Navigation Links
Living on islands makes animals tamer
Date:1/10/2014

RIVERSIDE, Calif. Most of us have seen pictures and probably YouTube videos of "tame" animals on the Galapagos Islands, the biological paradise that was Charles Darwin's major source of inspiration as he observed nature and gradually developed his ideas about the importance of natural selection as a mechanism by which populations of organisms would change evolve genetically across generations, eventually becoming better and better suited to life in their current conditions.

A corollary of Darwin's revolutionary idea was that organisms would also evolve to lose structures, functions, and behaviors they no longer needed when environmental circumstances changed. He noted that island animals often acted tame, and presumed that they had evolved to be so after coming to inhabit islands that lacked most predators.

But more than 150 years later that almost casual observation remained to come under scientific scrutiny. Now, a team of researchers from the University of California, Riverside, Indiana University Purdue University Fort Wayne and George Washington University have published a study showing that island lizards are indeed "tame" as compared with their mainland relatives. The researchers were able to approach island lizards more closely than they could approach mainland lizards.

"Our study confirms Darwin's observations and numerous anecdotal reports of island tameness," said Theodore Garland, a professor of biology at UC Riverside and one of the paper's coauthors. "His insights have once again proven to be correct, and remain an important source of inspiration for present-day biologists."

Study results appear online this week in the Proceedings of the Royal Society B. They will appear in the journal in print on Feb. 22.

The researchers conducted analyses of relationships of flight initiation distance (the predatorprey distance when the prey starts to flee) to distance to mainland, island area, and occupation of an island for 66 lizard species, taking into account differences in prey size and predator approach speed. They analyzed island and mainland lizard species from five continents and islands in the Atlantic and Pacific Oceans and the Caribbean and Mediterranean Seas.

Their results showed that island tameness exists and that flight initiation distance decreases as distance from mainland increases. In other words, island lizards were more accessible the farther the islands were from the mainland.

"The suggestion by Darwin and others that prey on oceanic islands have diminished escape behavior is supported for lizards, which are distributed widely on both continents and islands," Garland said.

He explained that escape responses are reduced on remote islands, because predators are scarce or absent there, and natural selection under reduced predation favors prey that do not waste time and energy developing and performing needless escape.

The research team also found that prey size is an important factor that affects escape behavior.

"When prey are very small relative to predators, predators do not attack isolated individual prey," Garland said. "This results in the absence of fleeing or very short flight initiation distance."

The researchers found no conclusive evidence showing that flight initiation distance is related to island area. They found, however, that predator approach speed is an important factor in lizards.

"It is possible that other factors favor island tameness. For example, if food is scarce on islands, the cost of leaving food to flee would favor shortened flight initiation distance," Garland said.


'/>"/>

Contact: Iqbal Pittalwala
iqbal@ucr.edu
951-827-6050
University of California - Riverside
Source:Eurekalert  

Related biology news :

1. New evidence suggests Neanderthals organized their living spaces
2. A living desert underground
3. Scientists capture redox moments in living cells
4. How living cells solved a needle in a haystack problem to produce electrical signals
5. South African living stone plant adapts to extreme conditions in new ways
6. Clean living is a luxury wild animals cant afford, study suggests
7. Education protects women from the obesity associated with urban living
8. Researchers perform DNA computation in living cells
9. Mimicking living cells: Synthesizing ribosomes
10. Living biofilters could reduce greenhouse gas emissions
11. Living fossils? Actually, sturgeon are evolutionary speedsters
Post Your Comments:
*Name:
*Comment:
*Email:
Related Image:
Living on islands makes animals tamer
(Date:5/12/2016)... WearablesResearch.com , a brand of Troubadour Research & ... Q1 wave of its quarterly wearables survey. A particular ... a program where they would receive discounts for sharing ... "We were surprised to see that so many ... CEO of Troubadour Research, "primarily because there are segments ...
(Date:4/28/2016)... 28, 2016 First quarter 2016:   ... compared with the first quarter of 2015 The gross ... M (loss: 18.8) and the operating margin was 40% (-13) ... Cash flow from operations was SEK 249.9 M (21.2) , ... is unchanged, SEK 7,000-8,500 M. The operating margin for ...
(Date:4/15/2016)... CHICAGO , April 15, 2016  A ... companies make more accurate underwriting decisions in a ... offering timely, competitively priced and high-value life insurance ... health screenings. With Force Diagnostics, rapid ... and lifestyle data readings (blood pressure, weight, pulse, ...
Breaking Biology News(10 mins):
(Date:6/27/2016)... (PRWEB) , ... June 27, 2016 , ... Parallel ... clinical trials, announced today the Clinical Reach Virtual Patient Encounter CONSULT module ... circle with the physician and clinical trial team. , Using the CONSULT module, patients ...
(Date:6/24/2016)... -- Regular discussions on a range of subjects including policies, debt ... said Poloz. Speaking at a lecture to the ... pointed to the country,s inflation target, which is set by ... "In certain areas there needs to ... goals, why not sit down and address strategy together?" ...
(Date:6/23/2016)... ... 23, 2016 , ... UAS LifeSciences, one of the leading ... UP4™ Probiotics, into Target stores nationwide. The company, which has been manufacturing high ... its list of well-respected retailers. This list includes such fine stores as Whole ...
(Date:6/23/2016)... , ... June 23, 2016 , ... ... YM (Yeast and Mold) microbial test has received AOAC Research Institute approval 061601. ... microbial tests introduced last year,” stated Bob Salter, Vice President of Regulatory and ...
Breaking Biology Technology: