Sympetrum vulgatum/striolatum
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This is a study of the differences between two very similar Sympetrum species, found in most of Europe.
A large amount of pictures has been taken in the period between 6th of September '03 and 17th of October '06,
and are used to investigate the differences between the two species. All the pictures are taken in Svanemosen
near Kolding, Denmark, except where noticed otherwise.
It has not been clear if the subspecies S. striolatum nigrescens is present in Denmark,
but I've specified several of the pictures to show the nigrescens. Any coments to my
photographic study here is most welcome, both regarding the identifications I've made, and
my comments on differences between the two species S. vulgatum and S. striolatum.
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Top: Oviposition in flight of tandem Sympetrum vulgatum.
Left: Sympetrum striolatum male in flight over small pond.
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Difference in black patch on frons.
Top-left: pic-a1, 10/09-04: Sympetrum vulgatum, female (pic-d3, i5)
Top-right: pic-a2, 19/08-06: S. striolatum, female (pic-b2, i8)
Bottom-left: pic-a3, 08/08-04: S. vulgatum, male.
Bottom-right: pic-a4, 27/07-05: S. striolatum nigrescens, teneral female
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Sympetrum vulgatum and Sympetrum striolatum are two very similar species, making
identification difficult out in the field. Sympetrum striolatum may occur
in the form or subspecies nigrescens, which complicate the matter even further.
The species can be seperated by the differences in the males secondary genitalia, and in the females vulvar scale. This is hard to do
with the males, but the females vulvar scale can easily be seen in a side view.
The species (both males and females) can be seperated by the black area at the base of frons, bordering the eyes.
On S. vulgatum, this black area extends down along the eyes. On S. striolatum it does not extend as far down
, but end close to the place where the eyes colour-transition is (where the smaller lower and larger upper ommatidia meet).
The legs on both species are black, with bright tan lines along the femur and tibia. On S. striolatum, the lines on the femora are thinner than on S. vulgatum,
but generally the thickness of the lines varies on both species. The lines darken with age, especially on the males.
On S. vulgatum males, these lines tend to become red with age, first brigt red, later dark red.
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The males differ in the shape of the abdomen, when seen from the back. The abdomen on S. vulgatum males
are slightly clubbed, the 7th segment widest and most narrow at 3rd and 4th segment. The abdomen on
S. striolatum males are more evenly wide along the length.
There is no significant difference, between the shape of the female abdomen of the two species.
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Vulvar scale on females. S. vulgatum has a vulvar scale more pointed and perpendicular to the abdomen.
Left: pic-b1, 02/09-06: Sympetrum vulgatum (pic-i1)
Right: pic-b2, 19/08-06: S. striolatum (pic-a2, i8)
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Male secondary genitalia, seen from right side.
Top-left: pic-c1, 28/08-04: Sympetrum vulgatum, through right rear wing.
Top-right: pic-c2, 09/10-04: S. striolatum, through right rear wing (pic-f4, g6)
Bottom-left: pic-c3, 05/10-06: S. vulgatum, through right rear wing (pic-d5, g7)
Bottom-right: pic-c4, 16/09-06: S. striolatum, from a low position (pic-d6, g12)
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Both species are yellow in colour when immature, and there is little difference between males and females. The males abdomen change
to red while maturing, S. vulgatum becoming bright red, and S. striolatum attaining a more orange hue.
The abdomen of the females darkens on the sides from yellow to brown, but they may develope red on the top of the abdomen. Old females
may become dark brown all over. Less difference is seen between the females of the two species, compared to the males.
The thorax matures to the a dark brown colour, and it seems like S. striolatum retains a slight yellow hue on
the lower part of the sides. Generally the individuals varies much in colour for the two species, and they may appear darker
in cool weather than on sunny warm days.
The striolatum variant S. striolatum nigrescens, are generally darker, both on thorax and on the sides of the abdomen. The dark patch on the
frons in front of the eyes, are intermediate between S. striolatum and S. vulgatum. I only have a few pictures I suspect is showing nigrescens
, but it is not clear if this subspecies is present in Denamark. Nearly all pictures here are from Svanemosen in Kolding.
