Sperm gets faster and more competitive when around rival males, study on fish finds
- The study revealed that when exposed to competition, sperm performed better
- Researchers studied males in competitive and non-competitive environments
- They found that when exposed to high competition, the male spermatozoa was faster and more competitive
Being in the presence of rival males makes the sperm faster, more competitive and allows it to function better, according to a study on zebrafish.
Researchers examined how having two males in a tank with one female would affect their sperm.
They found that when exposed to high competition, the male spermatozoa was superior to when they are alone with the females, yet showed higher rates of DNA damage.
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The presence of a rival male makes the function and quality of sperm better, according to a study on zebrafish. Researchers examined the effect having two males in a tank with one female would have on their sperm
The study, led by the University of Alicante and the University of Upsala in Sweden, compared two males and one female in a tank for two weeks with one male paired with two females in a tank for two weeks.
Through the application of geometric morphometry, an analysis technique defined as the union between biology and geometry, they isolated variations in the sperm shape and size.
They also analysed their relationship with other cell signalling mechanisms.
The results found that the two male zebrafish in the presence of the rival male were able to produce more efficient sperm while the single male’s was less competent.
The quality of the sperm with the rival male was however affected because the competition meant higher stress levels.
They found that when exposed to high competition, the male spermatozoa was faster and more competitive, yet showed higher rates of DNA damage. The study examined two males and one female
This probably triggered greater production of reactive oxygen species but damaged the DNA chains, affecting both the fertilisation success and the offspring survival.
Lead author of the study Paula Sáez wrote: ‘Although the presence of a rival male increases the competitiveness of spermatozoa, it has negative effects on DNA.
‘This increase could be triggering the damage observed in the DNA chains, affecting both the fertilisation success and the offspring survival, as stated by the UA researcher.’
The presence of a rival male in zebrafish are spermatozoa with a phenotype characterised by smaller heads and an elongation of their intermediate pieces and flagella, as opposed to those exposed to low competition.
In the processing of high rivalry, sperm appeared to be less sensitive to osmotic stress induced by water, according to the researchers.
However, these sperm showed higher rates of DNA damage.
The research was published in the journal Evolutionary Biology.
HOW DO SPERM MOVE?
Sperm are vital in human reproduction and the motility of the male cells is crucial.
In order to help the sperm cells move, they evolved a ‘tail’ which is called a flagellum.
Sperms’ tails play a critical role in their ability to swim and consequently fertilise an egg.
Sperm are vital in human reproduction and the motility of the male cells is crucial. Sperms’ tails play a critical role in their ability to swim and consequently fertilise an egg
Sperm tails consist of around 1,000 building blocks, including structures known as tubulins, which form long tubes.
Attached to these tubes are moving molecules called motorproteins.
These pull and bend sperm tails, enabling them to swim.
The movement of the tail is powered by a mitochondria, the powerhouse of a cell, which produces energy.
