Squash plays an important role in the diets and cultures of Native Americans and Indigenous peoples of Mexico. But a half-inch long, flat-backed pest called Anasa tristis can wreak havoc on the plants if left unchecked.
Now, a paper in the journal Current Biology describes chance discovery that solves a long-standing mystery about squash bugs and could help control their populations.
Squash bugs drink sap, causing plants like pumpkin, squash and melon to wilt and sometimes die.
Like many insects, they rely on special bacteria to help them digest food; unlike many other insects, they don’t provide this key bacteria to their newborns.
Nymphs have only five days to find a source of the bacterium Caballeronia themselves or die trying.
A spur-of-the-moment side experiment by an Emory University researcher showed nymphs have an innate way to find adult dung to feed on, even if they lose their antennae and have to rely on eyesight. But without the sense of smell antennae provided, they cannot sense if the excrement contains Caballeronia.
Graduate student and co-author Jason Chen was working with adult squash bugs and had tagged the Caballeronia bacteria inside them with a fluorescent protein as part of a different experiment. As he ended his day, he decided, almost of a whim, to add throw some nymphs in with the adult.
While he was gone, the adult answered nature’s call. When he returned, every nymph in the area was busily feeding on the adult’s excrement. A few days later, their guts glowed with Caballeronia.
This discovery could lead to pesticide-free ways to manage the insects, possibly by releasing modified versions of the bacterium that squash bugs bodies cannot use.
