Tough Tardigrades: Scientists Uncover Mystery of How Water Bears Mate
For the first time, scientists have unraveled the mystery of how tardigrades, some of the toughest creatures on the planet, mate. These tiny, hardy critters have few obvious differences between males and females, making it unlikely that they found mates by sight alone. It turns out, females may release a chemical cue that lures the males, researchers found.
Tardigrades, also known as “water bears” thanks to their chubby appearance, can tolerate extreme conditions. For example, they can survive a combined exposure to the vacuum of space, cosmic radiation and UV radiation. However, male and female tardigrades are hard to distinguish, with only size differences and 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, researchers performed a series of experiments with the species Macrobiotus polonicus to see how individuals would react when exposed to members of the opposite sex.
The researchers found that in water environments, males were spending more time next to females than next to males, suggesting that the males could smell the females in their chamber and were lured by it. Additionally, when tested in a Jell-O-like substance called agar, the study revealed that the tardigrades could only locate opposite-sex mates in water environments and that only the males actively seek out females for mating.
These findings provide valuable insights into the mating behavior of tardigrades and shed light on the unique mechanisms through which these remarkable creatures find and mate with each other. The study was published in the November issue of the Journal of Experimental Biology, offering a groundbreaking look into the reproductive habits of these resilient water bears.