Sex: shipworms with larger appendages have an advantage when training with rival partners, study finds

When fighting and sparring with your sexual rivals, size does matter after all, at least if you’re a shipworm, according to one study.

Portsmouth experts have captured this “sexual frenzy” on film for the first time, recording the worm-like creatures involved in so-called “pseudo-copulation.”

This is when groups of neighboring worms inseminate each other, during which time they often fight opponents and try to get rid of their rivals’ sperm.

In this sexual combat, the worm with the largest appendix usually prevails.

Shipworms, a naked freshwater clam, are common in the world’s oceans, where they use their tiny vestigial shells as drills to drill burrows in wood.

In this way, they cause billions of pounds of damage each year by damaging wooden ships, piers, piers, and sea defenses.

Better understanding how they reproduce, the team said, could help us develop new ways to manage marine pests.

Scroll down to see the video

When fighting and sparring with your sexual rivals, size does matter, after all, at least if you’re a shipworm, according to one study. In the photo, shipworms fighting

“When we first noticed that these animals were reproducing in the aquarium, we couldn’t believe what we were seeing,” said paper author and marine biologist Reuben Shipway of the University of Portsmouth.

‘They were using their siphons to fight and inseminate each other and exchange sperm. As far as we know, this free and fair fight has not been reported before. ‘

Each shipworm has two long siphons: one for taking in water and the other for expelling body waste. They are usually the only parts of the worm that protrude from the wood in which they burrow.

‘Most of the time, [shipworms are] it’s not very interesting to watch, ”Dr. Shipway said.

However, he explained: “One day I was in the aquarium and I noticed that there was a thick column of creamy liquid in the tank, which I knew had to be eggs and sperm.”

“When I got a little closer, I realized that the siphons of these animals were going crazy and I was witnessing a sexual frenzy, and I decided to film it.”

“ Periodically I would go and come back a few hours later and they were still at it. ”

Portsmouth experts have captured the 'sexual frenzy' on film for the first time, recording the worm-like creatures (pictured) participating in so-called 'pseudo-copulation'

Portsmouth experts have captured the ‘sexual frenzy’ on film for the first time, recording the worm-like creatures (pictured) participating in so-called ‘pseudo-copulation’

Pseudocopulation is when groups of neighboring worms inseminate each other, during which they often fight their opponents and try to get rid of their rivals' sperm.  In this sexual combat, the worm with the largest appendix usually prevails.  In the photo, a ship worm

Pseudocopulation is when groups of neighboring worms inseminate each other, during which they often fight their opponents and try to get rid of their rivals’ sperm. In this sexual combat, the worm with the largest appendix usually prevails. In the photo, a ship worm

In the footage recorded by Dr. Shipway, several shipworms can be seen mating with each other, some receiving sperm and one end while simultaneously planting their own sperm into a different shipworm at the same time.

Some were seen to extract sperm from themselves, while others wrestled with rivals and even extracted their rival’s sperm from their target partner.

The researchers believe that shipworms that grow rapidly to a larger size have a competitive advantage because they end up with longer siphons, allowing them to better defend themselves against rivals and fertilize their neighbors.

“When we first noticed these animals reproducing in the aquarium, we couldn’t believe what we were seeing,” said paper author and marine biologist Reuben Shipway of the University of Portsmouth. ‘They were using their siphons to fight and inseminate each other and exchange sperm. As far as we know, this free and fair fight has not been reported before. ‘

Each shipworm has two long siphons, one for taking in water and the other for expelling body waste.  They are usually the only parts of the worm that protrude from the wood in which they burrow, as shown in the image.

Each shipworm has two long siphons: one for taking in water and the other for expelling body waste. These are usually the only parts of the worm that protrude from the wood in which they burrow, as shown in the image.

“While pseudo-copulation has been known to occur in shipworms for some time, this may be the first time the behavior has been captured on film and the first time its apparent competitive nature has been revealed,” explained Dr. Shipway.

“ It is a rare and sophisticated form of reproductive behavior, with fights between rival partners, bringing potential partners closer and further away from rivals, and even going as far as to include extracting a rival’s sperm from a siphon so that it floats. ”

“Shipworms have developed an amazing diversity of reproductive strategies,” he added.

“ Some simply spawn their eggs and sperm in the water, some recruit a harem of dwarf males to mate with, and we now know that they compete to directly inseminate each other using their siphons. ”

“Shipworms are one of the few animals that can digest wood; turning it into tasty clam and larval tissue, “added article author Nancy Treneman of the Oregon Institute of Marine Biology.

“Humanity’s battle for millennia with these fragile animals to limit their voracious appetite for our wooden ships, docks and levees has met with limited success.”

“Studying their reproduction increases our understanding of their place in the ocean’s web of life and how we might one day prevent ships from being eaten.”

The full findings of the study were published in the journal Biology Letters.

In the footage recorded by Dr. Shipway, multiple shipworms can be seen mating with each other, some receiving sperm and one end while simultaneously planting their own sperm into a different shipworm at the same time.

In footage recorded by Dr. Shipway, several shipworms can be seen mating with each other, some receiving sperm and one butt at the same time planting their own sperm into a different shipworm at the same time.

Shipworms, a naked freshwater clam (pictured), are common in the world's oceans, where they use their tiny vestigial shells as drills to drill burrows in wood, as shown in the image.

Shipworms, a naked freshwater clam (pictured), are common in the world’s oceans, where they use their tiny vestigial shells as drills to drill burrows in wood, as shown in the image.

Source