Andrew Lucas wrote:
Much of my natural
history recording in recent years has been devoted to SN6802, my home 1km
square, which includes some of Clydach and a small part of the Cwm Clydach RSPB
reserve. In the last week, my efforts have been
rewarded with a couple of nice finds
Phasia hemiptera is an impressive tachinid fly that I found
flying around hemp agrimony in the beer garden of the New Inn pub, Clydach on 8
August 2014. Its size, and the reddish
orange hairs on the side of the thorax, distinguishes it from other species in
the genus. I caught a female, but the
males are even more striking, with boldly metallic blue and white patterned
wings. In the larval stage, the insect
is parasitic on shieldbugs. The female
lays her eggs on a bug, which then hatch and eat the insect from the inside
out!
SEWBReC have
advised that this is the first record they have received for P.
hemiptera in the City and County of Swansea, although its presence is no
great surprise, as it has been found a number of times in the Llanelli
area. The species has been recorded as
far north as Inverness, but most records come from southern England
Rhingia rostrata is a woodland hoverfly, similar to the much
more common R. campestris. It is
distinguished (Stubbs & Falk 2002) by the uniformly light side to the
abdomen, whilst R. campestris has a dark line along the abdomen edge. But it’s a much classier insect than R. campestris, with a bluish thorax and
lighter abdomen that is obvious even to the naked eye. I came across several feeding on hogweed
along the footpath near the car park at Cwm Clydach RSPB reserve, again on 8
August 2014.. Rhingia hoverflies are
unusual amongst the British Syrphidae, in having long mouthparts tucked away
underneath the rostrum that projects from the head. This allows them to feed on deep flowers that
are inaccessible to most hoverfly species.
The larval stage of this species is a mystery, although it is thought to
feed on rotting material or carrion, as R.
campestris is known to use cattle dung.
SEWBReC and the NBN
gateway (https://data.nbn.org.uk/) have R. rostrata only recorded once
previously in Glamorgan, near Nicholaston Woods in 2009, although the hoverfly
recording scheme (http://www.hoverfly.org.uk/portal.php) has records from SS69 in 2009, and ST09 in
2001. It has a similar distribution to P. hemiptera, with the northern edge of
its distribution lying in the Lake District
References
Stubbs, A.E. & Falk, S.J. (2002) British Hoverflies. An
illustrated identification guide. BENHS.
