Snail's 'love dart' works like a syringe – a first, study says

Image of love dart
This is a scanning electron micrograph of the love dart of Everettia corrugata corrugata. A. The side view illustrates the row of perforations on one of the two sides. B. The cross section shows the channels inside the shaft of the dart that connect to the perforations along the dart’s flank.

When certain hermaphrodite snails — that is they are male and female at the same time — mate, they stab each other with so-called love darts. Now, for the first time, scientists have discovered a snail species with a love dart that works like an injection needle.

The syringe-like dart delivers a "gland product" to the partner snail "via channels within the dart and comes out through the holes that are present on the side of the dart," Joris Koene, an ecologist at Vrije University in Amsterdam, explained to NBC News in an email.

Other snails' love darts carry a gland substance on their outside, he added, "so this is indeed the first example of a (rather complicated) injection needle."

What the newly discovered gland product of the Malaysian snail does to the mate is, for now, unknown, Koene said, though it may cause the female reproductive system to store more sperm for fertilization of eggs as a gland product does in the better studied brown garden snail.

Given the attachment of the syringe-like dart to the Malaysian snail, it "is almost certainly reused on different partners during different matings," Koene added.

In addition to highlighting the biological diversity of love darts, the study published online July 24 in the journal PLoS One "might further inspire the field of biomimicry" for a new class injection needles at the doctor's office, the team concludes in the paper.

John Roach is a contributing writer for NBC News. To learn more about him, visit his website.