HMC Bee Lab: EVICTION NOTICE! Convincing Ants to Move Into Artificial Nests

[1] Disclaimer: this sign will not convince real ants to move

I have come to fancy myself an ant landlord, and let me tell you: evicting ants is no small feat. Ant colonies are a very stubborn group of ladies (and a couple gentlemen) that will defend their nests by barricading entrances with their heads, brush biting, and swarming your hands. So, why go to the effort of evicting ants if they clearly want to stay in their nests? To learn more about how they choose nests, we must motivate our Northern Caribbean Turtle Ants (Cephalotes varians) to move out of their hollow twig nests and into our artificial, translucent nests. These artificial ones can be easily opened, causing our ants to seek out new nests, allowing us to observe their nest choice in varying conditions.

Before I dive forward, let’s rewind to where these ants are from. Our turtle ants are collected in twigs in the Florida Keys where they make their nests in the abandoned beetle larvae tunnels of dead twigs in poisonwood trees. These holes are home to the entire colony, including the closely guarded queen and brood. When collecting ants for lab, we break off these twigs around a tree to collect the whole colony, and keep them in a container in the lab.

[2] A Busy Colony. We keep the ants in plastic bins with food resources, artificial nests (red cylinders on blue stands), and their original twigs from field collection. This photo exposes a mistake we made in which the red nests are too close to the wall, allowing ants to climb.

Unfortunately for the ants, we don’t want them in their twigs. Hollow twigs are safe homes because they are both difficult to see into and break. We, however, need to be able to see the ants and open up their nests to conduct nest choice experiments. We are investigating conditions like effects of location, quality, and competition on ant nest choice, so we also want our nests to be controlled in shape and size, and familiar to the ants. To accomplish this, we require the ants to live in easily manipulated artificial nests that can be opened, motivating ants to find new nests, and controlled for consistency. When we break the twig nests, they are no longer defensible, so the ants will choose a new nest (the artificial nest), taking any brood from the first nest with them. The artificial nest is precut lengthwise and taped together, so that during experimentation, the ants will again find their nest indefensible and seek out new nests. But recall… our ants are still in their twigs and we need them to move into our artificial nests. We solve this by cracking open the twigs with a knife, so the ants prefer the still-enclosed artificial nests.

Evicting the ants through twig cracking is a tedious process. First things first, we must choose a bin and open it up. This alone is a struggle if the ladies are climbers and have decided to scale the walls and lid of the bin. After brushing all of the ants back into their bin or a larger container (to provide more workspace), we can start. We remove all of the twigs from the bin and place them in the larger container. This immediately leads to an ant frenzy of exploring workers, my lab partner and I work as a team with one person moving twigs while the other wrangles ants back into the bin.

[3] Ant Wrangling. My lab partner brushes ants back into their bin using a paint brush. We do this whenever ants are possible to remove, so that limited ants are on the twig when the knife is present (we don’t want to chop them!).

To crack, we must first wedge a knife into the short end of a twig…

[4] Wedging. A knife is wedged into a poisonwood twig for leverage.

…and twist the knife, splitting the wood lengthwise …

[5] Twisting. We twist a knife in the twig until it separates into two pieces.

… until the twig snaps down the middle. Then again we are faced with an ant frenzy… but now they are scared and defensive! Be prepared for ants on your knife! Ants on your brush! Ants on your hands! Ants in your pants!? (just kidding… usually). It is time to brush, brush, brush the split twig until the ants are back in the bin. It is important to watch out for Her Majesty the Queen and her indispensable brood (the eggs, larvae, and pupae). This is a fragile and very important group. The brood is the future of the colony and the queen is the colony’s life line. If she dies, the colony dies. When we open twigs and find the queen or brood, we set the twig back into the bin gently, and the ants will gently move them in their own time.

[6] Brush, brush, brush! As ants try to evacuate the broken twig, they are brushed into their bin.

Once all twigs that are safe to crack have been cracked, we add some of our artificial nests to the bin, so the ants will move themselves, the queen, and the brood. Some twigs may need to be left in the bin if the queen or brood are not yet removed. We will check on those at a later day and crack them once evacuated. Once all twigs in a box are cleared and the colony moves into the artificial nests, we are able to experiment with that colony.

Last, but not least, we throw away the twigs without throwing away any straggling ants! Admittedly, some ants have been found in the trash can as we toss the twigs, but we do our very best to retrieve them all.

As I write this, we are still in the process of convincing all of our colonies to evacuate their twig nests for their new, shiny, cookie-cutter artificial nests. Landlording is hard work! Especially when your tenants – ten-ants ;) ?? – do not respect your eviction notice. One might even say they don’t appreciate that their new homes have only one wide entry and exit, and walls that are slippery and see-through (compared to their previous twigs with multiple escape routes, hiding places, and more easily climbed walls). Ungrateful if you ask me. Many ladies stubbornly remain in twigs, especially when they are guarding the queen or brood, but I have faith that we will be able to make all of their twigs inhabitable enough that they will take to their new nests.

HMC Bee Lab

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Tuesday, June 20, 2023

EVICTION NOTICE! Convincing Ants to Move Into Artificial Nests

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