South Gower Cliffs - Gower - page 98

Notable beetles on the cliffs include three species in which the larvae feed and develop in the nests of
bees and wasps, the rare Metoecus paradoxus , Meloe prescarabaeus and the oil beetle Meloe violaceous ,
which has been recorded from Slade. The oil beetle is so named because it can give off a strong-smelling
liquid from a gland behind the head. In contrast to the other two species M. prescarabaeus is widespread
ontheGowercoastandlarvaewereabundantduring2003and2004.TheMeloidaefamilyaresoft-bodied
beetles with a narrow neck and often have short wing cases, which makes them relatively easy to identify
inthefield.Theyareofparticularinterestbecauseoftheircomplexlifecycles,theearlystagesoftheBrit-
ish species being parasites of solitary bees. In spring the female beetles lay several thousand eggs in the
soil, in a number of different batches. The eggs soon hatch into tiny louse-like larvae, with strong claws,
thatcrawlupontodandelionheadsandotherspringflowersandawaitthearrivalofthehostinsects.Only
a small proportion find the right host and the unsuccessful larvae die. The successful ones are carried to
the bee's nest, where they detach themselves and find an egg to eat. After this the larva feeds on the bee's
foodreservesofpollenandnectar,undergoingaseriesofmoultsbeforeemergingasamatureadult.Other
beetles found in the area include the bloody-nosed beetle Timarcha tenebricosa , which like the oil beetle
also produces a fluid, the burying beetle Necrophorus humator , which buries carrion for its larvae to feed
on, and the minotaur beetle Typhaeus typhoeus , which uses rabbit and sheep dung for its larvae.
Perhapsthemostprominentbeetleofthecliffgrasslands,certainlyduringthelateeveninginJuneand
July, is the glow-worm Lampyris noctiluca . Female glow-worms often appear a few days before the first
male.Thefemaleusuallybeginstoglowsoonafterdusk,whichduringtheseasonisusuallybetween2200
and 2300 hrs. The display continues for two or three hours and if after that time the female has not been
successful in attracting a mate she will stop glowing, retreat into the grass and return for another attempt
the following night. The larvae feed almost exclusively on slugs and snails. Recent research has revealed
that during the day the female tries to escape the light by using the abandoned burrow of a solitary bee,
so it is important to conserve such bees if glow-worms are to survive in the peninsula. Dillwyn recorded
in 1829 that glow-worms were 'not uncommon on dry hedgebanks; but the light is not so brilliant as it
is on chalky soils, nor have I observed the small light in the males which is always sufficiently obvious
about Dover [where he started his interest in natural history]. I placed some of these insects in oxygen,
and could not detect any increase in their brilliancy.' There are only isolated reports of glow-worms on
theGowercliffsandelsewhere,andmoreworkisneededtoestablishthesizeandlocationofpopulations.
Indeed there is scope for further survey work on all the coastal invertebrates present in Gower, and in
many cases more information on the life histories of species is also needed, in order that effective man-
agementstrategiescanbedeveloped.Evennownaturalistsareonlybeginningtoglimpsetheintricateweb
that binds together invertebrates such as oil beetles, solitary mining bees, cuckoo bees and glow-worms,
and there are undoubtedly more connections that need to be understood before the survival of these spe-
cies can be assured.
REPTILES
The warm south-facing cliff slopes are also ideal for reptiles, and common lizard Lacerta vivipara , grass
snake Natrix natrix , slow-worm Anguis fragilis and adder Vipera berus can all be found along the coast.
Addersfeedmostlyonrodentsandlizards,strikingtheirpreytoinjectvenomandthenfollowingthescent
trail of the dying animal. They are most easily seen on dry cloudy days, when they need to bask to raise
their body temperature. On a very hot and sunny day they might bask in the morning or evening sun, but
theyremainintheshadeduringthemiddleoftheday.Elsewhereaddershavedeclinedinabundancesince
the1960s,mainlybecauseofhabitatlosses,butthepopulationsinGowerhaveremainedrelativelystrong.
To date there have been no detailed studies of reptiles on coastal cliffs, but as they require dense ground