Featured Research

from universities, journals, and other organizations

Superconception: European brown hares, while pregnant with one litter, can start a new pregnancy

Date:
September 22, 2010
Source:
Forschungsverbund Berlin e.V. (FVB)
Summary:
European brown hares can develop a second pregnancy whilst the previous litter is not delivered. This superconception increases their reproductive success.

Two Brown Hares. European brown hares can develop a second pregnancy whilst the previous litter is not delivered.
Credit: iStockphoto/Karel Broz

European brown hares can develop a second pregnancy whilst the previous litter is not delivered. This superconception increases their reproductive success.

Scientists of the Leibniz Institute for Zoo and Wildlife Research (IZW) in Berlin, Germany, elucidated the phenomenon of "superfetation (superconception)," a second pregnancy whilst already pregnant, using high resolution ultrasonography in female living European brown hares (Lepus europaeus). The results are now published in the latest issue of the scientific journal Nature Communications.

Applying an experimental approach within a captive colony of hares, scientist found that ovaries of hares close to parturition had active corpora lutea from an initial pregnancy plus a more recent, less developed set of corpora lutea indicating a second, simultaneous pregnancy. Corpora lutea develop after an ovulation and produce progesterone, the pregnancy hormone. The ovulation in female hares does not occur spontaneously and regularly but only after copulation with a male hare.

Copulation in late pregnancy is initiated by the female hare. If copulation occurred after the 37th day of pregnancy it was unclear whether semen could cross the uterus in late pregnany or was stored from a previous insemination in the reproductive tract. "Using different males as fathers, genetic paternity tests revealed that semen must have passed the uterus with the previous fully developed litter inside," says Dr. Kathleen Roellig, scientist and veterinarian at the IZW. The European brown hares were fertilized during late pregnancy and developed a second pregnancy around four days before delivery. The embryos develop in the oviduct and migrate to the uterus. After parturition of the previous litter the new embryos were already four days old and the next implantation could occur immediately. Hence, the interval between two successive litters was 38 days instead of at least 42 days which is the normal duration of a pregnancy in hares."

"New in our study was the collection of data using the latest examination technique in living females. Therefore we examined female hares repeatedly using high-resolution ultrasound to make the "invisible visible" ," says Roellig. With this method, criteria could be developed for the first time to demonstrate superfetation in living individuals. The findings suggest that using this reproductive mechanism of superfetation, female hares can deliver up to one third more offspring per reproductive season. "Therefore we think that superfetation might be an evolutionary adaptation to increase the reproductive success," says Roellig.

Since the times of Aristotle the European brown hare was assumed to have the mechanism of superfetation. However, findings were not conclusive and the functional mechanisms of superfetation were not clear. Shortened intervals between successive parturitions have previously been observed in several captive populations, thus fertilization before delivery was assumed to occur. The systematic examination coupled with an experimental approach applied to their captive population enabled the researchers of the IZW to elucidate the phenomenon of superfetation in the European brown hare.


Story Source:

The above story is based on materials provided by Forschungsverbund Berlin e.V. (FVB). Note: Materials may be edited for content and length.


Journal Reference:

  1. Kathleen Roellig, Frank Goeritz, Joerns Fickel, Robert Hermes, Heribert Hofer, Thomas B. Hildebrandt. Superconception in mammalian pregnancy can be detected and increases reproductive output per breeding season. Nature Communications, 2010; 1 (6): 1 DOI: 10.1038/ncomms1079

Cite This Page:

Forschungsverbund Berlin e.V. (FVB). "Superconception: European brown hares, while pregnant with one litter, can start a new pregnancy." ScienceDaily. ScienceDaily, 22 September 2010. <www.sciencedaily.com/releases/2010/09/100921174210.htm>.
Forschungsverbund Berlin e.V. (FVB). (2010, September 22). Superconception: European brown hares, while pregnant with one litter, can start a new pregnancy. ScienceDaily. Retrieved July 30, 2014 from www.sciencedaily.com/releases/2010/09/100921174210.htm
Forschungsverbund Berlin e.V. (FVB). "Superconception: European brown hares, while pregnant with one litter, can start a new pregnancy." ScienceDaily. www.sciencedaily.com/releases/2010/09/100921174210.htm (accessed July 30, 2014).

Share This




More Plants & Animals News

Wednesday, July 30, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Concern Grows Over Worsening Ebola Crisis

Concern Grows Over Worsening Ebola Crisis

AFP (July 30, 2014) Pan-African airline ASKY has suspended all flights to and from the capitals of Liberia and Sierra Leone amid the worsening Ebola health crisis, which has so far caused 672 deaths in Guinea, Liberia and Sierra Leone. Duration: 00:43 Video provided by AFP
Powered by NewsLook.com
Raw: Otters Enjoy Water Slides at Japan Zoo

Raw: Otters Enjoy Water Slides at Japan Zoo

AP (July 30, 2014) River otters were hitting the water slides to beat the summer heatwave on Wednesday at Ichikawa City's Zoological and Botanical Garden. (July 30) Video provided by AP
Powered by NewsLook.com
In Virginia, the Rise of a New Space Coast

In Virginia, the Rise of a New Space Coast

AP (July 30, 2014) Every summer, tourists make the pilgrimage to Chincoteague Island, Va. to see wild ponies cross the Assateague Channel. But, it's the rockets sending to supplies to the International Space Station that are making this a year-round destination. (July 30) Video provided by AP
Powered by NewsLook.com
Rodents Rampant in Gardens Around Louvre

Rodents Rampant in Gardens Around Louvre

AP (July 29, 2014) Food scraps and other items left on the grounds by picnickers brings unwelcome visitors to the grounds of the world famous and popular Louvre Museum in Paris. (July 29) 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