The cricket world is not above using chemical enhancement in a bid to get the girl, according to an Australian study.
Insect skins, or cuticles, are coated with a layer of fatty acids that prevent water loss. The composition of these chemicals can also provide information about species identity, sex and past mating activity.
The study, by researchers at the University of Western Australia's Centre for Evolutionary Biology, shows that these chemicals can undergo rapid changes in composition and reflect changes to an individual's social status.
In the research, published today in the Proceedings of the Royal Society B, the authors show for the first time in any species, males undergoing short-term changes in their chemical 'make-up' in response to a dip in dominance status.
"Male dominance status can be frequently challenged and is therefore a potentially unstable trait," co-authors Dr Melissa Thomas and Professor Leigh Simmons write.
"For pheromones to honestly reflect a male's current social status, they would be required to mirror such changes in status."
For the study, Thomas and Simmons analysed the chemicals that the Australian field cricket (Teleogryllus oceanicus) produces on its skin.
Equivalent to exotic plumage
Male crickets were found to alter the chemical composition of their fatty coat in response to aggressive interactions with other males.
Thomas says in mating terms those chemicals - the cuticular hydrocarbons - are the equivalent of exotic plumage on male birds and play a similar role in attracting females.
The study shows that dominant males, on losing a fight with another dominant male, create a chemical signature resembling that of a subordinate male.
This could help compensate for their lost fertilisation success, Thomas says.
For the study the researchers first ranked the crickets through a series of fights. Only those that won all their bouts, the dominant males, and those that lost all their bouts, the subordinates, were used in the study.
The status of the crickets was then forcibly changed by placing two dominant crickets and two subordinate crickets together and allowing them to fight.
Thomas says it was easy to determine which cricket had won as subordinate males would display avoidance behaviour while the winning dominant male would produce an aggressive victory song.
Samples of the cuticular hydrocarbon were taken and analysed, and showed that previously dominant males quickly changed their hydrocarbon profile to more closely resemble a subordinate male.
Thomas says this chemical change could help the previously dominant crickets increase their mating success.
"Although males cannot force copulations, dominance status does determine a male's ability to attract females via acoustic signals," she says.
"Dominant males will produce calling and/or courtship songs in the presence of subordinate males, whereas subordinate males are suppressed in their courtship song through intermittent attacks by the nearby dominant male."
Like wearing strong cologne
In nature subordinate males appear to compensate for this disadvantage by producing a relatively larger proportion of certain cuticular hydrocarbons that have previously been shown to increase male attractiveness to females, a bit like human males wearing strong cologne.
But in the study subordinate males that won a fight did not change their chemical profile to match that of a dominant cricket.
Thomas says this suggests males of different social competitiveness are either genetically predisposed to this chemical plasticity, or that social experience can strongly influence a male's decision in subsequent interactions.
But she says further research is needed to find out which of these factors is the dominant influence for what happens in crickets.
"It's pretty complicated for a little insect," says Thomas.
She says understanding how the hydrocarbons are used and work is the first step in discovering whether this knowledge could have a role in pest management.