They only spawn at full moon, the girls literally 'light up' at the prospect of finding a mate, and dozens of tourists hang out in boats to watch them at it. Welcome to the weird and wonderful world of Bermuda's famous fireworms.

Once a month during the summer season the Bermuda Underwater Exploration Institute (BUEI) hosts a cruise to watch the female fireworm emit her strikingly beautiful green light as she whirls frantically in circles to attract a mate.

She releases her glowing eggs when he darts up and reaches the 'bull's eye' of her circle, producing a bright flash himself as he releases his sperm.

That's if everything goes to plan. However on the night I headed out to watch the worms, the males ? less common than the females and often late for the beginning of the spawning burst ? were nowhere to be seen.

The ladies were left spinning forlornly but spectacularly on their own without a partner in sight.

Having let out a chorus of "ooh" and "ah" reminiscent of kids at a fireworks display when the fireworms first put in an appearance, the sympathies of those on the boat quickly focused on this unfortunate turn of events for the frustrated worms.

"Let's play a bit of Marvin Gaye or some Barry White?" suggested one wag.

Another tourist ? having carefully waited until her husband was out of earshot, mused: "They get all dolled up and then no men turn up. Don't you just hate it when that happens?"

It must have been an unlucky night for them ? according to scientific studies, it's a common occurrence for several males to be attracted to a single female, which results in them all rotating in a tight circle as the males discharge their sperm into the water.

Spawning begins at full moon and reaches a peak three days afterwards.

The females appear at the water's surface between 51 and 63 minutes after sunset in a display that only lasts a few minutes.

The mesmerising fireworms are actually marine relatives of the familiar earthworm and their Latin name ? ? translates as 'the toothed and necklaced worm'.

The creatures are only ten to 20 millimetres long and inhabit the sandy bottoms of Bermuda's bays and inlets, with Ferry Reach being one of the best spots to see them, according to seasoned worm watchers.

The males are smaller than the females but have larger eyes, in keeping with their sensitivity to the light given off by the females. According to a research paper published by Bermuda Biological Station for Research scientists in 1961 they are "equally stimulated by the beam from a flashlight".

When one unfortunate worm suffered the indignity of being scooped up in a fishing net and plonked in a jar for us to gaze at she looked very plain and ugly starved of her happy mating-fuelled glow.

Released back into the water, she quickly perked up and resumed her dance of light.

The green glow emitted by the fireworms ? found throughout the tropical western Atlantic ? is the product of bioluminescence, a light produced by a chemical reaction in a living organism.

They only produce their dance of light during mating activities ? although some scientists have observed that they also glow in response to being startled.

Little is known about what exactly triggers the mating ritual which can be predicted with extraordinary accuracy and much mystery still surrounds these fascinating creatures.

It's even been suggested that they were responsible for the strange patches of light seen by Christopher Columbus four hours before he first made landfall in America.

Whether or not it's true that these creatures had a role in this 500-year-old mystery, according to BUEI volunteer Judie Clee, the story of the fireworms itself is an age-old one: "It's all about sex, food, and hiding from your predators."

"People love being out there on the cruise and seeing something special," she added. "There's such anticipation as everyone peers over the side of the boat and watches how much light is emitted by such a small creature. Mother Nature is amazing."