Planktonic sea urchin larvae change their swimming direction in response to strong photoirradiation

Sea-urchin larvae go into reverse in strong light

29 July 2022

The larvae of sea urchin start swimming backwards on exposure to strong light — a finding that fills in a missing piece in how light-responsive systems developed in animals.

Almost all living organisms react to light in some way. In advanced animals, the response is mediated via the central nervous system to muscles. In contrast, many microscopic aquatic organisms use hair-like cilia to move in response to light.

The cilia-based response is thought to have developed first, but it has been difficult to measure cilia responses in organisms having both cilia and muscles because muscles tend to be much stronger than cilia.

Now, five researchers, all from the University of Tsukuba in Japan, have found that sea urchin larvae use their cilia to swim backwards when they are illuminated by strong light.

This finding will help scientists better understand how light-responsive tissues developed in animals, the researchers say.

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References

1. PLoS Genetics 18, e1010033 (2022). doi: 10.1371/journal.pgen.1010033