We all know how ants forage for food. A bunch of workers are sent out randomly, then, upon finding some delicious munchie, each worker lays a chemical trail back to her nest in the hopes that other workers will follow suit. Whether or not nest mates do in fact reinforce a given trail is dictated largely by an emergent, semi-random selection process involving factors like the evaporation rate of trail pheromones, distance of a food source from the nest, and the size of the food source. So, that’s how all ants forage for food. Except it’s NOT!

The reproductive system of most ants is pretty freaky, by human standards. Unlike in our species, where all individuals have a diploid set of chromosomes, nearly all ant species utilize a “haplodiploid” system in which females are diploid and males are haploid, with only one chromosome for each chromosomal site. So, in order to produce males, a queen lays unfertilized eggs, while in order to produce females, the eggs must be fertilized.

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A pleasing chromosome. Photo: Source

Polydomy. It’s a thing. It’s a thing where a single ant colony occupies completely separate nesting chambers rather than a single nest site. Polydomy, in creating a more distributed nest structure, has been theorized to increase foraging efficiency and enhance acquisition of a more diverse set of resources. Yet, despite the prevalence of hypotheses and theoretical work relating to polydomy, little work to date has experimentally tested the impact of polydomy on foraging efficiency.

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Temnothorax ants in their acorn home. Photo: Alex Wild

Have you ever been stung by a fire ant? Even if you haven’t, you probably know how (supposedly) bad and evil fire ants are. Yet fire ants, and a couple other well-known invasive ant species like Argentine ants, are only a few out of about 13,000 known species of ants, and they give all of these other species a bad rap. So today, let’s look at a new study by co-first authors Kevin Li and Yifan He and colleagues that properly flips the script: invasive plants push around friendly native ants.

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The big bad shrub, Elaeagnus umbellata