Observation of the Wood White Butterfly Leptidea sinapsis (L.) (Lepidoptera:
Pieridae) in Devon
Dr Peter G Sutton 13 Oatlands, Gossops Green, Crawley, West Sussex. RH11 8EE
Introduction
In 1991, the Wood White Leptidea sinapsis was described by Thomas and Lewington as ‘a
declining rarity’ in mainland Britain, and at that time, there were estimated to be
approximately 90 Wood White colonies left in suitable habitat in England and Wales. The
four remaining strongholds for this species were given as: the east Midlands and localities
in Northamptonshire and Oxfordshire; certain well-wooded areas on the Wealden clays of
Sussex and Surrey; the Forests of Dean and Wyre and localities in Worcestershire and
Herefordshire; and finally, south Somerset and east Devon, ‘where some of the finest
colonies breed on scrubby undercliffs, west of Lyme Regis’ (Thomas and Lewington,
1991).
Indeed, Devon has always been a stronghold for the Wood White and when, at the turn of
the century, this butterfly so dramatically disappeared from many counties because of the
decline in woodland coppicing, colonies were lost from all but Devon, Hereford and
Monmouth (Ford, 1945). The subsequent revival was due largely to the creation of habitat
through the planting of great swathes of conifer plantation across the country, and in short,
the observed decline today has much to do with the loss of that habitat as breeding sites
have become too shaded to support colonies. The influence of shade on butterfly numbers
in woodland rides (with special reference to the Wood White) has been studied in detail by
Warren (1985), and indicates that the Wood White will not tolerate shade levels of greater
than 50%.
In recent years, several observations on the status of the Wood White have been reported in
British Wildlife magazine. The general consensus of these reports (1997-2000, compiled by
Nick Bowles, Butterfly Conservation) is that fewer colonies have been seen, with lower
numbers than expected from the sites observed, and that the poor weather conditions
experienced over the past three years have exacerbated the continuing decline of this
species. That said, traditional strongholds appear to be fairly stable, and observations of
first and second brood Wood Whites in Surrey (Sutton, 2000), and second brood specimens
in south-east Devon were recorded in 2000.
The status of the Wood White in
Devon has been described in detail by
Bristow, Mitchell and Bolton (1993),
and recently updated by Bristow
(2000). The latter work reports the
disappearance of the Wood White
from several of its few remaining
haunts in Devon, but thankfully, the
strong colonies associated with the
wood and scrub of the east Devon
undercliffs (which are probably
under-recorded) are still present. A
current distribution map (Devon BCS
Millenium Atlas 99) is reproduced in
Figure I.
This article concerns the observation
of second brood individuals from the
undercliff area to the east of
Branscombe Mouth on the south-east
coast of Devon.
Figure I Current distribution of the Wood White Leptidea sinapsis in Devon. (Reproduced by kind
permission of Devon Butterfly Conservation Society.)
Observations at Branscombe undercliff (5-6 August 2000)
During a weekend of monitoring the Scaly Cricket Pseudomogoplistes vicentae (formerly
P. squamiger) on the stretch of shingle beach between Branscombe Mouth and Beer Head,
several observations of second brood Wood Whites were made. The first of these occurred
along the undercliff path (SY212882) as I was walking west from the Hooken Landslips
with my companions. A single female Wood White was flying close to the steep sided
hedge to the right of us (behind which were dense scrub and trees smothering the
undercliff), and to the left was a steep sloping drop of 50-60 yards down to the shingle
beach below, again covered in a mixture of dense scrub, wind-stunted trees and occasional
areas with low scrub and grass where recent slippage had occurred. This female was
extremely difficult to approach and photograph, seldom landing, and eventually
disappeared from view. Luckless, and turning my attention to some Ivy Broomrape that
was growing by the side of the path, a white flash in my line of vision signalled the return
of this elusive creature. I turned
cautiously to watch the Wood
White as it landed on foliage at
the side of the path, and
approached as slowly as possible
until the butterfly was in focus
(Plate I).The time was
approximately five o’clock, and
after a hot and sultry afternoon,
the humid air was still perfused
by the sun’s warm rays. To my
amazement, a male Wood White
fluttered down and landed face to
face with the female, and a
courtship display began not three
inches from the front of my
camera lens! (Plate II).
Plate I (left) Second brood female
Wood White Leptidea sinapsis at Branscombe undercliff.
Plate II (right) Arrival of male Wood White
and initiation of courtship behaviour.
As soon as the male arrived, the
courtship behaviour began with the
mutual tapping of antennae.
