Yes, if our genes are close enough. Otherwise, not. That's the word from a new study of the Argentine ant, an invasive pest that forms gigantic "super-colonies" in California. Since Argentine ants somehow entered the state about 100 years ago, they quickly became ant numero uno.
Argentine ants also pose a biological conundrum. Many ant colonies fight territorial wars against neighboring colonies, which has the fringe benefit of serving to naturally control ant populations. But the Argentine ant does no such thing. In fact, biologists say a super-colony extends from San Diego to the Bay area, containing an uncountable number of inhabitants.
Why don't adjacent nests fight each other?
Research just published finally offers an answer: The Argentine ant recognizes and cooperates with genetically similar ants, even those living in other nests, but it tries to kill ants with different genetics.
For some reason, the Argentine ant has remained genetically uniform during its spread through the state, and that uniformity is key to the super-colonies. "Our results are strong evidence that lack of genetic diversity permits super-colonies to arise," according to Melissa Thomas, who was a postdoctoral fellow with Holway during the study. "Workers cannot differentiate between nest mates and non-nest mates if they all seem the same. So ants from different nests in the same colony do not fight with each other."
Studies of the Argentine ants, Holway adds, shows "well-defined territories, and colony boundaries that are defined both behaviorally and genetically." These boundaries have probably lasted for years or more, he adds.
And how do the ants recognize outsiders? Holway says a third co-author, Neil Tsutsui, is identifying compounds in their external skeleton that "give workers from the same colony a unique odor."
The unusual super-colony structure confers a major survival advantage to its inhabitants, Thomas explained. "Territory defense is expensive both in time and workers. If nests invest this time and workforce into collecting resources and raising larvae instead of defending territories, then colonies should grow at a much faster rate." In the Argentine ant super-colonies, the mortality of the border battles may not significantly affect the total population.
We cannot resist mentioning the human parallel: enlisting provocateurs to cause enemies to fight among themselves. With ants, it could be easy and ethical, once you decipher the signals of psycho-chemical warfare.
http://whyfiles.org/shorties/221ant_invaders/
Argentine ants also pose a biological conundrum. Many ant colonies fight territorial wars against neighboring colonies, which has the fringe benefit of serving to naturally control ant populations. But the Argentine ant does no such thing. In fact, biologists say a super-colony extends from San Diego to the Bay area, containing an uncountable number of inhabitants.
Why don't adjacent nests fight each other?
Research just published finally offers an answer: The Argentine ant recognizes and cooperates with genetically similar ants, even those living in other nests, but it tries to kill ants with different genetics.
For some reason, the Argentine ant has remained genetically uniform during its spread through the state, and that uniformity is key to the super-colonies. "Our results are strong evidence that lack of genetic diversity permits super-colonies to arise," according to Melissa Thomas, who was a postdoctoral fellow with Holway during the study. "Workers cannot differentiate between nest mates and non-nest mates if they all seem the same. So ants from different nests in the same colony do not fight with each other."
Studies of the Argentine ants, Holway adds, shows "well-defined territories, and colony boundaries that are defined both behaviorally and genetically." These boundaries have probably lasted for years or more, he adds.
And how do the ants recognize outsiders? Holway says a third co-author, Neil Tsutsui, is identifying compounds in their external skeleton that "give workers from the same colony a unique odor."
The unusual super-colony structure confers a major survival advantage to its inhabitants, Thomas explained. "Territory defense is expensive both in time and workers. If nests invest this time and workforce into collecting resources and raising larvae instead of defending territories, then colonies should grow at a much faster rate." In the Argentine ant super-colonies, the mortality of the border battles may not significantly affect the total population.
We cannot resist mentioning the human parallel: enlisting provocateurs to cause enemies to fight among themselves. With ants, it could be easy and ethical, once you decipher the signals of psycho-chemical warfare.
http://whyfiles.org/shorties/221ant_invaders/
