The Flight of the Iguana by David Quammen Read Free Book Online

some insects, worms, reptiles, and even a few species of mammal. By means of a mating plug, composed of glutinous secretions from his own body, the male of certain species manages, after having mated with a female, to literally glue her genital tract closed. This prevents her from mating with other males, and thereby increases his own relative reproductive success. Males of some roundworm species glue the females shut, after mating, in exactly this way. So do males among ground squirrels and moles. The traumatic inseminationpracticed by C. lectularius, biologists guess, arose as a way of circumventing that sort of mating plug.
    But hang on, it goes further. Now we come to the variant practiced by Xylocaris maculipennis. This libertine creature (for news of which I am indebted to a fascinating new book called A Natural History of Sex by the Canadian biologist Adrian Forsyth) is a close relative to the common bedbug, but its own special fame derives from taking traumatic insemination one step beyond. Instead of just stabbing-rape, X. maculipennis practices homosexual stabbing-rape. The males puncture and inseminate other males. In fact a male of X. maculipennis may be thus assaulted even while he is copulating with a female.
    No, I am not inventing this stuff from my own depraved imagination—but if you don’t believe me and Adrian Forsyth, you can consult a monograph in the journal Science, which adds the interesting information: “After homosexual rape in the anthocorid bug Xylocaris maculipennis, the sperm of the rapist enters the vas deferens of the victim and is used by the victim during copulation.” The punctured male serves as a proxy, in other words, a genetic courier, delivering the sperm of his attacker on to the next female with whom he himself mates.
    To an evolutionist, that bit of genetic advantage for the rapist might explain why such behavior exists. To a creationist, though, the whole subject must be inconvenient. Unlike the world’s bombardier beetles and cleaner wrasses, X. maculipennis would seem to lend itself poorly to the Proof-by-Design.
    The same ICR publishing house that brought us Bomby has served (by one account) as distributor of a tract titled “God’s Plan for Insects”—and for that matter another called “Unhappy Gays”—but I strongly doubt that either of those comes to grips with the phenomenon of homosexual rape among bedbugs. If X. maculipennis is another instance of God’s wisdom made manifestin the works of creation, I suspect that the sort of god manifested is not the one Duane T. Gish wants.
    My own instinct is to agree with Yogi Berra. If God does exist, He or She is probably patient enough to take the long view.

STALKING THE GENTLE PIRANHA

    An Intimate Link Between Amazon Fishes and Trees
    To get there you follow the Rio Aguarico downstream out of the Andes, past a petroleum boom town called Lago Agrio where the vultures congregate by hundreds over the municipal dump, and when the last cruising vulture disappears from view behind forest canopy at a bend in the river, you will find yourself surrounded by unspoiled Amazon jungle. The oil companies and the timber cutters and the would-be cattle barons haven’t gotten quite this far, quite yet. In the treetops will be toucans and monkeys; on a snag near the bank you might, with luck, see a basking anaconda. To go where you are headed you will be traveling, of necessity, by dugout canoe. If it happens to be a long sturdy log of a boat with a 55-horse Evinrude mounted on the rear, the downriver leg of the journey will take only a couple of days. The Rio Aguarico is a broad shallow river that flows caramel-brown with suspended sediment—same color and consistency as the upper Missouri during spring runoff—but the Zabalo, its tributary, is narrow and deep and black. The blackness signals dissolved acids, steeped from rotting vegetation or leached from soils in the swampy