Subsequently, the male slowly
uncoiled its proboscis, and raised it
above the head of the female (see front
cover of this bulletin). The courtship
behaviour of the Wood White has been
studied in detail by Wiklund (1977a,
1977b), who states that ‘during this
procedure, no part of the male would
touch the female, although the
proboscis of the male almost encircled
the head of the female’. From my
view point, it appeared that the male was actually regularly tapping the female
with
its proboscis, but that illusion was created by the left and right semi-circling motion of the
proboscis. However, Wiklund (1977a) does state that an unreceptive female remains
motionless throughout the display, and in this instance, this was not the case. As the male
circled its proboscis and issued its antennae back and forth, it would give a single rapid flap
of its wings. Each time that happened, the female would respond with a single rapid wingflap of her own. This behaviour was maintained throughout the three-minute display. At no
point during the display did the female attempt to curve her abdomen towards the male to
show her willingness to mate, and the male soon departed. This ‘departure’ from
unresponsive females is a fascinating aspect of the courtship display of this species, and the
observed monogamy of the Wood White has been studied in detail by Wiklund (1977b),
and confirmed by Warren (1984). The courtship behaviour of the Wood White is unique in
two respects. Firstly, unmated females will always display their willingness to mate by
curving the abdomen towards the male (with the probable release of a pheromone during
that process), and secondly, as observed above, males are completely “non-insistent” in the
absence of this signal. Warren (1984) noted from fifty separate observations at Yardley
Chase in Northamptonshire, that unsuccessful courtships lasted between 0.5min and
5.5min, with the average time of male departure being 1.5min. Wiklund and Warren both
observed that females, once mated, did not mate again, confirming their apparent
monogamy.
On the second day (6th August), several more Wood Whites were seen close to the shingle
beach mid-way between Branscombe Mouth and Sherborne Rocks SY215880. They
seemed to be pre-occupied with a site which was rich in leguminous plants, and contained
very wet areas of water seepage devoid of vegetation, from which the Wood whites could
be seen imbibing water and nutrients. The dominant leguminous plant appeared to be one
of the Lathyrus vetches, and by its size and pink flowers, was probably that widespread
garden escape, the Broad-leaved Everlasting Pea Lathyrus latifolius. Much as the Wood
Whites were interested in these vetches, none were seen to lay eggs during the brief period
that they were observed between 11am and 1pm. Six adults were seen that day at this site
and on the undercliff path, and one individual took an adventurous foray out onto the open
shingle for 20 yards or so before returning to the undercliff flush area. Bizarre as it may be
to see a Wood White on the beach, Barrett, in 1906, stated that the Wood White was still to
be found ‘in abundance’ on the cliffs east of Sidmouth, and between there and Beer, flying
on broken slopes of the cliff, and even over the shingle down to the sea. (Bristow, Mitchell
and Bolton, 1993).
Other species recorded at Branscombe on these dates were: second brood Dingy Skipper
Erynnis tages, many Large Pieris brassicae and Green-veined Pieris napi Whites, Small
Purple-barred Moth Phytometra viridaria, Magpie Moth Abraxus grossulariata,
Hummingbird Hawkmoth Macroglossum stellatarum, many Glow-worms Lampyris
noctiluca, Bloody-nosed Beetle Timarcha tenebricosa, Great Green Bush-cricket Tettigonia
viridissima, Grey Bush-cricket Platycleis albopunctata, Rufous Grasshopper
Gomphocerippus rufus, Meadow Grasshopper Chorthippus parallelus, Common Field
Grasshopper Chorthippus brunneus, Common Groundhopper Tetrix undulata and the Scaly
Cricket Pseudomogoplistes vicentae (which continues to thrive along the Branscombe-Beer
Head stretch of shingle.)
References: Bowles, N., British Wildlife, 1998, 9, p.391; 1999, 10, p.429; 2000, 11, p.363, p.437; Bristow, C.R., British Butt. Cons. Soc.
(Devon Branch) Newsletter, 48, 3-5; Bristow, C.R., Mitchell, S.H. and Bolton, D.E., 1993, Devon Butterflies, Devon Books; Ford, E.B.,
1945, Butterflies, London: Collins; Mitchell, S.H. (Ed.), British Butt. Cons. Soc. (Devon Branch), Millenium Atlas 99; Sutton, P.G., 2000,
Bull. Amat. Ent. Soc., 59, pp.166-172; Thomas, J. and Lewington, R., 1991, The Butterflies of Britain and Ireland, London: Dorling
Kindersley; Warren, M.S., 1984, Entomologist’s Gazzette, 35, pp. 207-223; 1985, Biological Conservation, 33, pp. 147-164; Wiklund,
C., 1977a, Oikos, 28, pp. 56-68; 1977b, ibid., 29, pp. 275-283.
Acknowledgements: I am indebted to the following for their kind assistance in the preparation of this article: Martin Warren, Roger
Bristow, Simon Mitchell, Nicola Baccui, Devon Butterfly Conservation Society. I would especially like to thank David Hanz Browne and
Karl Browne for their most excellent company.