Ants forced to con birds in worm's 3-way reproductive strategy

San Francisco Chronicle

http://www.sfgate.com/cgi-bin/article.cgi?file=/c/a/2008/01/17/MNF2UGFVM.DTL&type=printable

David Perlman, Chronicle Science Editor

January 17, 2008

Consider the remarkable strategy of a lowly parasitic worm in the tropics that
seeks to spread its progeny far and wide:

The tiny worm infects a tropical ant, and turns its black belly red.

The ant waves its belly up high, and it looks just like a ripe, red berry.

A bird gobbles up what it thinks is a berry; it flies away and its droppings
fall to the ground.

From those droppings come thousands of the parasite's eggs, and behold! They
hatch and a new population of nematode worms emerges, ready to infect more ants
that turn more ant bellies red that attract more birds to eat the red bellies,
and so on and on and on.

The parasite is a species of nematode also known as roundworms, the ant is
called Cephalotes atratus and it lives high in the canopy of tropical
rainforests from Peru to Panama, while just any old bird will do in this bizarre
example of co-evolution that has brought all three - the worm, the ant and the
bird - together....

"It's just crazy that something as dumb as a nematode can manipulate its host's
exterior morphology and behavior in ways sufficient to convince a clever bird to
facilitate transmission of the nematode," said UC BERKELEY EVOLUTIONARY
BIOLOGIST ROBERT DUDLEY, one of the researchers who discovered the example of
three-way evolution....