Variety is the spice of life: too many males, too little time...

Apr 23, 2008

Female Australian painted dragon lizards are polyandrous, that is, they mate with as many males as they can safely get access to. This promiscuous behaviour is often found in species where male quality is dubious and there are high levels of infertility in the male population. Female painted dragons possess the remarkable ability to store sperm inside their reproductive tract that remain viable for a considerable amount of time, so that the sperm of different males actually compete with each other to fertilise her eggs.

Male painted dragons are highly distinctive and brightly coloured and what is particularly fascinating about them is that they occur in two different colours - red or yellow-headed. From an evolutionary perspective this seems intuitively puzzling as usually natural selection does an excellent job of removing inferior versions of an organism out of the ensuing population, ensuring its ultimate demise. With painted dragon lizard males however, both versions persist in the population, suggesting that each type of male somehow manages to acquire a mate and successfully reproduce equally well.

Mo Healey, Tobias Uller and Mats Olsson of Wollongong University, carried out female choice experiments on single males of different colours, and discovered that females did not preferentially associate with either coloured male. However, when females were allowed to choose between pairs of males of the same versus different colours, they preferred to associate with male pairs that were polymorphic, i.e., one red and one yellow male. The level of individual recognition in this species is unknown and often when males and females assess each other in the wild it is initially from a distance, meaning that visual cues are very important.

Healey et al. propose that by mating with one yellow and then one red male (or vice versa), female painted dragons are making sure that they are in fact mating with two different males and not the same male twice. This preference could therefore contribute to the maintenance of both male types within the population.

Source: Wiley

Explore further: Geometry, programmed death might have enabled evolution of multicellularity

add to favorites email to friend print save as pdf

Related Stories

Size doesn't matter if you're a sex sneak

Sep 10, 2014

Research into the mating behaviour of one of New Zealand's most unusual insects shows it doesn't always pay to be brave – sneaking sex can be just as effective.

A lack of leading ladies haunts game industry

Jun 19, 2014

Video game developers hyped upcoming titles featuring super-soldiers, assassins, bank robbers and secret agents at last week's Electronic Entertainment Expo. They all had one thing in common: They're men. ...

Recommended for you

Big science from small insects

19 minutes ago

Anniversaries are often a time to look back. But after taking stock of the past, it can be just as important to look to the future.

Battling superbugs with gene-editing system

17 hours ago

In recent years, new strains of bacteria have emerged that resist even the most powerful antibiotics. Each year, these superbugs, including drug-resistant forms of tuberculosis and staphylococcus, infect ...

Dwindling wind may tip predator-prey balance

Sep 19, 2014

Bent and tossed by the wind, a field of soybean plants presents a challenge for an Asian lady beetle on the hunt for aphids. But what if the air—and the soybeans—were still?

Environmental pollutants make worms susceptible to cold

Sep 19, 2014

Some pollutants are more harmful in a cold climate than in a hot, because they affect the temperature sensitivity of certain organisms. Now researchers from Danish universities have demonstrated how this ...

User comments : 0