Navigation Links
Penguin males with steady pitch make better parents

AUDIO: Male penguins serenade prospective mates with a call known as an 'ecstatic display call.'

Click here for more information.

Durham, NC How does a female penguin choose a mate? Courtship calls help females decide which males are likely to be devoted dads, says a study in the journal Behaviour.

Antarctic penguins come on land for just a few short months each summer to breed and raise their chicks. Raising a family in the coldest place on earth is no small feat. Adelie penguins pull it off by tag-team parenting, the researchers explained. Males and females take turns incubating the eggs and guarding the chicks while their mate forages for food.

Males arrive first to claim a territory and build a nest. When the females arrive, the males serenade prospective mates by throwing their heads back, pointing their beaks to the sky, and emitting a series of hoarse trills and squawks.

"They're not musical calls they sound like a cross between a donkey and a stalled car," said author Emma Marks of the University of Auckland. Penguin calls may not be music to our ears, but to penguin females they hold clues to a male's paternal potential, Marks and colleagues report.

After choosing a mate the female lays two eggs and returns to sea, leaving the male alone to tend the egg until she returns to take the next shift. For the first two weeks penguin dads do the bulk of babysitting duty without breaking to eat. By relying on stored fat reserves, father penguins can lose more than 20% of their body weight over the course of the summer breeding season, the researchers said.

"It's a pretty arduous task, especially for the males," said Marks. "If a male doesn't have enough fat to last these fasts, he may have to abandon the eggs and go to sea before the female can make it back. So it's imperative that the female pick a male in good condition," she added.

The researchers wanted to know how courtship calls help a penguin female choose the father of her chicks. "We knew that females preferred some males over others. But we didn't know what traits females were using to choose a good mate," said co-author Dianne Brunton of Massey University in New Zealand.

"If she chooses a male with a particular kind of call, does she have a better chance of successfully raising chicks?" Marks asked.

To find out, Marks traveled to Antarctica's remote Ross Island, summer home to half a million Adelie penguins. Over the course of the next three months she weighed dozens of males and recorded their calls with a handheld microphone. She also noted how successful they were at attracting mates and raising chicks.

When the researchers examined the calls, they found that steady frequency over the longest part of the call an extended chattering in the middle of the male's display best predicts male buffness and breeding success. "It's as if females are listening to the stability of the call," said Marks.

Males with more consistent pitch were snatched up more quickly. These males were also heavier and more successful at raising chicks, the researchers found. "The fat surrounding the male's voice box changes what his call sounds like," said Brunton. "We don't yet know the physiological mechanism for call production, but body fat appears to stabilize their calls," Marks added.

By listening to male courtship calls, a female can tell how fat a male is and what kind of father he'll be, Brunton explained. Fatter males make better fathers because they have the energy reserves to endure long fasts, so are less likely to leave the nest and desert their chicks.

"A fat male is a good choice for a female because males do so much of the offspring care," said Brunton. "They're able to incubate the eggs for longer and use up their fat stores, while skinny males aren't able to do that."

The researchers also wondered if males were always honest about their potential as caring fathers, or merely bluffing to attract a mate. "What if the guy calls, and it turns out he's a skinny bird pretending to be a fat bird, making himself sound better than he really is?" said Marks.

"Females can't judge how fat a male is just by looking at him," said Brunton. "How fat he looks depends on how he's standing and how fluffed up his feathers are."

A male who lies about his paternal commitment might increase his chances of passing on his genes, said co-author Allen Rodrigo, Director of the National Evolutionary Synthesis Center in Durham, North Carolina. For that reason, females are likely to be on the lookout for the most honest indicators of paternal potential, he explained.

As penguin dads lost weight over the chick-rearing season, their calls changed too, Marks found. "So a skinny male is unlikely to be able to pretend he's a big fat male. He can't fake it," said Marks.


Contact: Robin Ann Smith
National Evolutionary Synthesis Center (NESCent)

Related biology news :

1. A happy new year for penguins
2. Penguins marching into trouble
3. Ancient penguin DNA raises doubts about accuracy of genetic dating techniques
4. Penguins and sea lions help produce new atlas
5. Study first to pinpoint why analgesic drugs may be less potent in females than in males
6. Reproductive life of male mice is increased by living with females
7. Caffeine appears to be beneficial in males -- but not females -- with Lou Gehrigs disease
8. Caffeine appears to be beneficial in males -- but not females -- with Lou Gehrigs disease
9. Sexual harassment from males prevents female bonding, says study
10. Hidden genitalia in female water striders makes males sing
11. Not 1, but 2 kinds of males found in the invasive round goby
Post Your Comments:
Related Image:
Penguin males with steady pitch make better parents
(Date:11/12/2015)... Nov. 12, 2015  A golden retriever that stayed ... dystrophy (DMD) has provided a new lead for treating ... the Broad Institute of MIT and Harvard and the ... . Cell, pinpoints a protective ... the disease,s effects. The Boston Children,s lab of ...
(Date:11/10/2015)... , Nov. 10, 2015  In this ... the basis of product, type, application, disease ... in this report are consumables, services, software. ... are safety biomarkers, efficacy biomarkers, and validation ... report are diagnostics development, drug discovery and ...
(Date:11/4/2015)... York , November 4, 2015 ... a new market report published by Transparency Market Research "Home ... Growth, Trends and Forecast 2015 - 2022", the global home ... US$ 30.3 bn by 2022. The market is estimated ... forecast period from 2015 to 2022. Rising security needs ...
Breaking Biology News(10 mins):
(Date:11/24/2015)... Switzerland (PRWEB) , ... November 24, 2015 , ... ... plant and the environment are paramount. Insertion points for in-line sensors can represent ... has developed the InTrac 781/784 series of retractable sensor housings , which ...
(Date:11/24/2015)... , Nov. 24, 2015 HemoShear ... on discovering drugs for metabolic disorders, announced today ... to its Board of Directors (BOD). Mr. Watkins ... of Human Genome Sciences (HGS), and also served ... Jim Powers , Chairman and CEO ...
(Date:11/23/2015)... , Nov. 24, 2015 Women with a ... CT exams face a higher risk of lung cancer than ... presented next week at the annual meeting of the Radiological ... --> --> Lung nodules ... classified as solid or subsolid based on their appearance on ...
(Date:11/23/2015)... The royalty-free a greement a llows ... 112 low- and m iddle-i ncome ... --> The Medicines Patent Pool (MPP) today announced its ... with Bristol-Myers Squibb for daclatasvir, a novel direct-acting antiviral that ... virus.  The royalty-free licence will enable generic manufacture of daclatasvir ...
Breaking Biology Technology: