Parasitic worms make sex worthwhile
How's that for a title? That came from the PR department of Indiana University. The actual title of the article that appears in the journal Current Biology is The Geographic Mosaic of Sex and the Red Queen . Quite a bit of difference between the two titles, eh? The article is based on a very elegantly designed series of experiments conducted on New Zealand's South Island, in Lake Alexandrina and Lake Kaniere. The test subject was snails, similar to the one I photographed on Saturday, but these snails are fully aquatic and often infested with worms. Ewww. The parasitic worms are a genus of trematode worms called Microphallus , and infest the snails in both lakes. What makes this interesting is that the worms need to be ingested by ducks for the next stage of their life cycle. That can only happen if the snails live in shallow water where the ducks feed. Snails dwelling in deeper water still get infested with the worms, but it ends there. The worms never mature (since they don...