Stickleback fish are competitive when it comes to fertilizing eggs. Among sticklebacks, fertilization is tricky business because often, other male sticklebacks will try to fertilize the eggs as well.
There are more than seven species of stickleback fish in Europe, North America and other parts of the world. Stickleback fish are often used as freshwater aquarium fish.
Three Spined Stickleback Fish
Three-spined stickleback fish don’t have scales; instead, they have a bony plate of armor like an armadillo. The sticklebacks also have spines which they use to fight off predators.
Image via Wikipedia
In early spring, as mating season begins, the male stickleback changes to become more attractive. His eyes turn bright blue and his belly and throat become a bright red-orange. He also gets silvery scales on his back.
Male sticklebacks builds a nest using available materials during mating season. When each stickleback male is finished, he carries a female fish there to lay their eggs. He then enters the nest to fertilize the eggs.
Male sticklebacks have to ejaculate over the eggs in order to fertilize them. This kind of fertilization is tricky business because often, other males will try to fertilize the eggs as well. Males who ejaculate more raise their chances of being the first to father the baby fish.
Researchers at a Swiss university found that ‘steamy’ films showing flirting fishes induced increased ejaculation in male stickleback fish.
The researchers, who were located at the University of Fribourg, put together two full color films, showing sticklebacks. The first film was a ‘sexy’ film of a male stickleback courting a female. The second was about a male stickleback caring for his brood.
The researchers showed both films to 17 male sticklebacks who had already built nests. After that, females were placed in the Petri dishes in which the male fish had built their nests.
Each fish ejaculated more sperm over the eggs that the females spawned if they had seen the movie of the flirting fish, than if they had seen the film of the male with its brood!
Sticklebacks Stamp from the Faroe Islands-Image via Wikipedia
There are many free science journals online such as Bionotes, which publish research notes and news on different aspects of living things.
Readers, who are interested in free science journals online, which offer information on fisheries and aquaculture, will find the following free science journals helpful:
I. The Open Fish Science Journal, which is an Open Access online journal, focusing on fish science.
II. Naga: The WorldFish Center Quarterly
III. Scientia Marina
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