Wormlion (Vermilionidae)

Wormlion (Vermileonidae)

On a recent trip I stumbled onto pits in sandy soil. The first thing that came to mind was Antlions which congregate in dry soil. They sit in the bottom of the pits and wait for unsuspecting prey to fall in. Upon further investigation I found that there were small worm-like larvae in the bottom of these pits. They were somewhat strange looking having no pronounced prolegs or large sclerotinized mandibles to grab prey with.

Wormlion (Vermilionidae) congregation

So once I figured out that these were not Antlions I figured I’d throw in some prey to see what happened. When I did, I was surprised. The larvae grabbed onto the ant right away and sunk its mouthparts into it. After this display I decided to collect some of the larvae to rear them out and try to learn a little more about them. The first thing I did was take one to the office to try and identify what it was.

Ventral pseudopod located on the 5th segment. This structure helps the larva grasp prey with the help of the mouthparts.

Once under the stereo microscope I found a few key characteristics that helped get a positive ID on it. The first thing I noticed was a ventral pseudopod (image above) on its 5th segment. This structure assists the larvae in holding onto prey while it injects digestive fluids through its fang-like mandibles (image below). The second unique thing I saw was the shovel like posterior end containing 4 large protrusions. Each protrusion has long hair like structures to assist in anchoring the larvae for feeding (image below).

Here is a look at the mouthparts of a Wormlion (Vermileonidae)

Posterior end of the wormlion (Vermileonidae). This is the structure that allows the larva to get leverage when wrestling prey.

Top view of posterior end of the wormlion (Vermileonidae)

After I took some pictures with Mikes help, I forwarded them to Dr. Chris Tipping to see what he thought it was. With his response of possibly being a snipe fly I started doing some research. I found that this larva was in the Rhagionidae family historically but now has been placed in its own family Vermileonidae. The common name for this larva is “Wormlion” named after the Antlion (Myrmeleontidae). There are less than 80 species worldwide making this insect somewhat rare. The only distribution I found on this family in the US was in California and Nevada (image below). I think they are more widespread in other high desert-like or dry climates across the country. I am hoping to rear these out to see what the adults look like for a future blog.

Wormlion (Vermilionionidae) distribution

Written By: Rob Snyder

Rob Snyder has written 62 post in this blog.

I currently work out of the Butte County Cooperative Extension in Oroville, CA as a Crop Protection Agent. I received my B.S. in biology from Delaware Valley College, PA. There I attained a majority of my entomological knowledge from Dr. Chris Tipping and Dr. Robert Berthold. After graduation, I was an apiary inspector for 2 years at the Department of Agriculture in Pennsylvania. In my third year there, I still inspected some colonies but I mainly focused on The Pennsylvania Native Bee Survey (PANBS) where I pinned, labeled, entered data and identified native bees to genus species. Leo Donavall assisted me in learning the basics on positive Identifications of the native bees. Around the same time I began working on coordinating kit construction and distribution for the APHIS National Honey Bee Survey. I was also fortunate to conduct many of these surveys with fellow co-worker Mike Andree and Nathan Rice of USDA/ARS throughout California. All of these experiences have led me to where I am today, working to assist beekeepers in maintaining genetic diverse colonies resistant to parasites while reducing the use of chemical treatments in colonies. The BIP Diagnostic Lab at the University of MD is in an integral part of this process by generating reports in which we can track change and report to beekeepers vital information in a timely manner which may influence their treatment decisions.