Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Complex sex life of goats could have implications for wildlife management

15.12.2011
A new study of the mating habits of mountain goats reveals the vastly different strategies of males in different populations and could shed light on the unseen impacts of hunting.

A Durham University-led research team found that male chamois (a species of wild goat-antelope) adopt different strategies in different populations in order to succeed in the rut: some put a lot of energy in at a young age, while others wait until they are much older.

Researchers looking at neighbouring populations of chamois in Northern Italy found that males in one population delay their reproductive efforts until an older age when their size and experience allow them to dominate in the rut. They then put increasing effort into breeding until they die.

The study is the first to show clearly that this strategy of 'terminal investment', a pattern of higher reproductive effort in older age, is pursued by males in an animal population. The results, published in the journal PLoS One, show that reproductive strategies in animals are complex and can show surprising variation across neighbouring districts.

It's not clear why there is such variation but the way that these populations are managed through hunting could be a factor, according to the researchers. At present, 32 per cent of the hunting quota is made up of older males, even though these males make up only 23 per cent of the population.

If too many larger, older males are taken out of a population, younger males may be able to muscle in and start breeding. Years of rutting could exhaust these younger males, meaning that they are in poorer condition when they reach old age. If this reasoning is accurate, selectively hunting older males in populations such as this will have the effect of reducing the condition of older males in future.

This suggests that alternative hunting practices – such as hunting males in proportion to their age distribution – might be a better strategy.

Studies of bighorn sheep, a similarly hunted mountain species in America, have also suggested that selective hunting of older males can reduce genetic quality.

Researchers looked at three populations in detail and found that in neighbouring areas surprisingly different strategies prevailed; in one, the terminal investment strategy was dominant, in another, where older males were harvested at a slightly higher rate, the live fast/die younger strategy prevailed.

The group, led by Drs Stephen Willis and Philip Stephens, School of Biological and Biomedical Sciences, Durham University, in collaboration with ecologists at the University of Sassari, Italy, used data from 15,000 hunted male chamois, collected since 1973, to explore their breeding strategies. They looked at the amount of energy males of different ages expended during the annual rut at several sites in the Italian Alps and found unexpected variation across populations.

Co-author Dr Stephen Willis said: "It seems that chamois can have fun in their youth or enjoy their old age but they can't do both. In one valley, males left it until much later to get involved in the rut but, once involved, they showed a pattern of increasing effort, right up to the end of their lives."

The team was able to see how much energy was expended by rutting chamois by looking at how the body masses of males changed throughout the rut period. They were also able to establish the ages of shot individuals from the number of annual growth rings in their horns. The speed at which the animals lose body mass shows how much effort males put in to establishing and patrolling territories, and fighting to defend their harem.

At a site with more hunting and a 'faster' pace of life, the team found that male weight loss during the rut was high, that chamois began rutting at an earlier age and that life-expectancy was lower. By contrast, at a site with a 'slower' pace, lifespans were longer, the weight loss of males was less and males tended to increase the effort they put into reproduction as they got older.

Male chamois barely eat during the rut and use their non-rutting time for resting rather than foraging. They must put on weight prior to the rut in order to succeed and to survive the following winter months.

Co-author of the study, Tom Mason, a Durham University PhD student working on the project, said: "In most species, all males follow one or other of these strategies. It is intriguing that among chamois in different areas, males have different strategies, which might be related to resources, climate or competition."

Dr Philip Stephens added: "These patterns are consistent with two competing theories about how males should optimally allocate effort to reproduction during their lives, so you wouldn't normally expect to see them being displayed so differently by males in neighbouring populations of the same species."

The study is funded by the Natural Environment Research Council (NERC).

Carl Stiansen | EurekAlert!
Further information:
http://www.durham.ac.uk

More articles from Studies and Analyses:

nachricht Statistical method developed at TU Dresden allows the detection of higher order dependencies
07.02.2020 | Technische Universität Dresden

nachricht Novel study underscores microbial individuality
13.12.2019 | Bigelow Laboratory for Ocean Sciences

All articles from Studies and Analyses >>>

The most recent press releases about innovation >>>

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

Im Focus: A step towards controlling spin-dependent petahertz electronics by material defects

The operational speed of semiconductors in various electronic and optoelectronic devices is limited to several gigahertz (a billion oscillations per second). This constrains the upper limit of the operational speed of computing. Now researchers from the Max Planck Institute for the Structure and Dynamics of Matter in Hamburg, Germany, and the Indian Institute of Technology in Bombay have explained how these processes can be sped up through the use of light waves and defected solid materials.

Light waves perform several hundred trillion oscillations per second. Hence, it is natural to envision employing light oscillations to drive the electronic...

Im Focus: Freiburg researcher investigate the origins of surface texture

Most natural and artificial surfaces are rough: metals and even glasses that appear smooth to the naked eye can look like jagged mountain ranges under the microscope. There is currently no uniform theory about the origin of this roughness despite it being observed on all scales, from the atomic to the tectonic. Scientists suspect that the rough surface is formed by irreversible plastic deformation that occurs in many processes of mechanical machining of components such as milling.

Prof. Dr. Lars Pastewka from the Simulation group at the Department of Microsystems Engineering at the University of Freiburg and his team have simulated such...

Im Focus: Skyrmions like it hot: Spin structures are controllable even at high temperatures

Investigation of the temperature dependence of the skyrmion Hall effect reveals further insights into possible new data storage devices

The joint research project of Johannes Gutenberg University Mainz (JGU) and the Massachusetts Institute of Technology (MIT) that had previously demonstrated...

Im Focus: Making the internet more energy efficient through systemic optimization

Researchers at Chalmers University of Technology, Sweden, recently completed a 5-year research project looking at how to make fibre optic communications systems more energy efficient. Among their proposals are smart, error-correcting data chip circuits, which they refined to be 10 times less energy consumptive. The project has yielded several scientific articles, in publications including Nature Communications.

Streaming films and music, scrolling through social media, and using cloud-based storage services are everyday activities now.

Im Focus: New synthesis methods enhance 3D chemical space for drug discovery

After helping develop a new approach for organic synthesis -- carbon-hydrogen functionalization -- scientists at Emory University are now showing how this approach may apply to drug discovery. Nature Catalysis published their most recent work -- a streamlined process for making a three-dimensional scaffold of keen interest to the pharmaceutical industry.

"Our tools open up whole new chemical space for potential drug targets," says Huw Davies, Emory professor of organic chemistry and senior author of the paper.

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

70th Lindau Nobel Laureate Meeting: Around 70 Laureates set to meet with young scientists from approx. 100 countries

12.02.2020 | Event News

11th Advanced Battery Power Conference, March 24-25, 2020 in Münster/Germany

16.01.2020 | Event News

Laser Colloquium Hydrogen LKH2: fast and reliable fuel cell manufacturing

15.01.2020 | Event News

 
Latest News

"Make two out of one" - Division of Artificial Cells

19.02.2020 | Life Sciences

High-Performance Computing Center of the University of Stuttgart Receives new Supercomuter "Hawk"

19.02.2020 | Information Technology

A step towards controlling spin-dependent petahertz electronics by material defects

19.02.2020 | Power and Electrical Engineering

VideoLinks
Science & Research
Overview of more VideoLinks >>>