New study finds that male lizards use different tactics to win the ladies

October 21, 2013
An Eastern Water Skink (Eulamprus quoyii). Credit: Martin Whiting

( —New collaborative research conducted by Macquarie University and the Australian National University on a common Australian lizard, the Eastern Water Skink, has revealed that sexual selection, the process whereby certain individuals gain a reproductive advantage, likely promotes the evolution of 'floater' and 'territorial' behavioural reproductive tactics in males.

The researchers studied six marked populations of the Eastern Water Skink in large naturalistic outdoor enclosures. They followed the movements and behaviour of males during the breeding season, and used genetic paternity testing to determine .

"Ultimately, we were interested in what make a successful male lizard" said lead researcher Daniel Noble.

"As it turns out, large males that adopt either a territorial-like tactic (where they defend a fixed area), or a 'floater' or 'sneaker'- like tactic (with no defense of a particular space, but who move over a wider area), father the most offspring and therefore have the highest fitness."

Alternative reproductive tactics (ARTs) have been studied in a wide range of species. However, few studies document ARTs in species where there are no distinguishing features separating males from each other. This study demonstrates that ARTs can be driven by behaviour alone.

Noble explains "Males adopting ARTs are often distinct from one another in terms of body size, colouration, or the presence and size of armaments such as horns. We know very little about ARTs in nondescript species.

"What makes these results particularly interesting is that we simply quantified behavioural variation to test whether there was evidence of disruptive selection on trait combinations predicted to be associated with ARTs in water skinks.

"In many systems, we cannot take this approach because polymorphic species (that is, males with different coloration) lack intermediate phenotypes. Our results have important implications for understanding the early evolution of ARTs because they suggest selection starts by acting on more labile behavioural traits, which allow to gain access to mating opportunities through different mechanisms."

The authors have documented a rare case of ARTs evolving through selection on suites of male behaviours. This cryptic system may be more common than currently understood, and underscores the importance of behaviour as an ART in its own right.

The research paper has been published in full online in the American Naturalist.

Explore further: 'Paranoia' about rivals alters insect mating behavior

More information: Daniel, W. et al. Behavioral and Morphological Traits Interact to Promote the Evolution of Alternative Reproductive Tactics in a Lizard (2013), The American Naturalist.

Related Stories

'Paranoia' about rivals alters insect mating behavior

August 8, 2011

Scientists at the University of Liverpool have found that male fruitflies experience a type of 'paranoia' in the presence of another male, which doubles the length of time they mate with a female, despite the female of the ...

Shorebirds prefer a good body to a large brain

July 18, 2013

In many animal species, males and females differ in terms of their brain size. The most common explanation is that these differences stem from sexual selection. But predictions are not always certain. A team of researchers ...

Doing it to death: Suicidal sex in 'marsupial mice'

October 7, 2013

Imagine if you only had one shot at passing on your genes before you died. It happens more often in the natural world than you might expect: suicidal reproduction – where one or both sexes of a species die after a single ...

Recommended for you

Trade in invasive plants is blossoming

October 3, 2015

Every day, hundreds of different plant species—many of them listed as invasive—are traded online worldwide on auction platforms. This exacerbates the problem of uncontrollable biological invasions.

Ancestral background can be determined by fingerprints

September 28, 2015

A proof-of-concept study finds that it is possible to identify an individual's ancestral background based on his or her fingerprint characteristics – a discovery with significant applications for law enforcement and anthropological ...

Bat species found to have tongue pump to pull in nectar

September 28, 2015

(—A trio of researchers affiliated with the University of Ulm in Germany and the Smithsonian Tropical Research Institute in Panama has found that one species of bat has a method of collecting nectar that has never ...


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.