Page 86 - BBC Wildlife - August 2017 UK

7-SPOT LADYBIRDS

“ SEVEN NATIVE SPECIES WERE

DECLINING IN RESPONSE TO
THE NEWCOMER’S ARRIVAL.”

A similar proportion of overwintering ladybirds die
from fungal infection. The soil is rich in fungi and some
of these are pathogenic to ladybirds. We have shown that
ladybirds can detect patches of soil where pathogenic
fungi are particularly abundant, and thus avoid
overwintering there, and they will also move away
from their infected counterparts.
But there are new threats. Britain is changing.The
climate is warming, we are putting ever-more pressure
on the land through urbanisation and agricultural
intensification, and the speed at which new species are
arriving either as natural colonists or deliberately introduced
by us is accelerating. Of course, the planet has always
undergone periods of dramatic change, but perhaps the
biggest difference now is the way in which humans are
orchestrating thechange.
Above (left):
abraconid 5 OTHER
ALIEN INVADERS
ckw nke /A amy (x3); /A amy fe/A amy; Redmond Durre What does this mean for 7-spot ladybirds? For ladybird ovipositor to LADYBIRDS
wasp uses its
insert an egg into
communities, perhaps the most noticeableand relevant
TO SPOT
the abdomen
perturbation in recent times has been the arrival of the
of a 7-spot;
harlequin ladybird.This species was introduced into
Below: harlequin
eft: K m Tay or/naturep .com; Ern e Janes/naturep .com; b d o/A amy; R chard Becker/FLPA; C arence Ho mes W its way to Britain as a stowaway and by flying across the native ladybird native) harlequin 14-SPOT
Once you’re familiar
mainland Europe in the 1980s as a biological control agent
ladybirds
are causing
of pest insects. It was only a matter of time before it made
with 7-spot and (non-
populations
ladybirds, here are
English Channel. In 2004, the first record of this species
to decline.
five more common
was reported to theUKLadybird Survey, since when many
ABUNDANCE: ● ● ● ● ●
species to look for in
thousands of people have helped to track its rapid spread.
The distinctive 14-spot ladybird
Britain, listed in order
The records received from across Britain have allowed
is yellow, with square-shaped
of abundance.
us to explore the ways in which the harlequin ladybirdladybird
is affecting the distribution of other ladybirds. The
black spots (there are normally
results are stark. Seven out of the eight native ladybird
14, though fewer is possible).
newcomer’s arrival. This is not surprising:thee harlequin
ladybirds, it feeds on aphids and
C ockw se from top Pap species we investigated were declining in respponse to the Like the 2-spot and 7-spot
is commonly found on farmland.
is highly voracious and consumes many inseccts,
including ladybirds. It also wins when in
It has a long overwintering
period, emerging as late as May.
competition for aphids with the other ladybirdds.
So which species of the eight was unaffected? Our
86 BBC Wildlife August 2017