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.

Related Articles


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 November 25, 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 November 25, 2014).

Share This


More From ScienceDaily



More Earth & Climate News

Tuesday, November 25, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Antarctic Sea Ice Mystery Thickens... Literally

Antarctic Sea Ice Mystery Thickens... Literally

Newsy (Nov. 25, 2014) — Antarctic sea ice isn't only expanding, it's thicker than previously thought, and scientists aren't sure exactly why. Video provided by Newsy
Powered by NewsLook.com
3D Map of Antarctic Sea Ice to Shed Light on Climate Change

3D Map of Antarctic Sea Ice to Shed Light on Climate Change

Reuters - Innovations Video Online (Nov. 24, 2014) — A multinational group of scientists have released the first ever detailed, high-resolution 3-D maps of Antarctic sea ice. Using an underwater robot equipped with sonar, the researchers mapped the underside of a massive area of sea ice to gauge the impact of climate change. Ben Gruber reports. Video provided by Reuters
Powered by NewsLook.com
Car Park Solution for Flexible Green Energy

Car Park Solution for Flexible Green Energy

Reuters - Innovations Video Online (Nov. 24, 2014) — A British solar power start-up says that by covering millions of existing car park spaces around the UK with flexible solar panels, the country's power problems could be solved. Suzannah Butcher reports. Video provided by Reuters
Powered by NewsLook.com
Yellow-Spotted Turtles Rescued from Trafficking

Yellow-Spotted Turtles Rescued from Trafficking

Reuters - Light News Video Online (Nov. 24, 2014) — Hundreds of Amazon River turtles released into the wild in Peru. Sharon Reich reports. Video provided by Reuters
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:

Strange & Offbeat Stories

 

Plants & Animals

Earth & Climate

Fossils & Ruins

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