Featured Research

from universities, journals, and other organizations

Male snails babysit for other dads: Family secrets of marine whelk Solenosteira macrospira

Date:
August 28, 2012
Source:
University of California - Davis
Summary:
Pity the male of the marine whelk, Solenosteira macrospira. He does all the work of raising the young, from egg-laying to hatching -- even though few of the baby snails are his own. Throw in extensive promiscuity and sibling cannibalism, and the species has one of the most extreme life histories in the animal kingdom.

Pity the male of the marine whelk, Solenosteira macrospira. He does all the work of raising the young, from egg-laying to hatching — even though few of the baby snails are his own.
Credit: Image courtesy of University of California - Davis

Pity the male of the marine whelk, Solenosteira macrospira. He does all the work of raising the young, from egg-laying to hatching -- even though few of the baby snails are his own.

Related Articles


The surprising new finding by researchers at the University of California, Davis, puts S. macrospira in a small club of reproductive outliers characterized by male-only child care. Throw in extensive promiscuity and sibling cannibalism, and the species has one of the most extreme life histories in the animal kingdom.

The family secrets of the snail, which lives in tidal mudflats off Baja California, are reported online in a study in the journal Ecology Letters.

In the study, UC Davis researchers report that, on average, only one in four of the hundreds of eggs that a male S. macrospira carries around on his back belong to him. Some carry the offspring of as many as 25 other males.

Such extreme cases provide the raw material on which natural selection can work and shed light on more "mainstream" species, said study author Rick Grosberg, a professor of evolution and ecology at UC Davis.

"It opens our eyes to viewing other kinds of behavior not as weird or harmful but as normal," he said.

The snails were first described in an amateur shell-collectors newsletter, The Festivus, in 1973. Grosberg started studying the animals in 1994, when he brought some back from a collecting trip and realized that only male snails had egg capsules on their shells.

When the snails mate, the female glues capsules containing hundreds of eggs each to the male's shell.

The male's shell likely acts as a substitute rock, since the snails' habitat offers few surfaces on which to glue eggs, said co-author Stephanie Kamel, a postdoctoral researcher in Grosberg's lab.

Moving in and out with the tide on dad's (or stepdad's) back also protects the egg capsules from the extremes of heat and drying they might face if left on a stationary rock.

A male's shell may become covered in dozens of capsules, each containing up to 250 eggs. As the eggs hatch, a process that takes about a month, some of the baby snails devour the rest of their littermates. Typically only a handful of hatchlings survives the fratricide to emerge from a capsule and crawl away.

Kamel carried out DNA analysis of brood capsules to determine the eggs' parentage. On average, she found that the male snails had sired just 24 percent of the offspring on their backs. Many had sired far less.

"The promiscuity in the female snails is extraordinary," Kamel said, noting that some females mate with as many as a dozen different males.

Why do they do it? Typically in the animal kingdom, females invest more resources in an egg than a male does in a sperm, so mothers have a stronger interest in providing parental care. Males may mate with multiple partners to increase their chances of siring offspring, but typically make less investment in caring for those young. When dads do get involved, it's nearly always because they are assured that all or most of the offspring are their own. Male sea horses, for example, carry developing young in a pouch -- but all are their own genetic offspring.

One explanation could be that caring for the kids just doesn't cost the male snails much. But by tethering individual snails to a post sunk in the sand, Grosberg was able to follow them over time and show that the capsules do impose a significant burden, reflected in weight loss.

It may be that carrying the egg capsules simply represents the best of limited options for the males, Grosberg said, since it's impossible for them to mate without the female attaching an egg capsule to their backs.

Or carrying egg capsules may be a way for a male to show a female that he's good parent material.

"If he wants to get any action, he has to pay the price," Grosberg said.

Grosberg is fascinated by the conflicts that occur between parents, between siblings, and between parents and offspring as they each try to get resources and maximize their success in breeding. You can see these conflicts and rivalries all the way from simple animals to humans, he notes.

"Everything that intrigues me about family life happens in these snails," he said.

At the same time, no animal has gone as far as humans in evolving increasing cooperation between relatives, tribes and larger and larger (and less closely related) groups over time.

"We're good at seeing other forms of reward," Grosberg said.

The work was funded by the National Science Foundation.


Story Source:

The above story is based on materials provided by University of California - Davis. Note: Materials may be edited for content and length.


Journal Reference:

  1. Stephanie J. Kamel, Richard K. Grosberg. Exclusive male care despite extreme female promiscuity and low paternity in a marine snail. Ecology Letters, 2012; DOI: 10.1111/j.1461-0248.2012.01841.x

Cite This Page:

University of California - Davis. "Male snails babysit for other dads: Family secrets of marine whelk Solenosteira macrospira." ScienceDaily. ScienceDaily, 28 August 2012. <www.sciencedaily.com/releases/2012/08/120828163036.htm>.
University of California - Davis. (2012, August 28). Male snails babysit for other dads: Family secrets of marine whelk Solenosteira macrospira. ScienceDaily. Retrieved December 22, 2014 from www.sciencedaily.com/releases/2012/08/120828163036.htm
University of California - Davis. "Male snails babysit for other dads: Family secrets of marine whelk Solenosteira macrospira." ScienceDaily. www.sciencedaily.com/releases/2012/08/120828163036.htm (accessed December 22, 2014).

Share This


More From ScienceDaily



More Plants & Animals News

Monday, December 22, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Christmas Kissing Good for Health

Christmas Kissing Good for Health

Reuters - Innovations Video Online (Dec. 22, 2014) Scientists in Amsterdam say couples transfer tens of millions of microbes when they kiss, encouraging healthy exposure to bacteria. Suzannah Butcher reports. Video provided by Reuters
Powered by NewsLook.com
Brain-Dwelling Tapeworm Reveals Genetic Secrets

Brain-Dwelling Tapeworm Reveals Genetic Secrets

Reuters - Innovations Video Online (Dec. 22, 2014) Cambridge scientists have unravelled the genetic code of a rare tapeworm that lived inside a patient's brain for at least four year. Researchers hope it will present new opportunities to diagnose and treat this invasive parasite. Matthew Stock reports. Video provided by Reuters
Powered by NewsLook.com
Earthworms Provide Cancer-Fighting Bacteria

Earthworms Provide Cancer-Fighting Bacteria

Reuters - Innovations Video Online (Dec. 21, 2014) Polish scientists isolate bacteria from earthworm intestines which they say may be used in antibiotics and cancer treatments. Suzannah Butcher reports. Video provided by Reuters
Powered by NewsLook.com
Existing Chemical Compounds Could Revive Failing Antibiotics, Says Danish Scientist

Existing Chemical Compounds Could Revive Failing Antibiotics, Says Danish Scientist

Reuters - Innovations Video Online (Dec. 21, 2014) A team of scientists led by Danish chemist Jorn Christensen says they have isolated two chemical compounds within an existing antipsychotic medication that could be used to help a range of failing antibiotics work against killer bacterial infections, such as Tuberculosis. Jim Drury went to meet him. 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