Male Corn Earworm Moths, Helicoverpa Zea, Flies Too Soon During Courtship Race

By studying how female sex attractants make male moths warm up their flight muscles faster but take flight prematurely, University of Utah biologists are learning about how odor affects animal behavior.
Credit: José Crespo, University of Utah

The corn earworm can be found in temperate and tropical regions of the world. Mainly found in North America, it is a major agricultural pest. In their larvae stage, they are responsible for a large percentage of grade-out corn.

The species are identified by many different common names, depending on what the larva eats. Cotton bullworms are those that consume cotton. Corn eaters are called corn earworms. Tomato fruitworms are the larva that consumes tomatoes. The larva has also been known to consume many other crops.

Corn earworms regularly migrate into northern regions from southern regions depending on winter conditions.

Virgin male moths think they're hot when they're not

A University of Utah study found that when a virgin male moth gets a whiff of female sex attractant, he's quicker to start shivering to warm up his flight muscles, and then takes off prematurely when he's still too cool for powerful flight. So his headlong rush to reach the female first may cost him the race.

The study illustrates the tradeoff between being quick to start flying after a female versus adequately warming up the flight muscles before starting the chase. Until the next study, it remains a mystery which moths actually reach the females: the too-cool, quick-takeoff males or the males who wait until they're hot enough to take a shot. The latter may end up flying faster and more efficiently and win the race, despite a slow takeoff.