What (Almost) Every Entomologist Wants for Christmas: A Fire Ant Pen

red fire ant
red fire ant

The red fire ant may have originally been found in the United States in the 1930’s. Since then, it has moved into several US states. This pest has invaded my property and wreaked havoc on my family more than once. My friend Sanford Porter is a researcher and an authority on red fire ants. I decided to try to make a fire ant pen for him. I asked Sanford to give me some background information on these ants before I began the fire ant pen project.

“The fire ant Solenopsis invicta is one of the world’s 100 worst invasive alien species. Fire ants are small reddish brown ants that range from about 1/8 to 1/4 inches in length. Fire ant workers build large earthen mounds which they use as solar collectors.  Workers move the brood up and down in the mound tracking warm temperatures that allow them to grow faster.  Florida pastures contain 20-50 mounds per acre and have an average of 1,500-3,000 fire ant workers per square yard.  Mature colonies can contain >250,000 workers which get very angry if someone steps on their nest.  Young children are especially susceptible to fire ants stings until they learn to recognize the mounds.  A fire ant sting typically hurts for a few minutes leaving a red mark which develops into a white pustule by the next day.  1-2% of people are allergic or sensitive to fire ants stings and they must always be alert for fire ants because they are virtually ubiquitous where ever people live in the southeastern United States.
As is the case for most exotic species, invasive fire ants were introduced without most of their natural enemies known to occur in their native South American range. As a consequence fire ant population densities in the USA are 5-10 times higher than those in South America. Currently, imported fire ants infest over 340 million acres in the USA and cost Americans an estimated 6 billion dollars annually for control and to repair damage to agriculture, households and other economic sectors. Fire ants are serious pests because they: 1) prefer human-modified habitats, 2) are aggressive stinging insects whose venom can cause allergic reactions in people, 3) have huge reproductive potential (like weeds), and 4) can negatively affect a number of native ants and other ground-dwelling animals. However, it is important to note that negative impacts on native ants are not universal and can vary with habitat and the presence of high density polygyne fire ant populations. In the last decade, S. invicta has emerged as a global pest, with new infestations established in Australia, Taiwan, mainland China, Mexico and many Caribbean Island countries.
Fire ants have many natural enemies in South America including pathogens, parasites and predators.  Phorid flies in the genus Pseudacteon are highly specific parasitoids of fire ant workers. They strongly affect fire ant foraging behavior. Maggots of these miniature flies develop in the heads of fire ant workers, decapitating their host upon pupation. Fire ant workers are keenly aware of the presence of phorid flies. A single fly usually stops or greatly inhibits the foraging efforts of hundreds of workers. Reduced foraging facilitates competition from ants that might otherwise be excluded from food sources in fire ant territories. The impacts of decapitating flies in South America is sufficient to have caused the evolution of a number of phorid-specific defense behaviors and these behaviors could only have evolved if Pseudacteon flies impact the production of sexuals. Other studies have shown that decapitating flies potentially vector pathogens and parasitize up to 5% of colony workers. Six species of decapitating flies have been established in the USA on red imported fire ants.”

fire ant decapitating fly
fire ant decapitating fly

Wikipedia reports:

“Red imported fire ants are extremely resilient, and have adapted to contend with both flooding and drought conditions. If the ants sense increased water levels in their nests, they come together and form a ball or raft that floats, with the workers on the outside and the queen inside. Once the ball hits a tree or other stationary object, the ants swarm onto it and wait for the water levels to recede. To contend with drought conditions, their nest structure includes a network of underground foraging tunnels that extends down to the water table. Also, although they do not hibernate during the winter, colonies can survive temperatures as low as 16 °F (−9 °C).”

In addition:

“The Food and Drug Administration (FDA) estimates more than US$5 billion are spent annually on medical treatment, damage, and control in RIFA-infested areas. Further, the ants cause about US$750 million in damage to agricultural assets, including veterinary bills and livestock loss, as well as crop loss.”

All this information (are you suffering from information overload yet?) spiked my interest in this pest. Fire ants have personally produced pustules on my body.

ant bite pustule
pustule from the bite of a red fire ant

When I asked my friend if he could get me some fire ants to cast into a pen for him, he quickly produced approximately 30,000 dead fire ants for me to experiment with. Don’t ask me how he knew there were 30,000 of the little buggers. I think he knows what a typical fire ant weighs and worked it out from there. He dried half the sample and dried and de-fatted the other sample. He thought the de-fatted ants might cast better in the acrylic. These ants are not very big, each 0.08-0.2 inches in size, so the bag of ants he had given me looked a lot like a bag of dirt!

I contacted Zac Higgins at NV Woodwerks to get some advice on how I might cast these into a pen blank. Zac seemed to think that I would have the most success gluing the ants to the brass pen tubes prior to casting. Seemed like a good approach.

I roughed up the two brass tubes in a slim line pen kit using sandpaper and then painted them with black lacquer paint. Then I coated the tubes with thick CA glue and rolled them through a pile of the dried, de-fatted fire ants. I applied additional coats of thin CA glue to try to stabilize the coating of fire ants. The two coated tubes were then installed in a silicone Resin-Saver mold for this type pen blank. Alumilite Parts A and B were weighed out in equal weights (or so I thought), mixed thoroughly and poured into the mold. BUT…I had not weighed out the parts accurately and had more A than B. This resulted in the mixture turning white. I went ahead and turned the blanks on the lathe, hoping that when I got down close to the ant layer all would be well. The resulting pen is shown below.

fire ant pen #1
first fire ant pen from Slimline kit

This shows the making of the pen, from our You-tube channel:

So I decided to try another method. This time I mixed the ants with the resin mix. Painted the brass tubes black and installed the painted tubes in the mold, then poured in the ant-resin mixture. This time the mix was correct and the resin cured as a clear acrylic. I temporarily forgot that these ants float! So that is what a bunch of them did. This resulted in pustules that were sheared off during the turning as you can see in the photo of the finished pen below.

fire ant pen #2
second fire ant pen from Roadster kit

Sanford was happy with both pens, but I want to try again. I will revisit the method of gluing the ants on the tubes with a proper resin mix. More on this later…. After Christmas!!

6 thoughts on “What (Almost) Every Entomologist Wants for Christmas: A Fire Ant Pen”

  1. Really cool, Skip! I lent my left foot to a bunch of fire ants to leave their signature pustuals on and learned not to kick fire ant hills. Duh I don’t doubt Sanford is very pleased with the outcome of these pens. Has Lois shown you the blob of amber I gave her with a tiny little prehistorical ant in it? I knew I would give it to her once I found it in the mass of stuff I brought from Maryland six years ago. Keep up with your super and Fun creations!

  2. This post makes it clear you are out of your mind, so I subscribed to your blog 😀. Oh, and I also subscribed because my husband and I are nerds who do both woodworking & quilting!

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