Page 83 - BBC Wildlife Volume 36 #10

HORNETS
important task of raising the temperature of
the cells they sit on. The way in which social
insects can control the temperature of their
nests is quite incredible. Not only can hornets
warm up cells, but they can also reduce the
temperature by rapidly beating their wings to
fan the cells or by delivering and spreading
cooling water to the surface of the cells.
The first brood of adult workers takes over
the nest-building work and looks after the new
broods hatching from the queen’s eggs. So the
colony grows. Every second counts to ensure
its survival. “Hornets will continue to fly well
Asian hornet: Michel Gunther/Biosphoto/Alamy out. “Like moths, they’re attracted to the lights mate with only a single male. This is not pages show, these unsung heroes of the insect
after dark on warm evenings all through the
summer and early autumn,” Stephen points
in our homes. So hornets can be seen circling
outside security or porch lights, or flying up
and down lit windows.”
Things don’t always go to plan, however.
There are a number of guests – some possibly
unwelcome – sometimes to be found within
the hornet nests. Some are simply scavenging
and feeding on left-overs within the nest,
October 2018
but there are some beetles and parasitic wasps
that will feed on the developing brood.
Later in the season, the internal
architecture of the nest changes, as large cells are masterminds of architecture and social
are built to accommodate the rearing of new
queens. At this stage males, characterised by
their long, black antenna and lack of a sting,
will also be produced, but they will usually be
assigned the smaller cells. Before the onset
of winter, the founding queen is neglected
by the workers and she dies.
Annual life-cycle
Now the young queens and males emerge
from the nest and mate. Most queen hornets
always the case, however: sometimes a queen
might mate with two or three males, but
even in that scenario, most of the queen’s
offspring will be eggs fertilised by only one
of the males, so the female workers are still
extremely closely related. Following mating,
the workers all gradually die off.
the queens settle down for the winter and
Alien arrival:
Asian hornet
The Asian, or yellow-legged, hornet is
native to South-east Asia, and was first
seen in Europe in south-west France in
2004, probably having been introduced as
a stowaway in pottery imported from China.
It has since spread across France, and there
are now records from the Channel Islands,
too. Since 2016 there have been isolated
sightings in southern England, but any nests
were rapidly eradicated. There are concerns
about the species’ impact on biodiversity,
particularly pollinating insects, because of
its wide range of prey. A recent study
showed that the Asian hornet is more
effective than the European hornet at
establishing new nests, and it is also
considered bolder and more active and
exploratory than its European cousin.
O Report sightings using the free
‘Asian Hornet Watch’ app, or online at
nonnativespecies.org/alerts/asianhornet
The magnificent sight of hornets in flight is
cause alone to stop and watch, but when you
delve a little deeper, you realise these wasps
organisation. “The ways in which individuals
within a colony work together is inspiring and
captivating in equal measure,” says Stephen.
If you are fortunate enough to see hornets,
then please do, like Stephen, take your time
to observe them. Enjoy the behaviour of these
incredible aerial predators, though keep a safe
distance and don’t cross their flight paths.
While Stephen has spent “countless happy
hours” very close to hornet nests, this is not
without its risks. But as his pictures on these
world are worth celebrating.
HELEN ROY is an ecologist at the
Centre for Ecology and Hydrology
and an expert on non-native species.
FIND OUT MORE Bees,Wasps and
Ants Recording Society: bwars.com 83
BBC Wildlife