Navigation Links
Dispersal patterns key to invasive species' success
Date:1/20/2014

DURHAM, N.C. -- In 1859 an Australian farmer named Thomas Austin released 24 grey rabbits from Europe into the wild because it "could do little harm and might provide a touch of home, in addition to a spot of hunting."

By the end of the century, the rabbits had begun to overrun native ecosystems, reaching nationwide numbers of 600 million by 1950. They were propagating under a principle known as the Allee effect - the observation that larger groups of animals do better at establishing populations in a new environment. Had Austin instead spread the rabbits into many smaller groups across the landscape, things might have turned out differently.

With the help of E. coli and some clever synthetic biology techniques, engineers at Duke University have now tested the limits of the Allee effect. The results have implications for both ecologists dealing with invasive species and medical practitioners fighting infections.

Organisms exhibiting a very strong Allee effect need a certain number of individuals to survive, below which the group will collapse. And while intuition suggests that the more places a species spreads, the more it will thrive, scattering a population too thin by forming too many new colonies could result in the ruin of them all.

The paper appears online in the Proceedings of the National Academy of Sciences the week of Jan. 20.

"From the perspective of an invasive species, it appears to be a good idea to spread out to many different habitats simultaneously," said Lingchong You, associate professor of biomedical engineering at Duke. "If they all survive, the overall growth is much more efficient. But there's a catch because of the Allee effect; there is also a greater chance each population will fall below the critical threshold and every location will fail."

"This can offer insights for people managing invasive species," continued You. "If you limit the number of targets that an invasive species can travel into, you might inadvertently help them thrive."

In the experiment, researchers engineered E. coli to produce a toxin that, left to its own devices, would soon wipe out the entire colony of bacteria. But they also put in a genetic switch that could turn their fortunes around; if enough bacteria were present and the chemicals they use to signal one another reached a certain concentration, they would begin producing an antidote to the toxin. In this way, the bacteria were engineered to have a high Allee effect.

The researchers then tested how well the bacteria did with different dispersal rates. They plucked the bacteria from their original source wells and colonized new ones. Each trial consisted of a different number of target habitats, which affected the density of the new populations.

Just as theory predicted, the greatest success came when the dispersion rate stayed in a happy middle ground. Too few new colonies and the bacteria barely spread; too many and each floundered, including the original source.

The results also have important medical implications, according to You.

"People need to use caution when using antibiotics," said You. "Our bodies' natural microbes are in some ways the first line of defense against invaders, which can often stop an infection from gaining a foothold. But if we recklessly apply antibiotics, we may destroy these defenses and make it easier for just a few foreign bacteria to spread and grow. We may remove their Allee effect."


'/>"/>
Contact: Ken Kingery
ken.kingery@duke.edu
919-660-8414
Duke University
Source:Eurekalert  

Related biology news :

1. Study reveals that animals contribute to seagrass dispersal
2. Measuring dispersal -- how well are soft-sediment invertebrate communities connected on the seafloor?
3. New patterns found in the genetic relationship of 5 major psychiatric disorders
4. Grape consumption associated with healthier eating patterns in US children and adults
5. Climate tug of war disrupting Australian atmospheric circulation patterns
6. Changing ocean temperatures, circulation patterns affecting young Atlantic cod food supply
7. PTSD research: Distinct gene activity patterns from childhood abuse
8. UF fossil bird study on extinction patterns could help todays conservation efforts
9. Do I know you? Memory patterns help us recall the social webs we weave, finds new Cornell study
10. DNA reveals mating patterns of critically endangered sea turtle
11. GW researchers find variation in foot strike patterns in predominantly barefoot runners
Post Your Comments:
*Name:
*Comment:
*Email:
Related Image:
Dispersal patterns key to invasive species' success
(Date:3/22/2017)... , March 21, 2017 Optimove ... used by retailers such as 1-800-Flowers and AdoreMe, ... — Product Recommendations and Replenishment. Using Optimove,s machine learning ... personalized product and replenishment recommendations to their customers ... on predictions of customer intent drawn from a ...
(Date:3/13/2017)... Future of security: Biometric Face Matching software  Continue ... ... to match face pictures against each other or against large databases. The recognition ... ... software for biometric Face Matching on the market. The speed is at 100 ...
(Date:3/6/2017)... MATEO, Calif. , March 6, 2017 /PRNewswire/ ... marketing and sales technology, today announced Predictive Sales ... solution for infusing actionable sales intelligence into Salesforce. ... to automatically enable their sales organizations with deep ... messages that allow for intelligent engagement. Predictive Sales ...
Breaking Biology News(10 mins):
(Date:3/30/2017)... In today,s pre-market research, Stock-Callers.com ... Corp. (NYSE: XON), Progenics Pharmaceuticals Inc. (NASDAQ: PGNX), and ... an article on Barron,s, Credit Suisse upgraded its rating on ... 21 st , 2017. These stocks research reports can be ... ...
(Date:3/29/2017)... Texas, March 29, 2017  Vermillion, Inc. (NASDAQ: ... disease, reported on its results for the fourth ... "2016 marked a pivotal year for ... guideline inclusion, international distribution agreements, major reimbursement progress ... network payer agreements. In addition we cleared our ...
(Date:3/29/2017)... N.J. and PETACH TIKVAH, ...  BrainStorm Cell Therapeutics Inc. (NASDAQ: BCLI), ... technologies for neurodegenerative diseases, announced financial results ... "2016 was a highly successful ... important achievements and significant progress made on ...
(Date:3/29/2017)... ... March 29, 2017 , ... On the heels of the globally recognized ... Travel has announced that it will manage travel services for its 500th clinical trial ... the United States and Europe to offer travel management services specifically for clinical trials ...
Breaking Biology Technology: