Saturday, August 8, 2009

Bess Beetles

Today we made a trip to Tennessee for our family vacation. We are sitting at the Radisson Inn in Nashville, and plan to spend a few days here. We will probably visit the zoo, and the Grand Ole Opry. Tuesday we leave for Townsend, TN where we rented a cabin near the Smoky Mountains. I hope the insect activity at the cabin is good. I plan to take lots of pictures, and post some Tennessee Insects soon.

Tonight as the family watches some crazy comedy show on HBO, I decided to take the time to post about some very large beetles that I found in a hollow, rotting stump in our backyard. I literally tore that stump apart to see what was residing inside it. My husband said he wished he had the camera to get a picture of me. I apparently looked like a crazed woodpecker on crack as the wood flew in all directions in my quest to see what was residing in what was sure to prove to be the ultimate critter hotel. I was excited to find some very large beetles, called Bess Beetles.

This stump contained each life stage of this beetle.

1.) Bess Beetle Grub
2.) Bess Beetle Pupae
3.) Newly emerged Bess Beetle ( they are reddish in color when first hatched from the pupal cell, later turning black)
4.) Close-up of the face
5.) Fully matured adult

Bess Beetles (Odontotaenius disjunctus) are found from the Central United States and eastward. They go by many different common names including Peg Beetle, Betsy Beetle, Bess Bug, Patent Leather Beetle, and Horned Passalus. They grow quite large and with that horn on their face they can look very intimidating, but they are not known to bite. These beetles have a unique life cycle, the female will lay eggs within rotting stumps or other decaying wood. Both adults will care for the young larvae. They feed their offspring bits of chewed up wood. It takes up to one year for them to complete their life cycle to adulthood. It is not uncommon for the adults to consume injured larvae. Both adults and larva are capable of making squeaky noises through stridulation, by rubbing their abdomen against their wings. This is a form of communication between adults. If handled they will stridulate loudly. Look for them in or near deciduous woodland. Adults feed on decayed wood or fungus. Larvae feed on the chewed up bits of wood and fungus the adults give them. Both adults and larvae will also feed on their own fecal matter. This is done probably to insure they have the proper intestinal parasites that they need to digest cellulose from the wood fibers they consume. If you want to find these beetles look for a rotten stump or rotting logs and tear them apart, you are sure to find some as they are quite common. If not, well perhaps there will be something else even better.


  1. I have never heard anyone say, "I hope the insect activity at the cabin is good." while going on vacation. You certainly make insects fun. I had a visual image of you digging through the stump in your backyard. Good luck bug hunting in Tennessee. I have visited both Nashville as well as rented cabins in the Smoky Mountains. We loved them both.

  2. LOL, my husband and children think I lost my mind a long time, or at least it is permanently on vacation...I try to tell them I am source of entertainment for them, and who would they have to laugh at if not me. My daughter (age 16) does a great "eye roll" in my direction quite frequently.hehehe

  3. Great photos! Love the close up of the face.

  4. Thanks Moe, I love flies, their faces are just so fun!

  5. how do we know whether its male or female

  6. how can we get rid of it when they are in the house?

  7. MYC I am not sure that I have ever heard of these beetles being inside a house before. They are typically found in rotting logs and trees. I would make sure you have accurately ID'd them and that they are indeed this species. If they are, then you might look to see if there are any rotting timbers, logs, or other wood near your home. If there is, removing them should solve the problem. These beetles are harmless, and won't bite, or destroy your furnishings or structure. If you have rotting wood present on your home, that could be an issue although I can't say that for certain. Picking them up and placing them back outside should be sufficient in keeping them from returning.