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Sexual deceit helps lady-boy lizards mate

The Augrabies Flat Lizard (Platysaurus broadleyi)

The Augrabies Flat Lizard (Platysaurus broadleyi) (Source: Martin Whiting)

Young, male lizards desperate to mate, access women and avoid attack from older males by pretending to be one of the girls, a new study says.

According to the study published in the Proceedings of the Royal Society B, young male Augrabies flat lizards (Platysaurus broadleyi) hide their colours so as to imitate plain, brown females.

"In this system the adult males are extremely colourful and extremely territorial and the females are a plain brown," says co-author Associate Professor Scott Keogh, of the School of Biological Sciences at the Australian National University.

"Young males purposefully only develop colours on their belly, so they reach sexual maturity by still looking like a female."

Imitating a female allows the juvenile lizards to mate with females, without being detected and driven away by the larger, territorial, adult males, who will chase and bite their young rivals.

These so-called she-males get a reproductive advantage by pretending to be females.

"If they develop colours on their back or side they would be visually identifiable as males and would never get close to the females at all," says Keogh.

Reproductive advantage

The sexual deception will give the young adult males a sexual advantage for a season.

"They probably get one full season where they look like the females but are sexually mature," says Keogh.

But while these young lizards might look like females, they still smell like males.

To prove this the researchers took animals from the wild and removed all pheromones and skin lipids that might signal gender.

They then relabelled a group of females and she-males with either male or female scent, before presenting them to typical adult males.

Males use their tongues to sample chemical scent and responded by courting she-males labelled as females, but not she-males labelled as males.

"Males are fooled by looks, but not by scent," says fellow researcher Dr Jonathan Webb, of the University of Sydney.

Trying to avoid a 'nosey tongue'


Other animals, such as fish, have been shown to use sexual deception to get an advantage in the wild, but this research is the first to show reptiles imitating the opposite sex through their appearance.

"What is special about this research is that we split the visual and olfactory cues," says Keogh.

This allowed the researchers to know that it was the colours of the young lizards that were deceiving the male adults, and not other factors.

Despite the advantage of imitating female, not all young male lizards perform the deceptive act.

"We think there are only some males that do this," says Keogh.

Knowing exactly how many young lizards imitate females is difficult because the area being studied, Augrabies Falls National Park in the South Africa, has the densest population of lizards worldwide.

Tags: animal-behaviour, biology, reptiles