Native Harvester ants

Harvester ants were abundant along the coast but have largely been displaced by the invasive Argentine ant. Pogonomyrmex subnitidus still occur in Torrey Pines State Park in San Diego along the coast. These ants collect seeds (hence the name) and the picture above left shows a nest. Scattered all about the nest are seed husks (right pic-nest hole in center) and abandoned refuse the ants carry from the interior to the surface. The pic below shows a pogo being attacked by another California native Dorymyrmex insanus (the small black ant). The pogo has a seed in its mandables and the dory is trying to steal it or is just raising hell. These ants primarily eat seeds yet apparently like most animals they appear to be opportunists. The following video shows a harvester ant attacking a moth larvae during a moth outbreak. During the spring of 2008, these moth larvae could be found everywhere crawling all over the ground and eating vegetation. This moth outbreak was followed by a carnivorous Carabid beetle outbreak refer ed to as a numerical response. The abundance of these caterpillars was a great source of food for many carnivorous insects.

Messor pergandei is another harvester ant found in the deserts. The following video is of a foraging trail in the Anzo Borrego Desert. At a certain point in time, the signal is given to launch a "seed run" (like a beer run..) along "trunk trails" where the ants pour out of the nest and head off in a column like an army on the move. They soon reached their destination and spread out -every ant for herself! With plunder in mandible, they soon return to the nest. It was striking to see this large column of onyx ants cross the trail that just 10 minutes earlier was quiet and abandoned.

Harvester ants lend themselves to a classic experiment. Optimal foraging theory predicts that an animal will maximize energy gain per unit time when foraging. You can test this easily. If you find a nest, you can place seeds (or oatmeal) of varying sizes at different intervals from the nest.

I was assaulted by a fly in the above clip.

Wikipedia : Messor is a myrmicine genus of ants with more than 100 species, all of which are harvester ants; the generic name comes from the Roman god of crops and harvest, Messor. The subterranean colonies tend to be found in open fields and near roadsides, openings are directly to the surface. The Vessomessor genus was recently added to messor adding 8 more species.
Colonies can achieve huge sizes and are notable for their intricately designed granaries in which seeds are stored in dry conditions, preventing germination. The structure of Messor spp. nests is complex and the genus on the whole is one of very accomplished architects.
Messor spp. are polymorphic and have a distinct caste of macrocephalic dinoergates [big headed workers] whose role is of carrying and cutting the large seeds which comprise much of the colonies' subsistence.
Equipped with a tough shining cuticle, Messor spp. are slow moving and form long, seed-carrying runs. Colonies tend to be monogynous and are founded by a single queen alone