To look at the tobacco budworm moth and its close cousin, you wouldn't be able to tell the fuzzy-looking, fingertip-size moths apart. But put males of each species as far as six car-lengths away from females, and even in the darkness of midnight they easily find their way to mates from their own species while ignoring females from the other species. Today, the genes that keep the species sexually isolated are no longer a mystery, thanks to research from North Carolina State University and the University of Utah.
NC State entomologist Dr. Fred Gould says the study, published today in the online edition of the Proceedings of the National Academy of Sciences, gives scientists a better understanding of how moths descended from a common ancestor and evolved distinctly different ways of communicating with mates.
Biologists have long been fascinated by the intricate way moths communicate through airborne chemicals known as sex pheromones. There are more than 100,000 species of moths, with each relying on its own unique pheromone blend, different in terms of the chemicals that make it up and the ratio of those chemicals. Females produce these precisely blended perfumes, and only males of their species respond to that sexual cue. Until now, scientists had a long list of potential genes and cellular molecules that could be responsible for each male finding only females of its own species.
In the PNAS paper, Gould and his collaborators explain how, through breeding, they moved a number of hypothesized sexual communication genes from Heliothis virescens, the budworm, into Heliothis subflexa, its close relative. They found that when they moved one specific small set of odorant receptor genes, the hybrid males understood and responded to the female budworm's pheromones in the same way that true male budworms respond.
The scientists cross-bred the related moths in their Raleigh laboratory and studied the moths' behavior in Utah wind
|Contact: Dee Shore|
North Carolina State University