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The behaviour of the two species is quite identical. The males of S. striolatum are more often seen though, in sustained flight over the water.
An interesting observation is that in the start of the flight periods, which seem about the same for the two species,
males of S. vulgatum is more often seen than the females, away from the water. The opposite is seen with S. striolatum. This observation done by
others, are also confirmed through my rather random photos of the species.
Oviposition is done in tandem above the water, or above the wet ground close to the pond. Sympetrum vulgatum are
often seen ovipositing above floating spagnum, whereas S. striolatum should prefer open water.
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Legs on the right side of thorax. Notice how the bright area on the femur of the front leg, are more extensive
on S. vulgatum.
Top-left: pic-d1, 07/09-06: Sympetrum vulgatum, female.
Top-right: pic-d2, 14/08-04, S. striolatum nigrescens, female (pic-i12)
Middle-Left: pic-d3, 10/09-04: S. vulgatum, female (pic-a1, i5)
Middle-right: pic-d4, 19/08-06: S. striolatum, female (pic-i14)
Bottom-left: pic-d5, 05/10-06, S. vulgatum, male (pic-c3, g7)
Bottom-right: pic-d6, 16/09-06: S. striolatum, male (pic-c4, g12)
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Mating wheels of the two species.
Top: pic-e1, 13/09-03: Sympetrum vulgatum.
Bottom: pic-e2, 08/10-05: S. striolatum.
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Sympetrum vulgatum, males
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Sympetrum striolatum, males
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pic-f1, 09/09-06
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pic-f2, 09/10-04
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pic-f3, 13/09-03
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pic-f4, 09/10-04 (pic-c2, g6)
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pic-f5, 06/09-03
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pic-f6, 23/09-06
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pic-f7, 15/10-05
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pic-f8, 10/10-04
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pic-f9, 08/08-04
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pic-f10, 13/09-03, S. striolatum nigrescens
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Sympetrum vulgatum, males
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Sympetrum striolatum, males
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pic-g1, 17/09-05
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pic-g2, 25/09-06
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pic-g3, 22/08-04
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pic-g4, 28/08-04
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pic-g5, 04/09-04
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pic-g6, 09/10-04 (pic-c2, f4)
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pic-g7, 05/10-06 (pic-c3, d5)
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pic-g8, 10/10-04
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pic-g9, 21/08-04
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pic-g10, 22/08-04
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pic-g11, 01/09-05
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pic-g12, 16/09-06 (pic-c4, d6)
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Sympetrum vulgatum, females
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Sympetrum striolatum, females
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pic-h1, 04/10-06
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pic-h2, 08/10-05 (pic-i2)
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pic-h3, 17/09-05
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pic-h4, 10/10-04
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pic-h5, 12/09-06 (pic-i11)
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pic-h6, 17/10-06
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pic-h7, 10/10-04
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pic-h8, 09/09-06
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pic-h9, 28/08-04 (pic-i9)
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pic-h10, 05/10-06
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pic-h11, 07/08-05
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pic-h12, 12/09-06 (pic-i6)
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Sympetrum vulgatum, females
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Sympetrum striolatum, females
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pic-i1, 02/09-06
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pic-i2, 08/10-05 (pic-h2)
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pic-i3, 21/09-06
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pic-i4, 14/09-06
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pic-i5, 10/09-04 (pic-a1, d3)
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pic-i6, 12/09-06 (pic-h12)
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pic-i7, 05/09-06
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pic-i8, 19/08-06 (pic-a2, b2)
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pic-i9, 28/08-04 (pic-h9)
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pic-i10, 16/08-06
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pic-i11, 12/09-06 (pic-h5)
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pic-i12, 14/08-04, nigrescens (pic-d2)
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pic-i13, 01/09-05
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pic-i14, 19/08-06, nigrescens (pic-d4)
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