MAR 11, 2015 9:20 AM PDT

Love Hurts: What Happens When Snails Stab Their Mates

WRITTEN BY: Greg Cruikshank
Called "love darts," these sharp arrows can reduce fertility and cause early death, a new study says.
The hermaphroditic land snail at left points a sharp love dart at its mate.
They may look harmless, but the snails snacking on your backyard garden boast a sex organ that serves as a sharp, sword-like weapon. Several species of hermaphroditic land snails fire these so-called love darts into each others' bodies while mating. Once a snail manages to shoot the dart, which transfers sperm-boosting secretions, that animal can fertilize the other's eggs.

Made of calcium, these love darts are an essential tool for promiscuous snails, which mate multiple times with different partners to try to fertilize as many snails as they can. However, scientists hadn't known whether these bioweapons were harmful. Now, a new study shows love darts can reduce fertility and shorten life spans in darted snails.

Tough Love

For their experiment, study leader Kazuki Kimura, a biologist at Tohoku University in Japan, and colleagues compared the number of egg clutches with rates of longevity in captive populations of Bradybaena pellucida, a species of land snail native to Japan. The results revealed that a darted snail pays a heavy price for procreation: It will lay fewer eggs and live only three-fourths of a typical snail life span, which is about 60 days, according to the study, published March 10 in Proceedings of the Royal Society B.

It sounds counterintuitive: Why evolve love darts if it will hurt the mother that's carrying your brood? The answer probably comes down to selfish genes-the darts are known to discourage the mother from mating again, which means the darter carries on their own lineage. Joris Koene, a zoologist at VU University Amsterdam who wasn't involved with the study, says it isn't clear whether the loss of libido is caused by a chemical on the darts or is a result of physical trauma, but the latter theory could explain why the snails harm each other.

What's more, the study suggests that damaging the fertility of your partner isn't such a bad idea if you're able to fertilize a lot of their eggs. "It has already been shown that snails can strikingly benefit from an increase in 'short-term' male fertilization success," Kimura says by email. That is, if darts allow a snail to father many more young, a few less isn't a huge deal.

Sexual Arms Race

The study also suggests that these harmful mating habitats are "expected to escalate [the sexual arms race] more drastically," Kimura says. For instance, snails vying for paternity will evolve new and better darts, from simple pointy cones to elaborately bladed harpoons, as Koene noted in a 2005 study. And they will likely also develop a resistance to the darts. For instance, female organs may evolve a resistance to love darts by becoming better at digesting unwanted sperm. Or, evolving a tougher skin-though a long shot for these soft-bodied animals-could provide an anti-dart armor. Because when it comes to hermaphroditic snails, all really is fair in love and war.

(Source: National Geographic)
About the Author
BS
With over 20 years of sales and marketing experience at various Life Science & Biotech Companies, Greg Cruikshank is leveraging his professional and entrepreneurial skills running the internet company Labroots, Inc. Labroots is the leading scientific social networking website, offering top scientific trending news and premier educational virtual events and webinars. Contributing to the advancement of science through content sharing capabilities, Labroots is a powerful advocate in amplifying global networks and communities. Greg has a passion for reptiles, raising various types of snakes and lizards since he was a young boy. This passion has evolved into starting the company Snake Country. At Snake Country, we breed and specialize in Amazon Basin Emerald Tree Boas, and various morphs of Boa Constrictors and Ball Pythons. We have hundreds of snakes in our collection.
You May Also Like
JUL 14, 2022
Chemistry & Physics
The Oldest Traces of Fire Discovered using AI
JUL 14, 2022
The Oldest Traces of Fire Discovered using AI
Scientists have discovered evidence of fire dating back at least 800,000 years. Fire has been essential to human evoluti ...
AUG 05, 2022
Plants & Animals
New survey shows record amounts of coral in Great Barrier Reef
AUG 05, 2022
New survey shows record amounts of coral in Great Barrier Reef
Here’s a little good news for the day: certain areas of the Great Barrier Reef have the highest amount of coral co ...
AUG 17, 2022
Earth & The Environment
The Wreck of The Endurance Has Been Discovered in Antarctica
AUG 17, 2022
The Wreck of The Endurance Has Been Discovered in Antarctica
The expedition of Endurance was one of the legends. It is one of the most harrowing survival stories in naval history.
AUG 26, 2022
Plants & Animals
Ultra-processed Foods Have a Significant Impact on Mental Health
AUG 26, 2022
Ultra-processed Foods Have a Significant Impact on Mental Health
Processed foods are a ubiquitous part of Western diets. The vast majority of packaged foods in the U.S. are processed. I ...
SEP 11, 2022
Technology
Walking and Slithering Share Common Characteristics
SEP 11, 2022
Walking and Slithering Share Common Characteristics
In a recent study published in the Proceedings of the National Academy of Sciences, a team of researchers led by the Uni ...
SEP 15, 2022
Infographics
The Domestication of Dogs
SEP 15, 2022
The Domestication of Dogs
Modern dogs, which have descended from a now-extinct lineage of wolves, are often called “man’s best friend& ...
Loading Comments...