Another sexual attraction is po...( The coming summer vibrates with expres...)

The coming summer vibrates with expressions of insect love and desire. The cicada's songs or the butterflies' bright colours are examples of how an emitting sex attracts conspecific members of the responding sex. Moth odours (pheromones), though less conspicuous for us humans, are also signals by which females guide males towards them, even on the darkest nights. Such mating recognition systems tend to be very specific, hence they are thought to play a major role in the evolution of mating barriers and in the formation of new species.

The fact that conspecific males and females recognize each other by their common use of a highly specific "language" is likely to decrease the fitness of mutants that might use slightly different signals. Such "atypical" individuals would either - and most probably - die without leaving any offspring, or - in the unlikely event that they find a mutant partner - they might found a new line that may eventually become a new species. As such, the offspring of such parents would inherit the mutant communication system of their parents, which could "spark" the divergence leading to the formation of a new species.

The European corn borer, Ostrinia nubilalis, is a model species that is particularly well-suited to study the first steps along the road to speciation and the deep mysteries of reciprocal attraction - or lack thereof - between potentially interfertile individuals. Indeed, two types of females and two corresponding types of males coexist within this species: one type communicates with the so-called "E" pheromone while the other communicates with the "Z" pheromone. Although hybrid matings produce perfectly viable offspring, both types very rarely mate in nature. At a first glance, it is tempting to believe that this is due to their different pheromones.

However, in a study published in the June 20th issue of the online, open-access journal PLoS ONE, researchers from the Institut National de la Recherch
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Contact: Sergine Ponsard
ponsard@cict.fr
Public Library of Science
19-Jun-2007