The Animal Kingdom Is Dominated By Body-Snatching Wasps

When talking about whether theology has anything to learn from science, the British biologist J. B. S. Haldane used to quip that God must have “an inordinate fondness for beetles.”

He had a point. Around 380,000 species of beetle have been described, which accounts for a quarter of all known animal species. There are more species of ladybugs than mammals, of longhorn beetles than birds, of weevils than fish. Textbooks and scientific papers regularly state that beetles are the most speciose group of animals; that is, there are more of them than there are of anything else.

But Andrew Forbes, from the University of Iowa, thinks that this factoid cannot possibly be right.

In a new paper, published online as a pre-print, Forbes and his colleagues argue that nature’s apparent beetlemania is more a reflection of historical bias than biological reality. Beetles are often conspicuous, shiny, beautiful, and varied—qualities which meant that 19th-century naturalists like Charles Darwin collected them for sport, and eagerly compared the size of their collections. Thanks to their inordinate fondness for beetles, we have a disproportionately thorough picture of the group’s diversity. The same can’t be said of other groups of insects that are smaller on average, harder to study, and less charismatic.

Forbes studies parasitoid wasps. These creatures use their stingers to lay eggs in (or on) the bodies of insects and other hosts. The grubs, upon hatching, devour their hosts alive, sometimes commandeering their minds and changing their behavior, and sometimes bursting out of their desiccated carcasses. There’s a wasp that takes cockroaches for walks after turning them into docile zombies, a wasp that forces spiders to spin a protective cocoon all while sucking them dry, a wasp that turns caterpillars into half-dead, head-banging bodyguards, a wasp that conscripts ladybirds into acting as babysitters.

Their lives are grisly and sinister, but their abilities are incredible.

No one really knows how many of them there are. There aren’t many scientists who specialize in studying them. They can spend much of their lives hidden inside the bodies of other insects. And since they specialize in body-snatching, they can be incredibly small. The smallest of them, the fairy wasps, parasitize millimeter-long insects, and are themselves no bigger than a single-celled amoeba. This means that when scientists try to catalog the number of insects in a given area, they often ignore all but the …read more

Source:: The Atlantic – Science

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