The Hemiptera of Devon
Although I have only recently moved to Devon I have been a regular visitor over the
years, both for work purposes and on holidays. My work used to involve surveying
National Trust sites for their invertebrate conservation interests and identifying the
land management implications. My visits were targeted by site rather than species.
But now that I am resident one of my personal projects is to document the county
Hemiptera fauna, particularly the Heteroptera. A preliminary review of what is
already known has identified a wide range of nationally rare or scarce species that
have been reported in the past, often long ago. This article picks these species out and
provides some basic information about their known habitat requirements.
Devon’s most famous bug is the firebug
Pyrrhocoris apterus, a black bug with red
markings and about 10mm long. Although
widespread on the continent, the only known
permanent colony in the whole of Britain is on the
rocky islet of the Ore Stone, barely 1km off
Hope’s Nose at Torquay. It has been known there
since at least 1865. It feeds on tree mallow,
especially the seeds. It is short-winged and so
does not fly. It seems likely that climate change
will encourage its eventual establishment on the
British mainland, probably helped by the garden
trade.
Although the rocky coasts of the south west are
also famous for other bugs, the majority of those
Pyrrhocoris apterus
species are confined to Cornwall. A few have
however been found in Devon, notably the oxeye seed bug Trapezonotus ullrichi (Red
Data Book Category 3) and the bird’s-foot-trefoil bug Capsodes sulcatus (Nationally
Scarce). These have a Mediterranean distribution in Europe and favour the warm
sunny frost-free climate of the sea cliffs of the far south-west of Britain. T. ullrichi
occurs on dry flowery cliff-top grasslands and is most readily found on the
flowerheads of oxeye daisy. I have found it at Hoist Point and at Sharp Tor, but the
original Devon locality was Babbacombe Bay – it is not known whether it survives in
this area. The Capsodes also likes flowery cliffs but favours large clumps of bird’sfoot-trefoil growing in bare or sparsely-vegetated areas on landslips. I have found it at
Gara Point by the mouth of the Yealm, and on Gammon Head. A third species, the
sheep’s-bit bug Strongylocoris luridus (Nationally Scarce) is also mainly a species of
the south-western cliffs and has been reported in Devon although I haven’t seen it
myself.
There are also a few bugs which live in dry usually base-rich grasslands and
presumably are most likely to be found in the county along the coast, perhaps the
chalk areas of the south-east. Catoplatus fabricii (Nationally Scarce) is a species I am
familiar with in the Cotswolds but have yet to encounter here in Devon. It is
associated with oxeye daisy where it grows in warm, well-drained and sunny sites,
and usually in short or sparse vegetation on long-established pastures. Ulopa trivia
(Nationally Scarce) is a scarce, largely south-eastern, species associated with
calcareous grasslands, possibly feeding
on Plantago lanceolata and other herbs.
It is known from the Lizard in Cornwall
as well as Devon.
The last speciality of rocky coasts which
deserves a special mention is
Aepophilus bonnairei (Nationally
Scarce). This is a south-west Atlantic
species living in rock crevices intertidally, in the Fucus zone between low
spring and low neap levels.
Trapezonotus ullrichi ovipositing
on Ox-eye Daisy
The land-slipping cliffs of south-east Devon have their own specialities. The shore
bug Saldula arenicola (Nationally Scarce) favours bare surfaces around seepages on
soft-rock cliffs, especially recent slippages. It is a characteristic component of the
seepage fauna of the soft rock cliffs along the south coast from Hampshire to Devon.
It has long been known from the area and the National Trust Biological Survey Team
found it at both Dunscombe and Weston in 1990. The Nationally Scarce stilt bug
Berytinus hirticornis has been reported from Devon and these cliffs are likely places
to find it – it occurs in this situation in Dorset and on the Isle of Wight.
Many bugs like the freely-draining sandy soils of sea-cliffs and coastal dunes. The
stabler terrain of head cliffs suits some species while others are more regularly found
in the looser material of the dunes. Rhyparochromus pini is a Nationally Scarce seed
bug which favours the former situation and I have found it at Baggy Point.
Braunton Burrows merits its own paragraph of course. It combines classic loose sand
species such as the hairy shield bug Odontoscelis dorsalis (Nationally Scarce) with
dune slack specialists such as Monosynamma sabulicola (Nationally Scarce). The
Odontoscelis favours rather small stunted plants of stork’s-bill growing in fairly firm
and stable sand, often where there is growth of moss. It is an active burrower and
completely at home in loose sand. Stork’s-bill tends to be an important foodplant for
dune bugs and supports other Nationally Scarce species such as Megalonotus
praetextatus. The Monosynamma is a speciality of south-west coasts and is usually
found with fairly dense stands of creeping willow adjoining short vegetation or bare
ground, which provide sunny and sheltered edges. Globiceps cruciatus is another
Nationally Scarce bug associated with creeping willow in dune slacks as well as on
heaths, and is also known from the county.
