26
Invertebrates
Spiders
Found in 1997 by Andrew Middleton, but not
confirmed until 1998, was Tetragnatha
striata, a new species for the county. It was
found on Phragmites on the margins of Wake
Valley Pond, a site that keeps producing
exceptional records.
Odonata
Compared with 1997, it was a poor year in
terms of numbers of the early fliers in Epping
Forest, including the nationally scarce downy-
emerald (Cordulia aenea). Compared with
over 1200 downy emerald exuviae recorded in
1997, there were less than 300 in 1998.
However, the great news was that this species
had recolonised the Lower Forest Lake near
Epping, a site it had been lost from in 1991
following pond restoration work.
The other early flying dragonfly, the hairy
dragonfly (Brachytron pratense), continued
its spread into Essex colonising Epping Forest
in 1998 (although it may also have bred in
1997). It was seen at two ponds, Warren Pond
on 17th May during an Essex Field Club
excursion and at the Wake Valley Pond, where
it appears to be breeding successfully. With
the addition of this new species, Wake Valley
Pond, less than 2 acres in expanse, supported
16 breeding Odonata species in 1998. There
were no records for Orthetrum cancellatum or
Calopteryx splendens, which have also been
recorded breeding there in the last 20 years.
Lepidoptera
Gypsy moth (Lymantria dispar), a serious
pest species found in Europe and N. America,
was discovered in Epping Forest in 1995. This
was the result a release of captive-bred
individuals into a garden in Woodford Green,
probably in 1994. Since then MAFF, the
Forestry Commission and the Corporation of
London have been trying to locate and catch
as many individuals as possible within
Walthamstow Forest (TQ 392 908) and its
surroundings. This has been done in a number
of ways. Most important has been the annual
trapping of males using pheromone traps in
August (see table 1). but there have also been
caterpillar searches and egg mass searches.
Egg masses have been found in the gardens at
the centre of the outbreak in each year except
1998. Amazingly, given the needle-in-a-
haystack nature of the search, I found an egg
mass under split bark in an oak tree in the
centre of Walthamstow Forest in 1997. This
was bad news as it proved that the moths were
no longer emanating only from the gardens
where the outbreak first occurred. The gypsy
moth was now breeding 'in the wild' in
Britain for the first time ever.
Although many caterpillars have been found
in the gardens and much defoliation has been
recorded there, there has been no evidence of
their activity within the Foresl. Adult male
numbers have also been declining, probably as
a result of the cold wet springs of 1997 and
1998.
In 1998 the moth numbers, although low,
seem to have levelled out. To add to this, a
male moth was trapped at least 1km from the
epicentre of the original outbreak, 500 metres
further than any previous catch. So far in 1999
no egg masses or caterpillars have been
located. An update on the 1999 records will
appear here in the next edition of the Essex
Naturalist.
Table 1
__________________Adult male moths__________________
Year Forest catches garden catches TOTALS
1995 4 32 36
1996 18 12 30
1997 2 6 8
1998________3_____________7__________10
Essex Naturalist (New Series) 16 (1999)