builders is the Dolichovespula Arenaria, which look very similar to the subterranean YJ (Southern Yellow Jacket - Vespula Squamosa) species. This subject is always a area of confusion for my many of my viewers as they think "Yellow Jacket" is a term only given to yellow and black wasps. However, there is more to the classification than just its yellow body (Bald faced hornet being a prime example)

 Promachus hinei with YJ

I did have some slight consolation as I sat on the porch swing balancing ice on my stings.  A loud and coarse buzz announced the arrival of a robber fly, Promachus hinei, on the swing chain.  It was holding a yellowjacket in its jaws and seemed to be showing off its catch.  I photographed it and watched it fly away.  It pierces the body of its victim and sucks out the insides, appropriate justice in this case.

Slow motion video of yellowjackets rock excavation
**  The Hornet King Youtube channel has many more detailed explanations of the nests of other colonial nest builder wasp species.
Yellowjackets on Bugguide.
Yellowjackets and Hornets on University of