The evolutionary benefit to females of spending time on their back

Aussie lizard rolls over to avoid sex
By Anna Salleh for ABC Science Online

Posted Wed Apr 29, 2009 3:34pm AEST
Updated Wed Apr 29, 2009 3:36pm AEST

Females of an Australian species of lizard rely on testosterone for a most unusual method of keeping amorous males off their back, researchers have found.

Evolutionary ecology Dr Devi Stuart-Fox of the University of Melbourne, and colleagues, report their findings online ahead of print publication in the Journal of Comparative Physiology A.

In most animals that use colourful displays for attraction, it's usually the male that's flashy, such as the peacock.

But the female Lake Eyre dragon lizard (Ctenophorus maculosus) is an exception. She displays a bright orange belly and throat during parts of her breeding season, which researchers think is driven by the hormone testosterone.

Interestingly, the colour features prominently when the female wants to put off a male from copulating with her.

Stuart-Fox and colleagues took a close look at a number of female lizards taken from Lake Eyre in South Australia and observed what happened when they were in the company of males.


Persistent males

When Lake Eyre lizards copulate the male bites the female's neck, climbs on top of her, wraps his tail around hers and inserts one of his two penises.

This can be hazardous to the health of the female because when the males bite them on the neck this can pierce the female's spine and result in death.

Therefore once the female's eggs have been fertilised, she will try to avoid mating. But males aren't easily put off.

"The males are really persistent," says Stuart-Fox. "They try and force copulation and they harass females all through the breeding season."

Unreceptive females scare off advancing males by taking on a threatening posture.

If this doesn't work, they throw themselves on their backs and reveal their bright orange underside.

"Males can't actually force themselves onto a female when she's on her back," says Stuart-Fox.


Sex steroid

Stuart-Fox also measured the levels of sex steroids in blood samples taken from the lizards over time.

Progesterone and testosterone usually decrease once female lizards are no longer receptive to mating, but not in the Lake Eyre dragon lizard.

"They maintain high testosterone levels all through the reproductive cycle including when they weren't receptive later in the cycle," says Stuart-Fox.

The researchers believe the testosterone is used to drive the female courtship rejection behaviours.


War of the sexes

Sexual conflict between persistent males and reluctant females has led to an evolutionary *** for tat involving all manner of behaviours, says Stuart-Fox.

"You get this runaway process where males evolve elaborate ways of trying to gain matings and females evolve elaborate ways of trying to avoid matings," says Stuart-Fox.

But she wondered about the evolutionary benefit to females of spending time on their back, which makes it difficult for them to run away from predators.

Especially given they live in a rather drab landscape, the bright orange could be a flag to predators that says "come and get me" , says Stuart-Fox.

But she says more recent studies have suggested predators do not recognise the brightly-coloured female lizards as prey.

So, says Stuart-Fox, the risk of being vulnerable to prey is much lower than the risk of having unwanted sex.

http://www.abc.net.au/news/stories/2009/04/29/2556114.htm

[portann]

I didn't want to draw that particular line to anyone else's attention but that is DEFINITELY the line that caught my eye the MOST. When I'm not wincing, I'm ROFL.

[jdwithhcv]

How on earth do they function with TWO little heads running the show?!?

[charm27]

I assume they function rather well! Two heads better than one! Confuscious say!
HAHA


Ive lost it I know....

[jdwithhcv]

hahahahahaha!

How do they decide which one to use?  Are they both the same or does one do things the other can't?  I'm intriegued!

jd

[charm27]

We will never know......I would assume its like having breasts.

Which one is better??
I know there must be a full moon coming.............

heheh

[ejoli]

When Lake Eyre lizards copulate the male bites the female's neck, climbs on top of her, wraps his tail around hers and inserts one of his two penises.

   What is this???  Foreplay??    Figures....

                                                -Libby

[can-do-man]

I thought men did to, sense my wife is always telling me to quit being a d-head

[jmjm530]

"You get this runaway process where males evolve elaborate ways of trying to gain matings and females evolve elaborate ways of trying to avoid matings,"
----------------------------------------------------
It's comforting to see how far we homo sapiens have evolved from lower life forms.

