SUNDAY TELEGRAPH(LONDON), March 21, 1999, Sunday, Pg. 14
HEADLINE: Insect that is spot on at weather forecasting NATURE WATCH
BYLINE: By GREG NEALE
BODY:
CAN a small insect predict the weather five or six months ahead? A
Cambridge scientist is beginning to think so.
Michael Majerus, a zoologist and geneticist, has been studying the
overwintering behaviour of the orange ladybird (Halyzia 16-guttata) for
more than a decade. In that time, he has observed a striking
relationship between the insect's choice of where it passes the winter
months and the ensuing weather.
The orange ladybird - identified by 16 white spots on an orange body
- prefers one of two sites to overwinter, Dr Majerus said. "One is on
the trunk or branches of smooth-surfaced trees, usually the sycamore,
which hosts a fungus on which it feeds.
"The ladybird finds a little crevice, a knot-hole or similar refuge,
usually in a relatively sheltered position at least 3ft above the
ground, away from the prevailing wind and where it will not be affected
by rain. The other type of site for the insect to spend the winter is in
dead leaves on the ground - usually in dried, curled leaves that provide
shelter.
"Whichever the site, we've noticed that the ladybird tends to go
there in late September or early October and remains there - unless it
is disturbed - until the spring, which can mean a stay of six months or
so."
The insect's choice appears to be linked to its weather forecasting
abilities. "The site seems to be correlated with how harsh the coming
winter is going to be," he pointed out. "When the winter is a mild one,
the ladybird tends to have chosen to stay in the trees. But if the
winter is going to be harsh, the ladybird tends to go to ground."
He added: "I have absolutely no idea how they do it, but in the 11
years we've looked at it, they have been correct every year. It is now
statistically significant that they are not making the wrong choice."
Dr Majerus is one of Britain's leading experts on the ladybird, and
is the author of an enjoyable and scholarly study of them. But he is not
yet ready to suggest an explanation for the orange ladybird's
behaviour.
"I have no idea and I really don't want to speculate," he said. "But
I have to say, no meteorologist has ever been able to tell me of
anything observable in September or October which enables them to make a
prediction of what the next six months are going to be like. I've never
come across anything like this." There are, he says, examples in the
animal world of species which react to changes in the weather, or to
seasonal climate. Some bird species, for example, seem to vary the
number of eggs they lay according to just how severe the preceding
winter has been: a mild winter will mean greater numbers of the insects
the birds prey upon in the spring. But the orange ladybird seems to be
behaving in a way which predicts the winter weather.
Dr Majerus's research is to be featured in a BBC 1 television series,
Supernatural, which begins on March 30.
John Downer, who made the series and has written an accompanying
book, said: "This could have profound implications for our understanding
of nature. We've all heard so-called countrymen's tales about trees that
fruit heavily before a hard winter, but this is possibly the first
evidence of a creature which can predict weather patterns that
meteorologists would normally say are chaotic."
James Honeyborne, who produced Hidden Forces, the programme in the
series which includes Dr Majerus's research - to be broadcast on April
13 - said: "There is an increasing amount of evidence which suggests
that some creatures are aware of things that humans are not, including
the suggestion that some animals can detect the imminence of earthquakes
from infrasound or the distortion of local magnetic fields.
"It's easy to be sceptical, but since I began to work on this series,
I've certainly become more open-minded."
Supernatural: The Unseen Powers of Animals by John Downer is
published by BBC Worldwide, pounds 18.99.