Comma No91 Spring 2015

Two White-letter
Hairstreak eggs
near the leaf bud
(Stephen Lewis)
The White-letter
Hairstreak is
widely distributed
across the
West Midlands
area but is not
often seen
because it
stays high up
in Elm trees
(David Williams)
Hairstreak egg-hunt training
pays dividends
A hardy bunch of West Midlands branch
members stormed the car park of Stafford
Castle in mid-winter for a short training course.
L
ocal
member Tony Moore has spent a life-time
studying butterflies and moths, and volunteered to
share some of his knowledge. The aim of the exercise
was to find the tiny overwintering eggs of the
White-letter Hairstreak butterfly. As Tony explained,
it is more difficult to find the adult butterfly than the
pin-head sized eggs, which are often the first indication
that this Hairstreak is present in an area. He had walked
the paths around Stafford Castle for over 20 years and
had only seen two adult butterflies!
Locating an Elm tree
After showing everyone some of his close-up photographs
of the target, the group set off around the castle grounds.
First thing was to locate an Elm tree big enough to have
flower buds (the larva’s first meal on hatching), but not
yet affected by the dreaded Dutch Elm Disease. The
caterpillars are fully formed within the egg all through the
winter and finally eat their way out in March to begin
feeding on the developing buds and flowers.
When about half-grown the larvae also consume the
younger leaves, and rest on the undersides. Around the
third week of May most larvae are nearly fully grown.
The pupal stage lasts about three weeks with the adults
Here’s one: Tony
Moore shows a
White-letter
Hairstreak egg to,
from left, Mike
Williams, Carol
Dent, Stephen
Lewis, Tony, Mike
Dent, Carol Wood,
Hugh Glennie and
Lucy Lewis
(Roger Wasley)
10
the Comma