Western Harvester Ants are pretty common here in Southwestern Colorado. They are part of the landscape – you can often see their nest mounds from the highway as you drive through the high desert.
And if you watch the mounds after a rain in the Summertime, you may see the spectacle of a mating flight.
After a Summer rain, you may see the workers and winged (sexual) ants pouring out of the nests. The area around the nest seethes with ants. The nest’s young queens and males are almost defenseless on their own, and the workers try to clear the area around the nest of threats.
The young queens are beautiful. They look like the workers in many ways, but are larger, and with wings. The queens have a big, humped thorax to contain their flight muscles.
Males, on the other hand, are flimsy affairs. They are essentially flying packets of sperm and sensory equipment. They won’t live long after they mate.
One thing that puzzles me is the number of hairs around the base of the male’s legs (see the photos below). Hairs in insects are often sensory – a way to get information about the outside world through the suit of armour that is the ant’s exoskeleton.
Presumably all of these long sensory hairs help the male with mating – either the actual act of mating, or in wrestling with other males when competing to mate.
The winged males and females fly away from the nest and land in mating congregation areas. These areas are usually open, clear of vegetation. On the day I took these photos, the ants had chosen a parking lot.
The parking lot was roughly a ten meter square, and was covered with clusters of mating ants. Each cluster of mating ants is a female ant and a group of males attempting to mate with her. The males try to mate with as many females as they can, and the competition for females is fierce.
The females will typically mate with more than one male. This is the only time they’ll mate, and they need to store enough sperm to enable the queens to produce worker ants for many years.
After mating, the females would try to find a clear spot in the mating area. If another male ran into her, he’d try to wrestle her into mating again.
The females would usually groom for a bit, then fly off.
She’ll fly until she finds an area where she wants to nest. Then she’ll land, break off her wings, and try find a good spot to dig a nest hole.
It’s very difficult not to feel sorry for the queens at this point. She is almost entirely defenseless, and her chances of surviving long enough to get a nest going are not high.
