On Friday, March 18th, 2022, I was on a walk with mom when I spotted a bright orange insect flying near me. I moved to catch it, but it hooked a sharp left turn, and I lost it, only to find it in the grass a few seconds later. I was then able to grab the insect, which was my first winter ant queen! I found another queen on that same walk, then caught one more on my trampoline.
On Saturday the 19th, on another walk with mom, I found two more winter ant queens. The first of these two is quite bizarre, as she is missing her left antenna for whatever reason, but I can only assume that she was attacked by workers from another ant colony, but she escaped from them. Aside from that, she is healthy.
Winter ants are quite peculiar ants whose scientific name is prenolepis imparis. They are commonly called winter ants because nuptial flights happen so early in the season that occasionally, there is still frost on the ground. To avoid competition over resources with other ants, colonies of winter ants only forage during cooler months, but not when it is snowing. During their foraging season, winter ant colonies will eat everything they can to build up fat reserves, which are stored in young and corpulent workers and possibly the queen. During the summer, the colony seals their own nest entrance and subsists solely off of the fat reserves in the very distended gasters of the corpulents. Unsurprisingly, many of the workers are fat-storing. The fat stores are also used to raise new generations of workers. Oddly, workers are only raised in warm months, presumably because that is when other ants are foraging and the winter ants thus can’t forage.
Queens lay eggs in batches so as not to deplete the fat stores of the colony too quickly. This effectively limits how quickly a colony grows, especially early on, when the colony is small. The nanitics are the slowest to develop, and subsequent generations take significantly less time to develop into adults.
The nest structure of these unconventional ants is fittingly perplexing. The nest has one entrance, and the main tunnel only has a few dead-end tunnels to offer workers temporary shelter from predators. Below 60 centimeters, however, the main tunnel suddenly has tons of tunnels and chambers branching off from it. The most likely reason for this design is to allow the ants to nest in moist clays and soils, as they have a medium-high humidity preference. They also nest down there because they like the cooler and more stable temperatures at those levels. Most of the fat-storing workers and the queens are found near the bottom of the nest, as the temperature is most stable down there, and that is also the part of the nest with the most protection. Winter ants are polygynous, meaning several egg-laying queens are tolerated within each colony. Queens are extremely friendly towards other queens of the same species, meaning that the chance of the queens killing one another is very slim. They actually have a much better chance of founding a colony when multiple queens are present, which is why I combined my queens into two test tubes. The three queens from Friday were placed in one nest, and the two from Saturday were placed in another nest.
Despite being quite obscure ants, winter ants play a major part in preventing the infamous Argentine ant, scientifically known as Linepithema humile, from spreading near where I live. The winter ants are able to avoid annihilation because they forage when the invasive ants are not likely to do the same, meaning easier access to resources. They are also aggressive toward other ants and produce secretions from their backsides, which are nearly always a winning weapon against Argentine ants and many other invasive ants. This combination of traits allows winter ants to thrive even though highly invasive enemies are right on their doorstep.
