The 44th Edition of the Circus of the Spineless is up at Marmorkrebs.blogspot.com. The Circus of the Spineless is a monthly blog carnival devoted to all things invertebrate, including ants. It was started in 2005. If you are interested in finding out more, visit the Circus of the Spineless home page. Next month’s carnival will be at Greg Laden’s Blog.
While investigating the Dorymyrmex bicolor ants I posted about on Monday, I spotted a few other ants that looked similar, mostly because of their red-brown and black coloration.
On closer observation, however, these ants were obviously another species. First of all, they were almost double the size.
The long hairs on the underside of their heads gave it away that these were harvester ants in the genus Pogonomyrmex. The ‘beard” of hairs, called a psammophore, is characteristic of the genus. In fact, the name Pogonomymrex means “bearded one.” Psammo comes from the word for sand in Greek, so the psammophore acts like a basket or an extra pair of hands to help the ants move sand, dirt, and probably some types of food as well.
These turned out to be a color variant of Pogonomyrmex californicus. Cole (1968) describes the species as concolorous light ferrugineous red in coastal California, moving to concolorous black or brown to the eastern part of its range in southern Texas.
Ants of the Southwest has a good page about these harvester ants that shows some of the the color variations.
It seems that Dorymyrmex bicolor and Pogonomyrmex californicus are often found in the same open, arid environments. It’s interesting that at this Maricopa, AZ site their coloration is so similar.
We’ve been seeing a lot of ant lion pits lately.
The insect at the bottom of those funnel-shaped pits is the larval stage of the ant lion, also called a doodlebug. Ant lions are found in warm areas throughout the world, including Florida and the southwestern United States.
The ant lion larva looks a bit like a lacewing larva, and the two are related. Here’s a photo of an ant lion larva from Iowa State University. Some species have even longer jaws.
The ant lion larva digs a pit in loose dirt or sand near ant colonies. We’ve had a particularly dry year and there is a lot of powdery dry soil, which the ant lions seem to prefer for constructing their pits.
When an ant or other small insect falls into the pit, the larva flicks sand or soil at it to knock it towards the bottom. Once the ant is within reach, the larva grabs it and drags it under the sand to eat it.
When the larva attains its full size, it pupates. The pupa is round and covered with a layer of silk. The adult ant lion emerges from the soil. It is slender with wings with many veins that fold back over its body when it is at rest. The adult might be mistaken for a damselfly or dragonfly. Firefly Forest has a fantastic photograph of an adult ant lion.
Edit: and now I have my own photographs of adults.
This little ant is fairly easy to identify.
First, look for the volcano-cone-shaped nest.
If you spot some active ants with reddish-brown heads and alitrunks, and black gasters, take a closer look.
If there’s a cone-shaped bump on the posterior dorsal surface of the alitrunk, then you’ve found Dorymyrmex bicolor.
Dale Ward has some close-up photos to show the characteristics of this species.
We saw it in typical habitat, which is open and dry. In this case the were at an agricultural research station in Maricopa, Arizona.
Dorymyrmex commonly feed on nectar and honeydew. Check out the nearby guayule flowers.
Guayule is a plant grown for its latex, which is used as a natural rubber.
Obviously, insects find it useful too.
