Baby-Eating Freeloac1er Ants Are Welcome.
It might seem surprising that a colony of ants would tolerate the type of guests that gobble up both their grub and their babies, but research shows there likely is a useful tradeoff to accepting these parasite ants into the fold: they have weaponry that is effective against their host ants and a more-menacing intruder ant.
Rachelle Adams, assistant professor of evolution, ecology, and organismal biology at Ohio State University, Columbus, wanted to better understand the dynamics of the symbiotic relationship between parasitic Megalo-myrmex symmetochus ants and Sericomyrmex amabilis hosts. The host ants spend their lives farming fungus. The party crashers come in, do not contribute to the work, and eat both fungus and ant larvae. This lopsided arrangement can go on for years.
When they began the study, Adams and her collaborators knew that there were some obvious explanations for such behavior in nature. It could be that the parasites smell like the hosts and therefore go unnoticed, a situation called "mimicry." It could be that they smell like nothing and essentially are invisible intruders, a strategy called "insignificance."
However, when the researchers analyzed the odiferous hydrocarbons on the ants' bodies--the ant world's way of cueing the insects into whether they are encountering a nest mate or an outsider--they found that neither of these explanations told the entire story. The compounds on the intruders' backs were subdued, but that did not seem to account for the accepting behavior of the host ants.
Instead, the host/parasite relationship appears to be built on mutual protection from a more fearsome foe. The parasitic ants possess a volatile alkaloid-based venom that the host ants detect from a distance. The parasite ants' potent chemical weaponry is known to work against a more-lethal invader ant.
"Ifs likely a scenario where the enemy of your enemy is your friend," says Adams.
There are more than 250 species of these fungus-farming ants in the U.S. and Central and South America. The ants studied in this research live in Panama. 'These fungus farmers start little farms and care for the fungus garden by feeding it and protecting it from pathogens."
The crops are bountiful (more than what the host colony needs) so, when the parasites invade, it does not cause a tremendous amount of stress to either the fungus or ants--and, while they do eat some of the ants' proteinrich brood, they do not kill the queen and the host colony remains healthy.
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|Title Annotation:||INSECT ELONES|
|Publication:||USA Today (Magazine)|
|Date:||Jun 1, 2018|
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