Forelius pruinosus

School of Ants collection
Literature record

Forelius pruinosus


From Dr. Eleanor's Book of Common Ants

A.K.A. : Forelius

Size: 0.07-0.1 inch

Where it lives: Masters of climate, Forelius can nest just as happily in your kitchen cabinet as they can in the middle of the desert. They prefer grassy or open ground and often nest under rocks.

What it eats: Excellent scavengers, Forelius will eat meaty foods like dead insects and animals, but they often prefer liquid sweet treats, like those produced by aphids.

What’s the big deal?

The first time I ran into a Forelius pruinosus worker I’ll admit I was underwhelmed. I was ant hunting in a grassy park, laying bait to see which ant species lived in this anty jungle. I’d brought along the perfect enticement: tuna fish mixed with honey. I measured out this ant catnip onto an index card in a tiny spoonful, which I placed on a spot of bare ground under an oak tree. Then I lay in wait to see who would show up.

Before long, many of my old friends came nosing around. A rusty red field ant with speedy long legs was the first to arrive at the party, bending down, legs spread wide like a horse, to drink in the buffet. She was followed by a small flock of odorous house ants, who were chased away by a steady throng of shiny little black ants. A few acrobat ants briefly lurked around the index card’s borders, considering the feast and returning to their tree, evidently thinking better of it.

As the little black ants began to scatter, a collection of tentative ant workers I didn’t recognize loitered in a tidy line on the sidelines. Plain-Jane, brownish-red and about half the size of an apple seed, these ladies were otherwise unremarkable in appearance. Unlike the frantic field ants or the spirited little black ants, they were a bit boring.

Watching these austere, drab ladies as they efficiently carried off the remaining bits of index card bounty, I almost felt sorry for them. Where are the great spines of winnow ants? The gargantuan size of wood ants? The giant noodles of big-headed ants? The happy, heart-shaped bottoms of acrobat ants? Unembellished at best, Forelius pruinosus, very common ants with no common name (Klotz and Hansen 2008; Whitford 1999), don’t make a knockout first impression.

As I became better acquainted with them, I learned there’s more to Forelius (it’s fun to say: four-eel-ee-yus) than meets the eye. So, in salute to the lesser known (and maybe less appreciated) Forelius ant, I give to you a countdown of what I believe to be her top five, most notable attributes:

Five. Forelius are masters of climate. They love to nest in open areas and are able to survive just as well in temperate fields and your kitchen or bathroom (Field et al. 2007) as they can in deserts (Rojas and Fragoso 2000; antweb.org).

Four. They smell good. Like odorous house ants, Forelius have a pleasant aroma when you smash them. Their bottoms are packed with a chemical that smells sweet, almost like something you’d use to clean your counters (Blum et al. 1963). But don’t be fooled by their bouquet bottoms: This smell-good chemical is actually an alarm pheromone that attracts their nestmates, who then form a mob to help their sister in danger (Scheffrahn et al. 1984; Blum et al. 1966).

Three. These clever ants have an entrepreneurial spirit. They figured out a way to trade their bodyguard skills, whether they’re looking out for other insects or for plants, for their favorite syrupy treats. Take the catalpa tree, which gets the most out of this ant’s fondness for dessert. When catalpa trees put out their leaves, hungry little Jabba the Huts called catalpa caterpillars come to gobble them up. If nobody protects the tree from these fat piggies, catalpa caterpillars can eat every last leaf off the tree, hurting the tree’s ability to produce food to survive. To save themselves from starvation, catalpa trees call our Forelius ants. As soon as a caterpillar chomps down on a catalpa leaf, the tree oozes nectar along its branches, which attracts Forelius ants. The ants don’t want anybody messing with their sugar stash, which means the unsuspecting caterpillars are out of luck (Ness 2003). Other plants, like wild cotton plants, similarly benefit from Forelius’ fierce love of sugar (Rudgers et al. 2003).

But Forelius have no special loyalty to plants. When caterpillars offer to pay them in sugary treats, Forelius are quick take the job. Sometimes, they visit and protect the endangered Miami blue butterfly caterpillars, who offer them a sweet reward for their efforts (Saarinen and Daniels 2006).

Two. They have the absolute worst party etiquette. To keep other diners off the buffet, Forelius go to those ants’ nest entrances in large numbers. Instead of dropping off an invite, they spray bug repellent on the nest entrance, driving the nest’s inhabitants deep down. Then, they block up the entrances so those other ants can’t escape (Holldobler 1981). Voila! All-you-can-eat is ready and waiting just for Forelius.

One. Forelius can dance! Whenever these ladies are faced with conflict or danger, they try to appease each other with a little jig. They shake their bodies around like they’re doing the jitterbug and then point their bottoms in each other’s faces (Holldobler 1982). While these dance moves might not make us the belles of our balls, they save Forelius from a lot of cuts and bruises.

So what if they don’t have giant spines or huge heads? So what if they don’t have cool-shaped bodies? As it turns out, while Forelius ants may look polite and buttoned-up, they’re anything but run-of-the-mill workers. With their sweets-loving, booty-shaking, party-crashing ways, Forelius are a great reminder that we should never judge an ant at first glance.

Find out more about this species at Antweb and see more photos by Alex Wild.