Leaf-cutter ants. They aren’t from Washington even, but are an example of insect cultivation. They harvest leaves, to cultivate fungi, which they then eat. Pretty incredible! (Image: Brendan McGarry)
I had just cut down an old rotten stump when I noticed them. As soon as the round of wood spun off the bar of my chainsaw, hundreds of ants were running around in seeming panic. Some cast about, mandibles open, for the source of the disturbance. Others held little white larvae aloft, running in frantic circles. I felt bad I’d just bisected their colony, but that rotten stump had to go. That’s how people are with ants, we see them, we step on them, and then we move on with our big world.
Ants are members of the order Hymenoptera, along with bees, wasps, and sawflies. This puts them up there with Coleoptera (beetles), Diptera (flies), Lepidoptera (butterflies and moths), as four of the most speciose orders of animals in the world; there’s at least 150,000 hymenopterans. They have fascinating social systems, exist on every continent except for Antarctica and scientists estimate that they make up 15-20% of the world’s terrestrial biomass. Some species create massive underground colonies and others that weave together leaves for a home. Some cultivate fungi for food and others travel long distances to bring back all manner of food. You get it, they’re diverse.
When the movie “Antz” came out, I couldn’t help but cringe, and not just because of the “z.” I was being nitpicky, but I was bothered by the fact that they transposed human concepts of gender and sociality onto ants without a backward glance. Ants are eusocial, which is an organization of animal sociality that has cooperative brood care, overlapping generations, and divisions of labor with reproductive and non-reproductive castes. In a very generalized, simplistic ant colony, there’s a fertile queen, a few mating males, and lots of sterile, female workers (which in some cases are divided further by morphology into various roles, like “soldiers”). Queens can lay fertilized eggs (with semen saved from an encounter with a male), which mostly become sterile workers, or lay unfertilized eggs which become reproductive males (called drones). Colonies of ants are mostly made up of sisters. The few dumb brothers’ only task is to fly off and mate with a queen and then die. Dreamworks was so wrong, specifically by having male characters in the movie doing anything but breeding, but I’m probably one in a million who really cared.
Ants can be troublesome. Because they often have many mouths to feed, they have large appetites, and their numbers mean that it’s very difficult to get rid of them. Lucky for us, we don’t have terrible stinging fire ants (genus Solenopsis), and have avoided biodiversity decreasing Argentine ants (Linepithema humile). We call tiny black, non-stinging ants in our home “sugar ants,” because they are attracted to sweet things, but this is a colloquialism for several species of food-raiding pests (most of which are non-native and thankfully aren’t as bad as species in hotter clines). Notably large Carpenter ants (genus Camponotus) should really be called sawyer ants, because they excavate wood (sometimes to disastrous results in our homes) to expand their colony, leaving a calling card of sawdust. And, while I think nuptial flights are a natural wonder, because those involved are reproductive males and females going off to mate and create new colonies, having hundreds or even thousands of flying ants converging on your backyard is hardly pleasant.
Ants photographed near the Hill, collecting pollen and nectar. (Image:: Brendan McGarry)
I wish I could just list a few common species here to learn and identify, but without a good microscope and a technical key, you won’t get far, even if color and size help. Equally so, despite a relatively low diversity in our state (around 84 species), there’s infiltrators on the Hill from foreign lands, which complicates things. You can still glean information from ant behavior and ecology to get your closer. Easy to spot in our Western forests (but uncommon on the Hill) are thatching ants of the genus Formica, because they build huge mounds of pine needles and other organic material to house their colonies. We call pavement ants (Tetramorium spp.) this because of their habit of excavating under concrete slabs (you’ve undoubtedly seen them all over). We see more ants now because it’s warm. Winter is coming, and then they’ll retreat underground where the temperature is consistent.
Despite untold ecosystem services as pest controls and detritivores (eating dead stuff), there isn’t a lot of popular information about ant identification. Mostly it’s focused on how to recognize a few pest species out of the many beneficial or harmless species, (here’s a great page sans volatile rhetoric from my alma mater). To broadly portray a diverse group of over 100,000 species primarily as pests is quite the display of human chauvinism. Just look at this and tell me they don’t deserve more from us?
As always, I cannot tell you all there is about ants but I do hope to come back around to this subject again. There’s a lot of caveats to ant ecology, as they’ve been around for some odd 90 million years. So, in the meantime, what I want from you, is to take a second to think about these tiny wonders before they fall under your heel (or you cut down their home).
