Life Nature Magazine

EVOLUTION FROM DUSK UNTIL DAWN AUTUMN ISSUE
Bats have evolved many different adaptations, their skull shape determines their
ability to produce sonar either orally or nasally.
Jamaican fruit bat Artibeus
jamaicensis (nasal sonar)
Greater mouse eared bat
Myotis myotis (oral sonar)
The pressure for both bats and moths to be highly
effective at their own game has escalated into an
evolutionary arms race, with each party continually
updating and fine-tuning their biological weapons.
University, US, have recently
against at least four species
of Myotis spp. bats in their
natural habitat in Arizona.
Sonar jamming can give the
moth those essential extra
seconds it needs to escape and
survive.
The pressure for both bats and
their own game has escalated
into an evolutionary arms race,
with each party continually
biological weapons. Hunting
with sonar in bats has selected
on moths to avoid predation
bias in the ability to detect
ultrasound. In turn, the evasive
use of ultrasound against the
tuning of sonar techniques
in bats. The Palaearctic pond
bat (Myotis dasycneme) can
switch between the type of
sonar that it uses, alternating
the frequency and pitch of
ultrasonic clicks in response
to moth activity. It can also
basic trawling along the water
surface to a form of aerial
hawking. Some bats even go
into silent or ‘whispering’
mode when making their
sneak up on their target. With
each escalation in biological
weaponry, there must be a
greater investment in energy,
physiology and behaviour.
Whether an evolutionary arms
race between bats and moths
will conclude with a winner or
cycle continuously is hard to
group of insects that make up
insectivorous bats’ diets and
there are many others that
make far easier prey items. In
the meantime, there is plenty
of entertaining research to be
done for curious and creative
biologists eager to follow the
game.
organism to a hunting bat must surely go to
the Tiger moth (Bertholdia trigona), which
produces a series of ultrasonic clicks that
serve to ‘jam’ the signals of hunting bats.
This is an exceptionally tricky and precision
piece of defence as the moth clicks must
If successful, moths can disrupt the auditory
the returning echoes and so ‘jam’ the
sonar signal. Biologists from Wake Forest
Written by Dr
Michelle Taylor,
Associate Research
Fellow at the
University of Exeter,
Cornwall Campus.
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