18 | New Scientist | 30 January 2021BiodiversitySwimming machine
cracks squid motionROBOT squid that move with
a certain rhythm can match
the power efficiency of the real
animals, a trick that could be used
for designing new submarines.
Real squid have small fins for
slower manoeuvring, but when a
big burst of speed is required, they
suck in and expel water to propel
themselves. Researchers have
tried to build robots that mimic
this jet-like behaviour, but nowData reveals racial
bias in recruitmentPEOPLE from ethnic minorities
are less likely to be contacted by
job recruiters than people from
the majority group, according
to an analysis of users on a Swiss
public employment website.
Dominik Hangartner at ETH
Zurich in Switzerland and his
colleagues studied the actions
of more than 43,000 recruiters
who conducted 450,000 searches
of 17.4 million jobseeker profiles
between March and December- They tracked every click to
see how recruiters interacted with
the profiles, which include details
of ethnicity, age and nationality.
How often Swiss nationals
born in the country and from
the majority ethnic group were
contacted by recruiters was the
baseline for the analysis. People
from immigrant and ethnic
minority groups were up to 19 per
cent less likely to be contacted.
Society^ BiomimeticsTHE number of bee species
recorded worldwide has been
sharply decreasing since the 1990s.
Eduardo Zattara and Marcelo
Aizen at the National University
of Comahue in Argentina analysed
how many wild bee species are
observed each year, as recorded
in the Global Biodiversity
Information Facility – a database
where researchers and enthusiasts
can record species sightings.
They found a quarter fewer
species were reported between
2006 and 2015 compared with
the records we have from before
1990 (One Earth, doi.org/frvc).
The decline is especially alarming
considering the number of bee
records in this database has risen by
around 55 per cent since 2000, so
it isn’t due to a lack of observations.
“Our work is the first long-termassessment of global bee decline,”
says Zattara. Previous bee research
has been confined to a specific
species or a particular location.
It doesn’t necessarily mean that
unrecorded bee species are extinct,
but they are now rare enough that
people who tend to report bee
sightings aren’t encountering them.
The destruction of natural
habitats, pesticide use and climate
change could explain this decline
in species richness, says Zattara.
The global decline mirrors what
has previously been reported in the
UK. But the researchers note that
studies in more remote areas are
needed to gain a full picture.
“These declines are alarming for
food security and the health of the
natural world,” says Gary Powney
at the UK Centre for Ecology and
Hydrology. Karina ShahQuarter of all bee species
not seen for three decades
a team led by Gabriel Weymouth
at the University of Southampton,
UK, has discovered a way to do so
at high efficiency.
Weymouth and his colleagues
created an umbrella-like robot
with eight plastic ribs covered by
a rubber skirt (mock-up pictured).
This structure flexes out to suck
in water and contracts to expel it,
providing thrust.
The team tried the robot at
a range of opening and closing
rates, comparing energy in and
out to measure its efficiency.
Firing pulses of water at the
natural resonance of the robot’s
propulsion mechanism resulted
in an efficiency that was 100 times
greater than at other frequencies,
matching the most efficient squid
(Science Robotics, doi.org/frj9).
This effect is similar to how
pushing someone on a swing at
just the right moment makes
them swing slightly higher each
time. Weymouth hopes the design
could one day be adapted to power
submarines. Matthew SparkesRecruiters spent only
0.3 seconds less, on average,
on profiles of ethnic minority
jobseekers, which the researchers
say means the result can’t be
entirely explained by recruiters
consciously discriminating
against people based on ethnicity.
But the time spent on a profile
varied depending on time of day:
between 9am and 10am, it was
10.5 seconds on average per profile,
and 12 per cent less on those from
minority ethnic backgrounds.
Between 5pm and 6pm, recruiters
spent 9.5 seconds on the average
profile, and 14.7 per cent less on
ethnic minority accounts. Similar
variations are found just before
lunch breaks. For the average job,
no significant difference was
found based on the gender of
applicants (Nature, doi.org/ghts9f).
“This kind of analysis shows
racial discrimination is still
deeply entrenched,” says Safiya
Umoja Noble at the University
of California, Los Angeles.
Chris Stokel-WalkerED
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2971News In brief