The county’s dune systems are also important places for leafhoppers. Two species are
of particular importance. The Nationally Scarce Macrosteles quadripunctulatus is
only known in the south-west from Braunton Burrows and is associated with short
and often quite sparse vegetation where it is believed to feed on grasses. The Red
Data Book Psammotettix maritimus (Perris) is a southern European species, so far
only known in Britain from Dawlish Warren. It has been found amongst sparse grassy
vegetation with much bare sand, at the seaward edge of the dunes, and is possibly
associated with marram.
The final coastal habitat of importance for bugs is saltmarsh. The Red Data Book
plant bug Orthotylus rubidus feeds on glasswort in areas which are not regularly
inundated by the sea. Its British distribution is southern and south-eastern, unlike the
preceding species, but is has been found in Devon. There is also a Nationally Scarce
hopper Oliarus leporinus in the county’s saltmarshes.
Leaving the coasts, the single most important habitat of inland Devon for bugs is
undoubtedly the enclosed woodlands. Devon has the distinction of still supporting a
number of species which require open flowery conditions within woodland and which
were formerly favoured by active coppice cutting. These are now more dependent on
the poor growth of the moorland fringe oak woods, where open canopy conditions
reflect the acid soils more than disturbance. The Nationally Scarce shield bug Sehirus
biguttatus feeds on the seeds of common cow-wheat and is found amongst the leaf
litter around the bases of the plants in open sunny areas. It has been found in
Hembury Woods and the Heddon Valley oak woods. The Nationally Scarce spurge
bug Dicranocephalus medius is also found at Hembury Woods, associated with wood
spurge where it grows in profusion in warm sheltered open areas. These situations are
also where the Nationally Scarce spurge lace bug Oncochila simplex may be found. A
more elusive species is the Red Data Book Taphropeltus limbatus which lives in ants
nests in woodlands and was reported in the Meavy Valley and near Dunsford many
years ago. Another woodland bug, the leafhopper Platymetopius undatus, was
reported from Bickleigh Vale many years ago and is now thought to be extinct
nationally.
Ancient wood pastures are little studied in the county and may well prove to have
significant interest for bugs. A taster is Loricula ruficeps discovered new to Britain by
Pete Kirby a few years ago now in Whiddon Park – this record has yet to be formally
published. This is a small predatory bug which lives on tree trunks and branches,
amongst epiphytic lichens and fruit bodies of wood–decay fungi. Ancient wood
pastures tend to be especially rich in epiphytes and fungi and so it should be no
surprise that these features have special invertebrates associated with them.
Wood pastures and orchards are very similar in composition – open-grown trees in
grassland. They are similar too in having interesting species living on their trunks and
boughs. Physatocheila smreczynskii (Nationally Scarce) is a lace bug similar in
appearance to the widespread P. dumetorum which is found on hawthorn and
blackthorn. In contrast though, it is found on old lichen-covered apple trees in old
orchards and on crab apple in woodlands. I have found it in Cornwall and look
forward to searching for it in Devon’s orchards.
Although not good for Nationally Scarce or Red Data Book bugs, the high moors do
have their specialities. Wetland habitats are especially of interest in the context of the
south-west. Dartmoor is the only area in the region with the shore bug Saldula
scotica, which lives amongst the shingle and boulders at the margins of upland fast
streams. Here also may be found other northern or upland species such as
Cryptostemma alienum and Saldula c-album. I have found the latter quite widely in
the Dartmoor and Exmoor wooded valleys. Exmoor merits special mention for the
water bug Glaenocorisa propinqua, a species of deep upland pools, swimming near
the surface and straining planktonic organisms after dark, and retreating to the bottom
during the day. This is a relict northern and upland species confined in the south to
Exmoor.
A few species are wetland specialities. Adelphocoris seticornis (Nationally Scarce) is
mainly associated with tall vegetation in wet situations, such as ditch margins in
grazing levels and water meadows, where it feeds especially on the unripe fruits of
bird’s-foot trefoils, meadow vetchling and tufted vetch. Adelphocoris ticinensis
(Nationally Scarce) is a species of fens and marshes where it feeds on large bird’sfoot trefoil and marsh pea. Capsodes flavomarginatus (Nationally Scarce) is usually
found on large bird’s-foot trefoil in damp woodland rides over much of its GB range
but occurs in more open marshes in the west. The Nationally Scarce shield bug
Eurydema dominulus is similarly a woodland species in the south-east but the old
Devon record may have come from an open marsh – it feeds on crucifers, especially
lady’s smock Cadamine pratensis, the nymphs favouring the developing fruits. In the
south-east it is associated with open areas in woodlands – rides, clearings and
especially recently cut-over coppice.
Two final species will be more of a challenge to find. Scolopostethus pictus
(Nationally Scarce) lives in accumulations of dry plant material, presumably feeding
on small fungi. Typical wild sites are ant nests and reed litter, while it also occurs in
haystacks, thatch, etc. Pygolampis bidentata (RDBK) is a ground-living bug, found
amongst stones and grass roots. It has only ever been found at three UK sites:
Bridgnorth (Shropshire), the New Forest and Totnes. The Totnes record was from
sweeping in “a damp place”.
Acknowledgments
We would like to thank Bernard Nau, for permission to use his photographs
(Copyright © B.S.Nau 2003).
Keith Alexander
59 Sweetbrier Lane, Heavitree, Exeter EX1 3AQ