 large repletes can be found in mature honey ant colonies, each patiently hanging and waiting to serve up dinner when called upon by its nestmates.
Argentine Ant. Linepithema humile.
Argentine Ant tending soft scale for honeydew. Image courtesy Penarc.
Identification. The Argentine ant is a one node, small, shiny, brown ant with only one size of worker. Workers are usually about 1/12 to 1/8 inch long. The queen ants are much larger, sometimes reaching 1/4 inch in length. They nest outdoors under logs, concrete slabs, debris and mulch. Argentine ants build very large colonies and can move rapidly. During winter months, this ant will move indoors.
Biology. This ant is successful and hard to control because:
· Different Argentine ant colonies in a same general locale are not enemies. Even the many queens in a single colony or separate colonies are friendly to each other.
· Argentine ants are not too "picky" when choosing a suitable site to infest or colonize. They readily (as you will read about in move their nests during the changing seasons and other conditions.
· These pests are omnivorous; they seem to never be in short supply of food.
· Each colony of Argentine ants contains a multitude of workers.
· Each worker is more courageous and harder worker than most ants. Creatures that attempt to prey on Argentine ants are confronted with an army of stubborn bugs that never runs from a fight!
· The queens of most ant species are usually egg-laying machines. The queen ant of Argentines actually helps in the care, grooming and feeding of her young.
· Most species of ants mate and reproduce by swarming; the Argentine mates in the colony, unexposed to the perils of birds, frogs, lizards, predator insects and extreme weather conditions. A swarmer reproductive (as seen with fireants and carpenter ants) has about 1 chance in 1,000 of surviving and successfully reproducing. The Argentine ant queen always succeeds!
Distribution. Originating from Northern Argentina near the Paraná River and surrounding regions, the Argentine ant now occurs in most regions with Mediterranean climates or with mild winters and moderate to high humidity. Argentine ants are established in at least 15 countries on six continents and many oceanic islands, including New Zealand, Japan, and Hawaii. The global distribution of Argentine ants continues to expand. Humans have been the primary factor in their spread, however, this ant can also disperse into new areas without human influence. The Argentine ant is widely distributed in California, with highest abundance in coastal areas, along rivers, and in urban settings.
It was discovered by scientists two years ago that native Argentine ant (in Argentina)colonies living in close proximity were territorial and aggressive toward one another, literally tearing one another apart whenever they came into contact. The puzzling question to the researchers was, Why weren’t the introduced ants in California the same way? Why would an Argentine ant from San Diego dropped into a colony in San Francisco be welcomed, while an Argentine ant dropped into a colony two hundred meters away in its native country be torn apart?
In search to the answer to that question the genetic differences among the ants in Argentina were compared with those in various parts of California, from San Diego to Ukiah. Using some of the same DNA fingerprinting techniques employed by criminologists, it was discovered that the native Argentine ants were twice as diverse as the native California ants, explaining why the California ants regard individuals up and down the coast as close kin, while those different nearby colonies in Argentina do not. They have an innate ability to recognize other members of their colony based on how genetically similar they are to themselves. Basically the genes are similar among California ants because they are descended from a relatively small founding population In essence, the super colony that we see in California is in fact one big colony.
Damage. Because it does not sting or bite the Argentine ant is not a direct threat