Featured Research

from universities, journals, and other organizations

Darkness stifles reproduction of surface-dwelling fish

Date:
June 6, 2011
Source:
North Carolina State University
Summary:
There's a reason to be afraid of the dark. Fish accustomed to living near the light of the water's surface become proverbial "fish out of water" when they move to dark environments like those found in caves, according to a study.

A cave-dwelling Poecilia mexicana, or Atlantic molly.
Credit: Image courtesy of North Carolina State University

There's a reason to be afraid of the dark. Fish accustomed to living near the light of the water's surface become proverbial "fish out of water" when they move to dark environments like those found in caves, according to a study from North Carolina State University.

In research published this week in Biology Letters, a Royal Society scientific journal, NC State post-doctoral researcher Rόdiger Riesch and colleagues found that Atlantic molly females from regular surface streams have a difficult time adjusting to cavelike conditions. Surface female fish had trouble reproducing in the dark conditions, study results show. In addition, many surface-dwelling females introduced to dark conditions -- surprisingly, according to the researchers -- suffered from high incidents of stress-induced bacterial columnaris disease, or "fin rot," which causes patchy lesions on the bodies of the fish.

"Permanent darkness severely hampers reproduction in surface-dwelling females," Riesch says. "But this study also shows that the successful colonization of a subterranean habitat must have been a rare event for Atlantic mollies."

The study was designed to provide an answer to why Atlantic mollies -- their scientific name is Poecilia mexicana -- living close to each other in and near a cave in southern Mexico can evolve in different ways. These population differences are normally attributed to geographic separation -- like mountain ridges or some other physical barrier -- but no physical barrier exists in or around the cave where these Atlantic mollies live.

In the study, the researchers placed some Atlantic mollies in cavelike total darkness while others received a "normal day" of 12 hours of light and 12 hours of darkness.

Most of the cave-dwelling fish of either sex as well as male surface-dwelling fish performed well in both light and darkness. Surface-dwelling females, however, did not breed well or maintain good health in the darkness.

One explanation for the results, Riesch says, has to do with the amount of resources fish have available for reproduction. A fish that has evolved in light has difficulties navigating and finding food in darkness, resulting in reproductive failure.

"Light and dark can completely disrupt life and reproduction for certain fish, and specific key adaptations are necessary to survive in caves," Riesch says. "This study may be one answer to why fish of the same species living side by side can be so different."

The research was funded by the National Science Foundation.


Story Source:

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


Journal Reference:

  1. R. Riesch, M. Plath, I. Schlupp. Speciation in caves: experimental evidence that permanent darkness promotes reproductive isolation. Biology Letters, 2011; DOI: 10.1098/rsbl.2011.0237

Cite This Page:

North Carolina State University. "Darkness stifles reproduction of surface-dwelling fish." ScienceDaily. ScienceDaily, 6 June 2011. <www.sciencedaily.com/releases/2011/05/110510211609.htm>.
North Carolina State University. (2011, June 6). Darkness stifles reproduction of surface-dwelling fish. ScienceDaily. Retrieved August 21, 2014 from www.sciencedaily.com/releases/2011/05/110510211609.htm
North Carolina State University. "Darkness stifles reproduction of surface-dwelling fish." ScienceDaily. www.sciencedaily.com/releases/2011/05/110510211609.htm (accessed August 21, 2014).

Share This




More Earth & Climate News

Thursday, August 21, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

California Drought Stings Honeybees, Beekeepers

California Drought Stings Honeybees, Beekeepers

AP (Aug. 21, 2014) — California's record drought is hurting honey supplies and raising prices for consumers. The lack of rainfall means fewer crops and wildflowers that provide the nectar bees need to make honey. (Aug. 21) Video provided by AP
Powered by NewsLook.com
Thousands Of Species Found In Lake Under Antarctic Ice

Thousands Of Species Found In Lake Under Antarctic Ice

Newsy (Aug. 20, 2014) — A U.S. team found nearly 4,000 species in a subglacial lake that hasn't seen sunlight in millennia, showing life can thrive even under the ice. Video provided by Newsy
Powered by NewsLook.com
Unsustainable Elephant Poaching Killed 100K In 3 Years

Unsustainable Elephant Poaching Killed 100K In 3 Years

Newsy (Aug. 20, 2014) — Poachers have killed 100,000 elephants between 2010 and 2012, as the booming ivory trade takes its toll on the animals in Africa. Video provided by Newsy
Powered by NewsLook.com
Charter Schools Alter Post-Katrina Landscape

Charter Schools Alter Post-Katrina Landscape

AP (Aug. 20, 2014) — Nine years after Hurricane Katrina, charter schools are the new reality of public education in New Orleans. The state of Louisiana took over most of the city's public schools after the killer storm in 2005. (Aug. 20) Video provided by AP
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