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Source: ONE News
Tiny mussel-like creatures living 100 million years ago made
giant sperm longer than their own bodies, proving size has always
mattered for some animals when it comes to sex, scientists
said.
Giant sperm are still around today.
A human sperm, for example, would have to be 40 metres long to measure up against a fruit fly's.
The insect is only a few millimetres in size but can produce 2.5
inch coiled sperm.
Scientists have been unsure if such gigantism is a freakish
one-off.
Now the discovery that ostracodes, an extinct ancient class of
arthropods, displayed the same trait shows that making giant sperm
is a long-standing and evolutionarily successful reproduction
strategy.
"Giant sperm have been produced in at least some species over long
periods of time, even though they come at an extremely high price
for both males and females," said Renate Matzke-Karasz of the
Ludwig Maximilian University in Munich.
In most animals, including humans, reproductive success depends on
males producing a large number of tiny spermatozoa, while females
invest in a few large eggs.
But in some cases where sperm have to compete inside a female's
body, the chance of successful fertilisation can be improved by
increasing the size of the sperm cell.
Matzke-Karasz and colleagues used a new imaging technique known as
"holotomography" to detect organs used for transferring giant sperm
in fossil remains of the ostracodes, which are only one mm
long.
They described their findings in the journal Science.
