Male scent drives moth's evolution

It may be these different smells that contribute to the formation of new species. This is shown in a new study from Lund University in Sweden.

It was previously known that odorant substances, so-called pheromones, play a role in the sex lives of many animals.

When a female moth wants to attract a male to mate with, she emits scents that males can perceive from long distances. But males also have scents that are attractive to females in varying degree. For many years, ecologists at Lund University have pursued research on precisely how individuals, of both sexes, use pheromones.

In a new study, phD student Jean-Marc Lassance and Professor Christer Löfstedt at the Division of Chemical Ecology have examined how pheromones affect the choice of partner in a moth species called the European corn borer.

The corn borer is a small moth with a wingspan of 2-3 centimeters. The species has a natural distribution in Southern and Central Europe, and it also occurs in Southern Sweden. It is often considered a serious pest, especially of corn (maize). By understanding its life cycle and how it reproduces, and with the help of the species' own olfactory substances instead of chemical poisons, damage to grain could be reduced.

But research on the corn borer also made Lassance and Löfstedt wonder whether scents contribute to the evolution of new species. The two Lund researchers have analyzed the consistency of the olfactory compounds and also the genes of moth males from France, Hungary, and Slovenia, among other countries, and discovered that the males' pheromones differ. The male corn borer in France smells different from male moths in Slovenia or USA.

The Lund scientists have reported that females can use scents to distinguish where males come from, their age, and perhaps even how good their genes are for mating and reproduction. Lassance and Löfstedt propose that differences in pheromones may be a force that impels evolution among moths and butterflies. Females among the corn borers studied seem to prefer older males that produce a particular typical pheromone. This choice of partner increases their isolation from corn borers from different areas, which in turn can reinforce further the development of new species.

“Our research findings may come to alter our understanding of the role of olfactory compounds in the evolution of species,” says Jean-Marc Lassance. “We show how males' and females' scent production is governed by the same genes and how they use similar pheromones in a chemical dialogue during mating.”

The researchers' study is now published in the scientific journal BMC Biology.

For more information, please contact Jean-Marc Lassance, phone: +46 (0)46-222 20 484 or Christer Löfstedt, phone: +46 (0)46 – 222 93 38 (mailto:jean-marc.lassance@ekol.lu.se or christer.lofstedt@ekol.lu.se)

Pressofficer Lena Björk Blixt; Lena.Bjork_Blixt@kanslin.lu.se; +46-46 222 71 86

Link to the article in BMC Biology: http://www.biomedcentral.com/1741-7007/7/10

BMC Biology 2009, 7:10; 3 March 2009