20 BBC WILDLIFE December 2021
C
leaner wrasse have long been
suspected of punching above their
weight intellectually. They are the only
fish known to recognise themselves
in a mirror and can remember events
that happened months previously.
And according to new research, they can
understand what others know, too.
These colourful little coral-reef fish
are famous for operating cleaning stations
where, working in teams, they remove
parasites and dead tissue from the bodies of
visiting ‘client’ fish.
However, the wrasse
are also partial
to their clients’
nutritious skin
mucous. Giving inSomething fishy
The coral-reef fish that is less likely to ‘misbehave’
when it knows it’s being watched by its co-workers
IN BRIEF
Bird botanists
Birds learn to avoid the plants that
toxic insects are found on, according
to a study from the University of
Bristol. Fake cinnabar caterpillars with
and without warning coloration were
stashed on ragwort (where they dwell)
and bramble (where
they don’t) and
the birds
avoided all
those on the
ragwort, even
those without
the coloration.WHAT IS IT?
A beautifully coloured tiger beetle species
that so far has been found in only two
saline, muddy ditches. A total of 18
specimens were collected back in 1992
and 1994, but only with modern taxonomy
methods have they been identified as a
new species.WHERE IS IT?
Little is known about the full distribution of
this species, as it was collected from two
sites in the state of Coahuila in northern
Mexico. The extension northwards of the
ridge and basin in which the species was
found could mean that it may also be found
in west Texas in the USA.WHAT IS THE MEANING BEHIND THE
SCIENTIFIC NAME?
The name mecocheila describes its labrum,
comparable to an upper lip, which is more
elongated than in similar species. The word
is derived from Greek where ‘meco’ means
long and ‘cheila’ means lip.
Find out more: bit.ly/3CDdvgkEunota
mecocheila
to temptation, though, causes the client to
flee and their co-workers to miss out on a
meal, so greedy fish are liable to be punished
with violence by their team mates.
The new study, published in the journal
Communications Biology, demonstrates that
wrasse are more likely to grab a mouthful
of mucus if they cannot be seen by their
colleagues. This ability to gauge what other
individuals know and adjust one’s own
behaviour accordingly – known as theory of
mind – has so far only been witnessed among
apes and corvids.
“One of the more exciting take-aways from
this particular study is that building blocks of
theory of mind – such as strategically changing
behaviour depending on whether or not
you’re being watched – can emerge across a
really wide range of taxa and does not seem
to depend on big brains,” says psychologist
Katherine McAuliffe, who led the work at
Boston College, Massachusetts.
Stuart Blackman FISH:REINHARDDIRSCHERL/GETTY;^ BEETLE:^DANIELP^DURAN^&^ STEPHENJ^ROMAN;CATERPILLARS:^ CALLUM^MCLELLANMcAuliffe is a
psychologist and
associate professor at
Boston CollegeCleaner wrasse
working cooperatively
feeding on a ‘client’
surgeonfish¡Hola! Mexico has
a handsome new
tiger beetleNEW SPECIES DISCOVERY