We finally know how tardigrades reproduce

1 min read

ANIMALS

WORDS ELISE POORE AND TIA GHOSE

For the first time, scientists have figured out how tardigrades, some of the toughest creatures on the planet, mate. These tiny, hardy critters have few obvious differences between males and females, which made it unlikely that they found mates by sight alone. A recent study suggests that females may release a chemical cue that lures the males. The males strongly responded, moving towards the females in water environments. However, females don’t seem to have the same compulsion.

Tardigrades, also known as water bears, can tolerate extreme conditions. For example, they can survive a combined exposure to the vacuum of space, cosmic radiation and ultraviolet radiation. Unlike some animals, male and female tardigrades are hard to distinguish. There are size differences, but no obvious secondary traits. As a result, it wasn’t clear how most of the 1,300 tardigrade species found mates. One theory is that these microscopic animals release a chemical signal to find a mate. To test that theory, Justine Chartrain, a doctoral researcher at the University of Jyväskylä in Finland, and colleagues performed a series of experiments with the species Macrobiotus polonicus to see how individuals would react when exposed to members of the opposite sex.

They placed a female tardigrade in one sealed ‘arena’ and a male in another, with another tardigrade in the middle. Then they recorded the behaviour of the middle water bear. “In the water environment, males were spending more time next to females than next to males,” said Chartrain. T

This article is from...

How It Works Magazine

18 January 2024

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