Houdini Insects: How to Prevent Escaped Ants

If you have ever had a run in with pests, then you likely know just how difficult it is to keep unwanted species, particularly ants, out of our homes. Often enough sealing doorways and putting food away is not enough to get rid of some of the more tenacious species, which merely find new ways inside where they can continue to cause damage and annoyance. The ongoing quest to remove invasive Argentine ants from the Channel Islands highlights just how difficult removing such pests can be. While studying ants in labs may seem like a very different problem, after all it involves keeping colonies alive rather than trying to exterminate them, there seems to be a significant overlap between the difficulty of trying to keep pest ants out of unwanted spaces and trying to prevent laboratory ants from escaping.  

Recording the movement of turtle ants in the lab also gives the ants many different escape routes

While often the study of any animal requires keeping whatever is being studied contained within the lab, this task is particularly challenging with turtle ants. Turtle ants, unlike Argentine ants or many other species that might be kept in a lab, are arboreal, and are thus highly adapted to climbing. As such, when dealing with turtle ants in our lab, one of the universal rules is that if something is climbable, ants will find a way to climb it and escape. Recently in bee lab we have been using RFID technology to track and scan individual ants, which has stressed the limits of this rule. In order to properly scan tagged ants, ants must pass extremely close to an RFID scanner at just the right angle. However, placing such scanners near ants creates a lot of problems: if the scanners are not close enough the tags will not scan and if they are too close the ants will climb up on them and escape into the lab. In addition, ants will rarely choose to pass under a scanner and instead will find any other way to bypass it. As such, using such technology requires designing ways to get ants to travel precisely under the scanner without climbing it or getting stuck to anything.

For experiments on the ISS escaping ants would be very bad news. While escaped ants in bee lab are less of a hazard, it can still be a lot of work to keep them contained

Our solution was to create nest caps, plastic covers that go over top of our turtle ant nests and force them to travel underneath the RFID scanner before entering or exiting a nest. I solved this design challenge with the use of laser cutter, which allowed us to precisely cut plastic pieces that could fit over top of the very small glass tubes the ants nest in. While these nest caps allowed us to scan any ant that travels in or out of a nest, it initially did not solve the issue of keeping ants in the experiment arena. For that task, most of the pieces of the nest cap and the rest of the arena that houses the ants must be coated with fluon, a substance that prevents ants from climbing on the surface. Unfortunately, fluon is a tricky substance to work with; touching any fluoned surface often removes part of the thin, slippery layer it creates, rendering it useless for keeping ants contained. Even careful fluoning has not prevented some most athletic ants from climbing on the RFID scanner, so we wrapped plastic coated in fluon around the RFID scanners themselves. While each of these steps has improved our ability to keep ants contained and properly scanned, it does add increasing complexity to setting up experiments.

Our setup with a nest cap and attached RFID scanner

While these last experiments have certainly been useful in revealing just how successful turtle ants are escaping, it's difficult to apply this knowledge to keeping unwanted ants out of our homes. For most people brushing fluon along the outside of your house or on the legs of furniture is probably not worth the reward of keeping out a few ants (not to mention the practicality of getting that much fluon). Yet, it does confirm that whether we are trying to keep ants outside of our homes or inside our lab requires coming up with novel ways to contain or redirect these incredibly resourceful insects.

Despite our best efforts at fluoning, an ant still manages to climb partially up a box

Media Credits

[1] Photo by Professor Donaldson

[2] Video by NASA Johnson Space Center https://youtu.be/hfJ5SI0ee-M?t=231

[3] Photo by Michelle Lilly

[4] Photo by Professor Donaldson