22 August 2020 | New Scientist | 21PalaeontologyInsects AnthropologyAncient galaxy
is eerily peacefulA galaxy known as
SPT-SJ041839-4751.
is so far away that we see
it as it existed when the
universe – now some
13.8 billion years old –
was just 1.4 billion years
old. Such early galaxies
are predicted to have been
turbulent, but this one is
serene, testing our ideas of
how early galaxies formed
(Nature, doi.org/d6nh).Male frog stays
loyal to two femalesThe genetics of the tadpoles
of Thorapa taophora frogs
in the Brazilian rainforest
suggests that males stay
faithful to two females
throughout the breeding
season. This mating style,
known as single-male
polygyny with fidelity,
has never been seen in
amphibians before (Science
Advances, doi.org/d6ng).Cremation began
in the Stone AgeAn excavation in Israel has
uncovered the oldest known
evidence of cremation in the
region. The 9000-year-old
remains might hint that
Stone Age people were
beginning to change
their religious beliefs,
reducing the emphasis
on worshipping ancestors
(PLoS One, doi.org/d6nf).Trilobites had eyes
like modern insectsAN ANIMAL that lived 429 million
years ago had compound eyes
similar to those of insects like
bees and dragonflies. This implies
that the compound eye evolved
early in the history of animals.
“I am quite sure that its roots
lie far back in the Precambrian,”
says Brigitte Schoenemann at the
University of Cologne in Germany.
The Cambrian period, when many
major animal groups appeared,
began about 540 million years ago.A CHEMICAL released by locusts
encourages them to swarm. This
discovery could help us prevent the
insects destroying swathes of crops.
Locusts normally live solitary
lives, but can undergo a physical
change that makes them become
gregarious and gather in huge
swarms. Most control methods
rely on spraying swarms with
insecticide, which also harms
other organisms.
Le Kang at the Institute of Zoology
in Beijing, China, and his colleagues
investigated 35 volatile chemicals
that are emitted in greater
quantities by gregarious migratory
locusts (Locusta migratoria) then bysolitary ones. This widespread
species is found in Africa, Asia,
Australia and New Zealand.
Gregarious locusts seemed to
prefer one chemical in particular,
called 4-vinylanisole, and when
the team overcrowded solitary
locusts by placing groups of 30
in small cages, the insects began
emitting it within 24 hours
(Nature, doi.org/gg7vqk).
The locusts were drawn to sticky
traps baited with 4-vinylanisole
and the team suggests the traps
could be used to attract locusts
to a small area, which could
then be sprayed with insecticide
in a targeted way. MMWith Euan Clarkson at the
University of Edinburgh, UK,
Schoenemann examined fossils
of a 1.2-centimetre-long animal
called Aulacopleura koninckii.
It was a trilobite: a marine animal
a bit like a woodlouse.
Trilobites dominated the oceans
for 300 million years, beginning
about 520 million years ago,
and studying them offers clues
to the origins of related groups
like insects and crustaceans.
Schoenemann and Clarkson
found that one A. koninckii
specimen still had its left eye.
It was a compound eye, whichEarliest known beds
made of grass and ashPEOPLE living in a cave in
southern Africa slept on grass
bedding 227,000 years ago – by
far the oldest discovery of its kind.
Lyn Wadley at the University
of the Witwatersrand in
Johannesburg, South Africa, and
her team have been excavating
Border cave in South Africa, which
was inhabited in prehistoric times.
The peoples living there left many
layers of deposits that have been
preserved by the dry conditions.
The team found grass bedding
in many of the layers, made
from species including Panicum
maximum, which still grows
outside the cave. The oldest layers
containing bedding are between
227,000 and 183,000 years old.
The bedding was often on top
of ash layers. In some places,
the ashes are of burned grasses,
suggesting people burned old
bedding and placed new grass
on top. In others, the ashes are
of burned wood, suggesting ashes
from fires were spread out and
grass placed on top (Science,
DOI: 10.1126/science.abc7239).
The team also found burned
camphor wood – camphor is still
used as an insect repellent today.
“Maybe it was burned for the
smoke it creates that would repel
flying insects,” says Wadley. MLPcontains many tiny receptors
called ommatidia, each with
light-sensitive cells and a lens
to focus light. Each ommatidium
contributes a single “pixel”
to create a mosaic-like image.
The structures of its ommatidia
were almost identical to those
of modern insects. The only
difference was that they weren’t
quite as densely packed, probably
reducing the detail that the
animal could see (Scientific
Reports, doi.org/d6m7). But to
all intents and purposes, it was
a modern compound eye, says
Schoenemann. Michael MarshallChemical that spurs locusts to
swarm could also stop them
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