“Ambidextrose” by Jay Werkheiser is from the October 2012 issue of Analog. It builds its situation from a problem of chemical incompatibility between human settlers of an alien planet and the exobiotic native life, useless to Earth organisms because the organic molecules are chemically wrong-handed. Wrong-handed sugars are nutritionally inert for humans, the amino acids poisonous.

The main character, Davis, survives a shuttle crash in a wilderness area of the planet Tau Ceti. He is from the single area on the entire planet that is inhabited by colonists (or so they believe), an island they call Haven. To establish the colony, the island had been sterilized of native life and seeded with Earth life.

At the time of the crash, Davis was exploring the wilderness beyond Haven with an eye for eventual expansion of the colony. He is rescued by an old woman, Lyda, who shouldn’t have been there; the colonists have no idea that any human lives outside Haven — indeed, that any human could survive outside of their colony. He learns that the mystery inhabitants of the wilderness don’t want to be found by his people, and they do not share his horror of the native vegetation — they have found ways of living with it, even making it digestible. He also learns that some of the native life is racemic — containing both left- and right-handed molecules.

In the process of adapting to the native biological conditions, Lyda’s people have developed a different culture. Marriage is unknown. Woman stay put, living in houses, and men are nomadic, visiting women only to mate. I was amused when Lyda tells Davis that her only visitors are women because she is too old to bear children. Really? No man, ever, visits a woman to just, say, talk?

Oh well. Some sort of remodeling of gender roles has become rote in SF, and it isn’t the main business of the story. It is suggested that this arrangement is an aid to survival in the wilderness of Tau Ceti because it increases genetic diversity. I would have imagined that other factors might also play a part, but Lyda shrugs and says men do what they do, and so we’ll have to take it on faith.

Some of Lyda’s people want to make sure that Davis never returns to his people, thus keeping their existence a secret from the colonists. Davis realizes that this means killing him. I’ll let you discover what happens from this point.

I like this story’s exploration of a less-worn SF problem of alien life and the consequences of biological incompatibility. It also, of course, has echoes of past conquests of other New Worlds. Werkheiser shows a new way of thinking just at its starting point, as Davis picks up a few clues from the alien life that he has heretofore had a great aversion toward, suggesting that the colony may awaken to possibilities other than conquest. A nice little story, if containing no great excitement.