Argentine ants captures the world - or at least areas with temperate climates.
They have colonized the coastal areas of the Mediterranean, and seized parts of South Africa, Hawaii, California and Australia.
Uninvited guests a devastating impact on the local ecosystem. They kill native ants, who have learned to coexist with native vegetation, as well as contribute to the spread of pests to protect aphids in exchange for sugar-rich selection. But there were ants that have developed a defense mechanism to deal with the invaders.
A group of Stanford University, has discovered that the local brave the winter ants have learned to use chemical weapons to defend against waves of Argentine invaders.
"This is the first documented case where native species have successfully opposed the Argentine ant," - said Deborah Gordon, a biology professor at Stanford University who specializes in the study of ants and conducted a three-week summer class in which students are first noticed as winter ants use their venom.
To assess the lethality of venom and general combativeness winter ants, students held a series of "battles" in a small, palm-sized, glass containers in the laboratory.
They organized fights, involving up to 20 ants, with the balance of power between winter and Argentine ants varied. Also held gladiator fights one-on-one centimeter square "ring."
"It turned out that the winter ants secrete poison only in the case of a stressful situation, which seems to be caused by the fact that its production and use consumes a lot of energy," - said Gordon.
In open spaces, under natural conditions, the winter ants use the secretion in the event that the enemy is much superior to them numerically or for the protection of the queen and the colony.
Gordon is studying a population of ants in the Jasper Ridge Biological Preserve is already for 18 years. During this time, the territory was captured in a few times. Invaders invaded the sanctuary and were driven winter ants. But a few years ago, the winter ants began to counter-attack.
"It seems that the Argentine ants jostle ago, tree by tree" - said Gordon.
This change in the balance of power could occur as a result of colder weather and low rainfall, like winter, and do not like the Argentine ants.