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Status and distribution
Pyrrhosoma nymphula (Sulzer) Lar ge r ed damselfly
Description This is one of the two red damselflies found in Britain, and the only one to
occur in Ireland. It is much the commoner of the two species and can readily
be distinguished from Ceriagnon tenellum, the other red damselily, by the
prominent red or yellow antehumeral stripes, and black legs. It is also a much
more robust damselfly In males, the deep red and black coloration of the
thorax and abdomen makes the species an attractive sight. The eyes of both
sexes are also red, duller in females. The female occurs in three colour forms:
in one the abdomen is mainly black, and the other two vary in the extent of
black on the red abdomen.
European and world
distribution
Habitat P. nymphula is found in a very wide range of habitats in Britain and Ireland,
including acid bogs, the quieter stretches of quite fast streams and rivers, and
also in well-vegetated ponds, canals and ditches. It can occur in slightly
brackish water (Long-field 1937).
Breeding biology The adults of P, nymphula are very territorial. Their highest steady density is
about 30 per 100 m of water's edge. Copulation takes about 15 minutes and
the eggs are inserted into the tissues of submerged plants or the underside of
floating leaves of plants, such as pondweed, with the male in tandem. The
larvae, which live amongst roots and bottom debris, usually take two years to
develop, but can take one year, or, at high larval densities, three years (Macan
1974). It is one of the few species known to be territorial in the larval stage.
Successful territorial behaviour results in larger larvae and hence greater
reproductive success as adults (Harvey & Corbet 1985).
Flight periods P. nymphula has a synchronised emergence and is one of the first dragonflies
on the wing, from late April onwards in south-western counties. There is a
second, smaller, unsynchronised emergence in the summer, and a few adults
may be on the wing until early September. Adults take 6-15 days to mature
(Corbet & Harvey 1989). Reproductively mature adults may then live about a
week on average, some surviving 35-45 days.
In some small peat pools and acid seepages in upland areas, P nymphula may
be the only dragonfly present. Elsewhere, it can be found with almost all our
other dragonfly species, including C. tenellum in southern England and Wales.
P nymphula is widespread as a breeding species in Britain and Ireland,
occurring as far north as the Orkneys. However, in some chalk counties,
notably Wiltshire, it is a scarce species and is absent from many sites which
support other dragonflies. It has declined in the intensively cultivated areas of
eastern England, such as the Fens, except where there is very clean,
unpolluted water.
Pyrrhosoma is one of the few genera that is confined to the Palaearctic region.
nymphula is widespread throughout most of Europe, although thinning out
towards the south in some Mediterranean countries, and absent from several
larger Mediterranean islands. Its range extends into Asia, and Morocco in
North Africa.
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