Answer to the Monday Night Mystery: Corn Rootworm

Western Corn Rootworm
Western Corn Rootworm - Diabrotica virgifera

What was the mystery behind the mottled elytra?

Only the most serious corn pest in North America. Diabrotica virgifera is not only tremendously damaging to crop yields, it is also rather clever. Farmers have traditionally fought this insect by rotating corn out with soybeans every year. The insect lays its eggs in the soil, and in rotated fields the emerging young rootworms find themselves lost in a sea of inedible plants. Crop rotation was more effective than pesticides for keeping the rootworms in check. Yet some populations adapted, flying to soy fields to lay eggs so their offspring catch next year’s corn, and others have evolved resistance to genetically-modified corn. And whatever we come up with next? They’ll beat that, too.

A corn rootworm visits a soybean plant. Evolution is smarter than we are.

Anyway. 2 points to Laurie Knight for being the first to guess the order, and 8 points to Ainsley S for the genus & species.

Western Corn Rootworm

[thanks to Manfredo Seufferheld for the beetles!]

8 thoughts on “Answer to the Monday Night Mystery: Corn Rootworm”

  1. To be fair, resistance was seen only against 1st generation GMO corn (expressing a single protein – Cry3Bb) but not more recently commercialized varieties expressing multiple proteins (“stacks”). Resistance won’t come as easily to stacked GMO corn, although pretty much everyone agrees it will happen eventually and that additional modes of action will be needed. It’s the one insect targeted by GMO crops that, so far, appears to still have us chained to the mode-of-action treadmill.

    That said, this species is a marvelous example the ability of pest insects to adapt to nearly any obstacle placed in front of them. I wish it were that easy for certain species of tiger beetles!

  2. “Evolution is smarter than we are.”

    Perhaps a more accurate analogy is that evolution plays to a larger audience of randomness. Consider that only a small number of scientists generate small challenges but millions fight for their life.

    “Move out! You’re Marines now. You improvise. You adapt. You overcome”
    Gunnery Sgt. Tom Highway

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