Thursday, January 29, 2009

Argentine ants

Ants have invaded my reptile cage, the tropical humid one, to be more specific. Ants are in Berman's cage. Berman is a Solomon Islands Prehensile-tailed Skink, also known as a monkey tail skink, Corucia zebrata. He shares his cage with a Solomon Islands ground skink, Eugongylus albofasciolatus. Their tropical climate ecosystem that they call home is like an oasis in the Sahara desert for the Argentine ants. You know which ant I'm talking about. The one that gets in your kitchen trash, especially if there is something wet and sweet in it. The ones that invaded the trash cans in your junior high school. Pretty much the only ant you've ever seen unless you go camping and notice the bugs. Why are they so ubiquitous? Who are they?

Argentine ants (Linepithema humile, formerly Iridomyrmex humilis) do indeed come from Argentina. They have invaded fairly the whole world, probably with the help of people. Wherever they go they tend to displace native ants, which can affect plants that depend on native ants for pollination and lizards that specialize in native ants, such as the coastal horned lizard. But surprisingly, the ants don't pillage and plunder the native ant colonies as they sweep across the praries. All they need... is love.

Argentine ants are so successful because neighboring colonies do not fight with each other, like most ants do. Individuals roam freely among unrelated colonies and help each other with their work. They take each others' food without need for repayment. In this way they form supercolonies that can rapidly spread. Queens intermingle as well, often foraging with their workers. Argentine ants tend to upset the balance of native ants who form more tightly knit colonies that are constantly at war with the other tightly knit colonies. The Argentine ants can outcompete the native ants in searching for food and colony location. And if a battle should break out, unrelated colonies will defend each other. Their sheer numbers coupled with already heavily disrupted ecosystems, such as those along the California coast, create a recipe for disaster, with respect to native ant populations.

When I visited Biosphere II about 15 years ago, the experimental space station built near Tucson, the "scientists" had been out for at least a few years. As a budding biologist, I was fascinated with the idea of living in there, like living in one of my reptile cages! I thought the rain forest was beautiful and the grasslands looked lovely. I imagined how the scientists woke up every day and tended to their chickens and pigs and then took data on the plants and fish. As we toured around the outside of the Biosphere (no one was allowed in) and peeked into the windows, we couldn't help but notice the double row of busyness marching all along the entire base of the space capsule. Someone asked the guide about it and she said that was a recent problem and they hadn't worked out all the kinks yet. Apparently not, as it was one of the few animals to breech the security gate.

What can we learn from the Argentine ant? Give peace a chance and we can conquer the world? Perhaps, and yet... if all the peaceful people succeeded in ridding the world of war, would it be a better world? Maybe we need some warring people to keep us awake. A little bit of yang in the yin! Therefore, enjoy your battles because they may be your last! You might be overrun with boring peaceful people who want to share food and support each other!

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