8 January 2022 | New Scientist | 25Electric feel
THE starfish in this image looks
suitably electrifying, but the
lightning-like currents emanating
from this male Leach’s sea star
are actually streams of sperm.
The shot was taken in Kagoshima
prefecture in Japan by nature
photographer Tony Wu.
Starfish sexually reproduce
by a process called spawning,
with many individuals releasing
great quantities of eggs or sperm
into the water from their sexual
organs, located in their arms.
Congregating in groups boosts the
chance of the eggs being fertilised,
whereupon they will develop into
planktonic larvae that are carried
by the currents.
This sea star is spawning in
synchronisation with others
nearby, as dictated by the time
and flow of the tide, but that isn’t
its only reproductive tactic. Just
like other starfish, Leach’s sea stars
(Leiaster leachi) can also asexually
reproduce if their arms become
detached or damaged. As long
as part of their core – the central
disc – is intact, they can restore the
lost arm or regenerate their entire
body from the arm.
Leach’s sea stars are found
on rocky shores and corals,
spanning the seas of east Africa
to South-East Asia, Japan, Australia
and Hawaii. ❚
Gege Li
Photographer Tony Wu
Agency Naturepl.com