Ant parasite turns host into ripe red berry, biologist...(and climb back up avoiding the treachero...)

In May 2005, when searching for a colony of the ants in a downed tree on Panama's Barro Colorado Island, Dudley was puzzled to see some members of the colony with bright red abdomens - something he, Yanoviak and Kaspari had never before seen. Taking several of the ants back to the lab and opening them up, Yanoviak discovered that the red abdomen was full of hundreds of nematode eggs.

"Like other ant biologists, I initially thought this was another species of Cephalotes," said Kaspari. "Robert didn't think so, and we made a bet over beers. Then Steve opened one up under the scope and - wow! I lost the bet."

Because the red abdomen clearly mimicked in both size and color the many red berries that attract birds, the biologists quickly suspected that the nematode had found a unique way to guarantee its transmission from ant host to bird host. The researchers spent the next couple of years trying to prove their hypothesis.

Yanoviak first consulted the world's authority on the nematodes that parasitize insects: George Poinar Jr., a former UC Berkeley researcher now at Oregon State University in Corvallis. Poinar and Yanoviak describ the new species of tetradonematid nematode, Myrmeconema neotropicum, in a paper to appear in the February 2008 issue of the journal Systematic Parasitology.

They also discovered that infected ants with red abdomens had been recorded before, and that some specimens resided in museum collections labeled as a variety of Cephalotes.

Yanoviak collected thousands of normal and infected ants in both Panama and Peru, near the Peruvian rainforest city of Iquitos, and demonstrated that, typically, about 5 percent of worker ants in a colony are infected. Cephalote
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