Sympetrum sanguineum (Muller. 1764) Ruddy Darter
The males of this average-sized darter can. with some practice, be distinguished in the
field from males of Sympetrum striolatum by the shape of the abdomen. In S. striolatum
the abdomen is more-or-less parallel sided, whereas in S. sanguineum it is narrowed in
the region of segments 3 to 5. giving a club-shaped appearance. In addition, the
abdomen of S. sanguineum is noticeably shorter (relative to wing-span) than that of 5.
striolatum, and is generally more brightly and uniformly red in colouration than even
fully mature males of S. striolatum. A useful back-up character is that S. sanguineum (in
both sexes) have completely black legs, whereas S. striolatum usually have a pale
longitudinal stripe along each leg. The females of both species are generally light
yellowish brown in colour, but acquire some of the reddish hue of the males with
advancing age.
The males are strongly territorial at their breeding sites, selecting well spaced-out
perches from which they periodically fly in pursuit of food, females, or intruding males.
On one occasion I observed a male of this species repeatedly 'buzz' and drive off a male
of Aeshna mixta. Pairs mate in the characteristic 'wheel' position common to all
dragonflies, frequently remaining paired for some considerable time among marginal
vegetation. Egg-laying takes place in tandem, with the male flying low over water (or
emergent vegetation such as Sea Club-rush), with an undulating flight. At the lowest
phase of the undulations, the female's abdomen 'smacks' the water-surface, and eggs
are released freely into it. Usually richly vegetated sites are chosen for breeding. Indeed,
ovipositing was observed over a dyke entirely choked with Sea Club-rush at Old Hall
Marshes. In Essex. S. sanguineum breeds in a variety of habitats, such as (often brackish)
coastal and estuarine dykes, flooded pits (especially where these are shallow and richly
vegetated with Reed-mace and other emergent vegetation), forest lakes, and ponds of
various sizes. The flight-period recorded during the survey ranged from the beginning
of July to mid-September.
Henry Doubleday's (1841) puzzle about the status of Sympetrum basale' is probably a
reference to S. sanguineum (see Appendix B). Doubleday reported the species as having
occurred formerly in profusion, but as having subsequently become scarce. But in his
later (1871) list, he gave the species as common at the gravel pits on Coopersale
Common, though the dates given (September and October) do seem suspiciously late by
comparison with current observations. W. J. Lucas (1900a) reported Harwood on the
breeding of S. sanguineum on 'a part of the Essex coast', and (1900b) as also occurring at
Colchester. Lucas also referred to C. A. Briggs as the source of another record of S.
sanguineum at Leigh. Harwood himself (1903) noted that S. sanguineum seemed to have
'a much more restricted range' than S. striolatum giving St. Osyth as a locality in addition
to Epping. The Campion brothers appear to have observed S. sanguineum only
sporadically in Epping Forest in the years before World War I, but gave evidence of its
breeding there in 1908 (Campion and Campion. 1909). The Campions (Campion and
Campion. 1913) also reported an immature male of the species seen by A. Luvoni at
Westcliff in 1912 - presumably another breeding-record, and the Hope Department of
Entomology at Oxford hold specimens of 5. sanguineum collected by J. W. Yerbury at
Frinton-on-Sea in 1912.
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