BBC Wildlife - UK (2019-12)

B

eing loners that parasitise the social
systems of other species, cuckoos
have less need than most birds for
complex vocal communication. But they do
have a little more to say than just “cuckoo.”
Only the males make the iconic two-syllable call,
which is mostly deployed in competition with rivals.
But they also have a three-syllable version – “cuck-
cuckoo” – which seems to have more to do with
attracting mates. Females themselves produce a
bubbling chuckle. This has long been suspected to
mimic sparrowhawks in order to scare host species
from their nests before the cuckoo lays her parasitic
egg. But it also seems to be associated with the
male’s three-syllable call, suggesting that both are
involved in sexual communication. Stuart Blackman

Do cuckoos make

any other sounds?

BRITISH BIRDS

A peacock butterfly,

probably with a few

stories to tell.

Male cuckoos

are actually

two-trick

ponies when it

comes to that

famous call.

Female bonobos have

five or six ospring in

their lifetime, caring

for each youngster

until it reaches four or

five years of age.

Y

es. The process of ageing

is associated with physical

andbehavioural changes in many

species,and insects are not immune

to this. Obvious wear and tear such as

missing scales on butterflies and moths,

bald patches on bees, and torn, fraying

wings can reflect an individual’s level

of activity and lifestyle, but there are

also physiological changes taking place

as time passes. The flight muscles of

flies and bees can deteriorate with age,

for instance, reducing the frequency

of wingbeats and affecting the insects’

ability to fly for sustained periods.

Behaviour can also have an effect

on ageing, particularly in species that

engage in energetically demanding

activities. More rapid physical declines

are seen in territorial dragonflies (who

chase, bite and barge their rivals) than

their non-territorial peers, while field

crickets that put more energy into

reproduction in their youth call less

and are more likely to lose fights with

competitors. Laurie Jackson

Do insects show signs of ageing?

NVERTEBRATES

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