Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Squirrels winning at outwitting trees' survival strategy

22.12.2006
If you look at evolutionary biology as a big game of “Survivor,” it’s squirrels: one, spruce trees: zero.

In the Dec. 22 edition of Science, Andrew McAdam, an assistant professor of fisheries and wildlife at Michigan State University, outlines how red squirrels have figured out a way around the elaborate ruse trees have used to protect their crops of tasty seeds.

The remarkable part: The squirrels are divining the arrival of bumper crops of spruce cones months before the cones ever materialize and then betting on those crops with the most expensive evolutionary collateral – a second litter of pups.

“We’ve been watching a co-evolutionary arms race where the trees and the squirrels are constantly trying to outwit each other,” McAdam said. “The trees’ strategy to outwit the squirrels has been documented, but now we’ve documented a counter strike by the squirrels.”

The study, funded in part by the National Science Foundation and the Natural Sciences and Engineering Research Council of Canada, allows scientists to track the push and pull of evolution against an unforgiving struggle for survival.

... more about:
»McAdam »masting »pups »red squirrel »squirrel

McAdam, Stan Boutin from the University of Alberta in Edmonton, Canada, and other international collaborators have been studying two different types of squirrels, which share the ‘red squirrel’ name but are only distantly related, in the forests of Canada, Belgium and Italy. The study has been going on for 20 years, with each squirrel carefully tracked.

The red squirrels on this side of the ocean dine almost exclusively on the seeds of spruce cones, which they gnaw off before the seeds ripen. The squirrels are thus a major enemy of the spruce trees. If the squirrels become too successful, their hoarding and gorging on the cones thwarts the trees’ ability to cast seeds and reproduce.

So the battle continues.

Over the years, the trees devised a strategy called masting in which they unpredictably – every few years ­– produce an overabundance of cones. Boutin, the study’s lead author, said it’s called a “swamp and starve” strategy to take predators by surprise, flooding the market with more seeds than the squirrels could harvest. The starve part of the strategy comes from the few cones that are produced in the years between bumper crops.

Swamp and starve is designed to play to the squirrels’ weakness. Squirrels are territorial and need not only food to feed growing pups, but also a place for their offspring to call their own. When there are lots of cones, there is plenty to feed pups, but the catch is that adults also survive well so there aren’t many vacancies for young squirrels searching for a home.

“If you produce lots of pups after the mast, there’s no place for them to go.” McAdam said. “To be successful they need to produce the pups ahead of time.”

What the latest paper shows is that the squirrels are on to the trees’ game, McAdam said. Prior to masting seasons, the squirrels are producing second litters – an act that would be, well, squirrelly in seasons of low food supply.

But a population boom that coincides with a seed boom is brilliant. More food means more places for juvenile squirrels to set up shop.

“What we’ve shown is that the squirrels also are playing an adaptive strategy,” McAdam said. “They’re not just following along; they’re making reproductive decisions that are best for them. This is about how red squirrels make a living in a variable world and how they make reproductive decisions in what seems like unpredictability. And given the currency they use, the stakes are high.”

Boutin speculates that buds the spruce trees put out the summer before cones develop may hold the clues to a masting event. These buds differentiate in the summer; some become tree branches, some develop into cones. The squirrels eat the buds and may detect which destiny they’ll follow thus getting a tip-off to an upcoming masting event.

“I hope this gives people a better appreciation that these squirrels are not just taking what they get,” McAdam said. “Both players – the squirrels and the trees – are following these strategies to try to maximize their fitness.”

Andrew McAdam | EurekAlert!
Further information:
http://www.msu.edu

Further reports about: McAdam masting pups red squirrel squirrel

More articles from Life Sciences:

nachricht Immune Defense Without Collateral Damage
23.01.2017 | Universität Basel

nachricht The interactome of infected neural cells reveals new therapeutic targets for Zika
23.01.2017 | D'Or Institute for Research and Education

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Quantum optical sensor for the first time tested in space – with a laser system from Berlin

For the first time ever, a cloud of ultra-cold atoms has been successfully created in space on board of a sounding rocket. The MAIUS mission demonstrates that quantum optical sensors can be operated even in harsh environments like space – a prerequi-site for finding answers to the most challenging questions of fundamental physics and an important innovation driver for everyday applications.

According to Albert Einstein's Equivalence Principle, all bodies are accelerated at the same rate by the Earth's gravity, regardless of their properties. This...

Im Focus: Traffic jam in empty space

New success for Konstanz physicists in studying the quantum vacuum

An important step towards a completely new experimental access to quantum physics has been made at University of Konstanz. The team of scientists headed by...

Im Focus: How gut bacteria can make us ill

HZI researchers decipher infection mechanisms of Yersinia and immune responses of the host

Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...

Im Focus: Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.

While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...

Im Focus: Studying fundamental particles in materials

Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales

Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Sustainable Water use in Agriculture in Eastern Europe and Central Asia

19.01.2017 | Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

 
Latest News

Tracking movement of immune cells identifies key first steps in inflammatory arthritis

23.01.2017 | Health and Medicine

Electrocatalysis can advance green transition

23.01.2017 | Physics and Astronomy

New technology for mass-production of complex molded composite components

23.01.2017 | Process Engineering

VideoLinks
B2B-VideoLinks
More VideoLinks >>>