20.
GREEN IS BEAUTIFUL
During our ramble to listen for nightin-
gales at Mill Green last May, one of our
younger members spotted a small moth flying
across a ride. It came to rest on the bright
green leaf of a coppiced Sweet Chestnut tree.
The moth was about 11/2 cm, long, bright green
and had three diagonal lines across each wing.
We could easily imagine the camouflage value of
the leaf green colour and the vein like
markings. This was a Green Silver Lines moth,
Vena prasinana, belonging to the family of moths
called the Noctuidae. Generally the noctuid
moths are drab in colour, although many of the
larger ones such as the red Underwing and orange
Underwing have, as their name suggests, brightly
coloured hind wings. These they are supposed
to flash at attacking birds in an attempt to
frighten them away. Our moth at Mill Green was
certainly not dull and did not flash its wings
at us. It was one of several noctuid moths
having green wings.
Green however is an unusual colour for
butterflies and moths although it occurs
perhaps more commonly in these than elsewhere
in the animal kingdom (can you think of any
green mammals). It occurs more widely in moths
of the family Geometridae, those having "looper"
caterpillars, that resemble small twigs until
they start moving with their characteristic
looping action caused by only having legs at
each end of their long thin bodies. Of the
geometrid moths it is the "Emeralds" that are
green. Eight different Emerald moths are found
in Essex. Several of these are quite rare but
others are frequently met with. They have wide
papery thin wings. One of the rarest of these
moths is the Essex Emerald that feeds on sea
wormwood along the edges of the coastal salt