Featured Research

from universities, journals, and other organizations

Preventing home invasions means fighting side-by-side for coral-dwelling crabs and shrimp

Date:
March 30, 2012
Source:
Smithsonian
Summary:
As any comic book lover knows, when superheroes band together the bad guys fall harder. The strength that comes in numbers is greater than the sum of its parts. The same holds true, researchers have recently learned, when different species of crabs and snapping shrimp in the central Pacific band together to defend their coral homes from hungry seastars.

Alpheus lottini, a snapping shrimp.
Credit: Photo courtesy of Seabird McKeon

As any comic book lover knows, when superheroes band together the bad guys fall harder. The strength that comes in numbers is greater than the sum of its parts.

The same holds true, researchers have recently learned, when different species of crabs (genus Trapezia) and snapping shrimp (Alepheus lottini) in the central Pacific band together to defend their coral homes from hungry seastars. In these frequent conflicts "one-plus-one doesn't always equal two, sometime it is more," explains Seabird McKeon, a marine biologist at the National Museum of Natural History's Smithsonian Marine Station in Fort Pierce, Fla. The crustaceans are much more effective when they fight together than when they fight alone, a process McKeon calls the Multiple Defender Effect. "It is a clear example of synergy, and one that underscores the importance of biodiversity in the ocean."

Even in a comic book one would be hard pressed to find an enemy more bizarre than the "cushion" seastar (Culcita novaeguineae), an animal used by McKeon in recent laboratory experiments with living corals (genus Pocillopora) and their defenders. To consume a coral, the seastar pushes its stomach outside its body and lays it over the coral like a cushion. It then hugs the coral close and "eats," letting stomach acids and digestive juices do their work.

The stationary coral is defenseless, yet the tiny crustaceans that live among its branches come to its aid, snipping and prodding an intruding seastar with their claws. "The coral itself is like a cauliflower head, a main central stem and lots of little branches," McKeon explains. "Crabs gain protection from fish by living inside the coral structure."

Once a mating pair of crabs takes-up residence on a coral head they do not tolerate the presence of other crabs of their same species. Crabs of other species however are ignored, as are snapping shrimp. As a result, some coral heads may have as many as five different species of defensive crustaceans living on them, all pairs of different species.

In repeated experiments McKeon and colleagues measured the effectiveness of a single crab pair in preventing a seastar from eating their home coral. He found that one pair of crabs reduced the volume of coral eaten by about 19 percent, compared to a coral with no defenders. Two pairs of crustaceans working together, however, were able to reduce the volume of coral eaten by as much as 65 percent -- the multiple defender effect.

The take-home lesson here, McKeon says, "is these crabs don't allow others of their same species on their coral, yet the synergy of different pairs fighting together is critical to the defense of the coral. The multiple defender effect is an important new angle on why we must conserve biodiversity in the ocean."


Story Source:

The above story is based on materials provided by Smithsonian. Note: Materials may be edited for content and length.


Journal Reference:

  1. C. Seabird McKeon, Adrian C. Stier, Shelby E. McIlroy, Benjamin M. Bolker. Multiple defender effects: synergistic coral defense by mutualist crustaceans. Oecologia, 2012; DOI: 10.1007/s00442-012-2275-2

Cite This Page:

Smithsonian. "Preventing home invasions means fighting side-by-side for coral-dwelling crabs and shrimp." ScienceDaily. ScienceDaily, 30 March 2012. <www.sciencedaily.com/releases/2012/03/120330164856.htm>.
Smithsonian. (2012, March 30). Preventing home invasions means fighting side-by-side for coral-dwelling crabs and shrimp. ScienceDaily. Retrieved April 20, 2014 from www.sciencedaily.com/releases/2012/03/120330164856.htm
Smithsonian. "Preventing home invasions means fighting side-by-side for coral-dwelling crabs and shrimp." ScienceDaily. www.sciencedaily.com/releases/2012/03/120330164856.htm (accessed April 20, 2014).

Share This



More Earth & Climate News

Sunday, April 20, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Drought Concerns May Hurt Lake Tourism

Drought Concerns May Hurt Lake Tourism

AP (Apr. 18, 2014) Operators of recreational businesses on western reservoirs worry that ongoing drought concerns will keep boaters and other visitors from flocking to the popular summer attractions. (April 18) Video provided by AP
Powered by NewsLook.com
Man Claims He Found Loch Ness Monster With... Apple Maps?

Man Claims He Found Loch Ness Monster With... Apple Maps?

Newsy (Apr. 18, 2014) Andy Dixon showed the Daily Mail a screenshot of what he believes to be the mythical beast swimming just below the lake's surface. Video provided by Newsy
Powered by NewsLook.com
First Ever 'Female Penis' Discovered In Animal Kingdom

First Ever 'Female Penis' Discovered In Animal Kingdom

Newsy (Apr. 18, 2014) Not only are these newly discovered bugs' sex organs reversed, but they also mate for up to 70 hours. Video provided by Newsy
Powered by NewsLook.com
Ark. Man Finds 6-Carat Diamond At State Park

Ark. Man Finds 6-Carat Diamond At State Park

Newsy (Apr. 18, 2014) An Arkansas man has found a nearly 6.2-carat diamond, which he dubbed "The Limitless Diamond," at the Crater of Diamonds State Park. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins