Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Sexy sons thanks to mom

It is not the superior genes of the father, but the mother’s resource investment in the eggs that makes Zebra Finch males particularly attractive. A Swiss-Australian research team lead by evolutionary ecologists at the University of Zurich has challenged the theory that females mate with superior males to obtain good genes for their offspring.

In Zebra Finches, as in most other bird species, both parents contribute to offspring rearing. The social partner of a female, however, is not always the biological father of the young. If the opportunity arises, females will choose to pair with partners other than their primary mate – with the interesting result that the offspring of different fathers have different qualities. And, as evolutionary ecologists from the University of Zurich and biologists from Macquarie University in Sydney have discovered, offspring sired by an extra-pair partner develop larger color ornaments and are more attractive to females than their social half-brothers.

A Zebra Finch male displaying his color ornaments.

Extra-pair males are not more attractive

Up to now, the quality differences between social and extra-pair offspring have generally been assumed to reflect the genetic superiority of the extra-pair male. Indeed, females are believed to engage in extra-pair copulation with genetically superior males to obtain better genes for their offspring. Now, Barbara Tschirren, professor for evolutionary ecology at the University of Zurich, and her team have challenged the idea of the exceptional male. In a study published in «Proceedings of the Royal Society» the researchers demonstrate that – despite the observed quality differences – the fathers of attractive sons are neither better looking nor genetically superior.

The first eggs receive preferential treatment

According to the study, attractive sons are not the result of exceptional genes; rather, their enhanced ornamentation is due to the mother’s investment in the eggs. Tschirren was able to demonstrate that maternal resource investment decreases steadily over the course of the laying sequence of a Zebra Finch, with eggs laid early in a clutch being larger and containing more nutrients and hormones. Favoring early eggs and the first hatchlings is a worthwhile investment for the mother as these offspring have a demonstrably higher chance of survival. «It appears that there is strong competition among males to fertilize these valuable eggs early in a female’s laying sequence», explains lead author Barbara Tschirren. «They try to exploit the female’s egg investment bias to ensure a head start for their own offspring.» She hypothesizes that sperm competition might decide the battle, with males with faster sperm being able to fertilize the most valuable eggs.

Barbara Tschirren, Erik Postma, Alison N. Rutstein, Simon C. Griffith: When mothers make sons sexy: Maternal effects contribute to the increased sexual attractiveness of extra-pair offspring, in: Proceedings of the Royal Society B, 28 September 2011, DOI:10.1098/rspb.2011.1543
Prof. Dr. Barbara Tschirren
University of Zurich
Institute of Evolutionary Biology and Environmental Studies
Phone: +41 44 635 47 77

Nathalie Huber | idw
Further information:

Further reports about: Tschirren bird species color ornaments finch zebra zebra finch

More articles from Life Sciences:

nachricht Novel mechanisms of action discovered for the skin cancer medication Imiquimod
21.10.2016 | Technische Universität München

nachricht Second research flight into zero gravity
21.10.2016 | Universität Zürich

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: New 3-D wiring technique brings scalable quantum computers closer to reality

Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.

"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...

Im Focus: Scientists develop a semiconductor nanocomposite material that moves in response to light

In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.

A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...

Im Focus: Diamonds aren't forever: Sandia, Harvard team create first quantum computer bridge

By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.

"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...

Im Focus: New Products - Highlights of COMPAMED 2016

COMPAMED has become the leading international marketplace for suppliers of medical manufacturing. The trade fair, which takes place every November and is co-located to MEDICA in Dusseldorf, has been steadily growing over the past years and shows that medical technology remains a rapidly growing market.

In 2016, the joint pavilion by the IVAM Microtechnology Network, the Product Market “High-tech for Medical Devices”, will be located in Hall 8a again and will...

Im Focus: Ultra-thin ferroelectric material for next-generation electronics

'Ferroelectric' materials can switch between different states of electrical polarization in response to an external electric field. This flexibility means they show promise for many applications, for example in electronic devices and computer memory. Current ferroelectric materials are highly valued for their thermal and chemical stability and rapid electro-mechanical responses, but creating a material that is scalable down to the tiny sizes needed for technologies like silicon-based semiconductors (Si-based CMOS) has proven challenging.

Now, Hiroshi Funakubo and co-workers at the Tokyo Institute of Technology, in collaboration with researchers across Japan, have conducted experiments to...

All Focus news of the innovation-report >>>



Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

Agricultural Trade Developments and Potentials in Central Asia and the South Caucasus

14.10.2016 | Event News

World Health Summit – Day Three: A Call to Action

12.10.2016 | Event News

Latest News

Resolving the mystery of preeclampsia

21.10.2016 | Health and Medicine

Stanford researchers create new special-purpose computer that may someday save us billions

21.10.2016 | Information Technology

From ancient fossils to future cars

21.10.2016 | Materials Sciences

More VideoLinks >>>