[GSDgirl]

ROTFLMFAO!!!!!!  You are all too much

[FlGuy]

A couple of things.
This has govenment funding written all over it.
I guess the female lizards are immune to headaches.

[charm27]

Science: Why two penises are so much better than one
24 November 1990 by GEORGIA MASON
Magazine issue 1744
Male lizards and snakes have to make a choice when they mate: which penis should they use? They have two. One is connected to their right testis, and one to their left. Now two biologists from the US have found that some lizards alternate their penises as each is depleted of sperm. In this way, they maximise their chance of fertilising a female.

Richard Torkaz and Joseph Slowinski of Miami University studied the lizard Anolis carolinensis. They found that the penis a lizard used depended on which they used last time they mated, and how long ago they last used it (Animal Behaviour, vol 40, p 374).

Torkaz and Slowinski believe that such behaviour can be explained by 'sperm competition'. Recently, zoologists have realised that competition for a female's favour does not simply involve fights among males or displays of bright plumage; it can continue inside the female's reproductive tract

[charm27]

Your right! Not a mention regarding a headache either!
HAH

[portann]

I'd been wondering off and on if they take turns like gentlemen, peck at each other or only come alive one at a time.

My headache is getting so bad just thinking about it...

[comeagain]

Now i understand that doors lyric "the minsters daughter is in love with a snake how lives by the side of the road!
Oh and the lyrics goes on with run, run, run not lay, lay, lay on back, back, back or is that another tune.
Come to think of that could have been love me two times babe,or the one when he is singing  I´m the Lizard King and I "can do"  anything  LOL!!

Yes Jm Jm Morrison or Jim Morrison as hes also was called surely was the Lizard King he´s just got to been having two, because he makes so many insinuations about runing and two and performing in any possible or impossible manner too many times

I´ll bet he had a Jenna aswell that couldn´t run when mr one too much double horny wanted her attention!!

ca

[jdwithhcv]

hahahahahahahaha!

[GoofyDad]

"One is connected to their right testis, and one to their left."

Not sure about the anatomy of a female lizzard, but in the species where I have some (albeit former) expertise, I'd say upper and lower would serve better than right and left. Unless you happen to be Mormon, maybe.

[Kristina538]

mmmmmmm... GD, we can count on you!!

Charm - I cracked up when I saw your additional post;  (I could imagine you suddenly googling "two penises") - thanks - never knew that myself..... hahahahaha - love it!!

As for the lizards - well, to keep the 'down under' competition alive,  I would expect nothing less from an Aussi male lizard, and the females probably learnt their tactics from their last OE trip to NZ.    Puts a new slant on orange-belly (much better than a yellow-belly - or are the two related)!!

Thanks Portann;  keep us informed...

[Bobby1952]

"When Lake Eyre lizards copulate the male bites the female's neck, climbs on top of her, wraps his tail around hers and inserts one of his two penises. "

   Whats the problem. I do this all the time. Without the second penis of course.

Bobby

[FlGuy]

"Whats the problem. I do this all the time. Without the second penis of course. "


There is a store, not too far away from where I work......  . "Batteries not included"

[ejoli]

  How come you KNOW where this store is?  And it is convenient to your job.... How nice for you!!!  :)

[FlGuy]

Google and Mapquest are great tools too.

[ejoli]

  What'd you do ?   Just google second penis?     That google is wonderfull!

[FlGuy]

My bad spelling it's not 'tools too' it's 'two tools'

[jdwithhcv]

Don't I know you from somewhere?

[Emilio44]

Argh, Great Southern Land you've got to love it!  I've seen these little treasures snap small tree branches with one bite so I can understand the importance of avoiding this kind of foreplay.Emi

[GoofyDad]

fore play? I thought we was talking two play.

FLguy - You callin' me a tool? An' I thought battry operated simulating devices was frowned upon down in your neck of the woods??? This I will mark as progress. Socks with tevas next, I'm tellin' ya.