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Coenagrion armatum (Charpentier) Norfolk damselfly
Description The male of C. armaturn is almost entirely black with dull greyish blue
coloration on several segments at either extremity of the dorsal surface of the
abdomen, though not segment 10 which is black. Unlike other species of this
genus, there are no antehumeral stripes on the male thorax, although four
spots may occur. The black marking on segment 2 of the abdomen typically
has a lateral, sometimes isolated, arm extending along either side of the
segment. The most notable feature of male C. armaturn, however, is the anal
appendages, in which the inferior pair of appendages is very elongated.
Females are mostly dull black with greenish markings, but they are unique in
that the black on the dorsal surface of segment 2 does not extend the whole
length of the segment — the anterior half is greenish. Of the female, Porritt
(1910) wrote 'when flying in the sun, the mature insect is a very striking Agrion
and cannot be mistaken for any other British species; the green on the front
and posterior segments of the abdomen shines like emeralds...'.
Habitat and C. armatum favours mesotrophic ponds and ditches with an abundance of
breeding biology common reed and sedges, amongst which they fly Females have been
observed to oviposit into the tissues of frogbit.
Flight periods The flight period in Britain is not well recorded, but is likely to have been from
Status and distribution
European and world
distribution
late May to at least mid-July
C. armaturn was first recorded in Britain at Stalham, Norfolk in May 1903 by
Balfour-Browne (Balfour-Browne 1904). A Mr Edelston subsequently informed
Balfour-Browne that he had found it there in 1902. The site, at Sutton Broad,
Stalham, appears to have been the stronghold of the species, it being seen
there regularly until the 1950s. Porritt (1912) recorded C. armatum 'on both
Sutton and Stalham Broads, and over a fairly wide area'. A few C. armatum of
both sexes were also recorded from a ditch at Hickling Broad by T A Coward
on 24 May 1919. Cynthia Longfield (1954) wrote that A E Gardner had
reported that C. armatum still occurred in fair numbers, but she went on to say
that 'it is, however, very disturbing that the latter's restricted habitat is rapidly
drying out and the nature of the vegetation changing completely.. and it is
sincerely to be hoped that some remedy will be found in time to save the
extinction of C. armatum'. It was not, and the species was last reported in
1957 (Hammond 1977). Surveys by the NCC in the mid-1970s found the area
of its former site to be thoroughly overgrown with common reed, sallow and
alder carr, and mostly dried up.
C. armaturn is a boreal species which occurs from the Baltic area eastwards
through Poland and Russia to Mongolia. It was last recorded in The
Netherlands in 1924 (Geijskes & van Tol 1983), and was lost from sites in
northern Germany in the mid-1970s owing to the drying up of its habitat
(Schmidt 1978).
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