These images from an infrared video show a moth’s increasing temperature — turning from purple to red to orange and yellow — as it shivers to warm up its flight muscles. A University of Utah study found that when naive male moths are exposed to female sex attractant, they start shivering faster to warm up, but then take off prematurely before they can attain maximum flight power. Credit: José Crespo, University of Utah
Talk about throwing yourself into a relationship too soon. 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.
“What happens before flight has not been well studied,” says José Crespo, a University of Utah doctoral student in biology and first author of the new study, published online June 7 in the Journal of Experimental Biology. “To me, the story is you have a behavior – pre-flight warmup – that is switched on by smell.”
Senior author Neil Vickers, professor and chairman of biology at the University of Utah, says: “In many insects, moths in particular, all of their adult lives are affected by odor – all the activities they engage in that you and I see at night at the porch light are things typically affected by odor.”