Enallagma signatum
| Enallagma signatum | ||||||||||||
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Enallagma signatum , male |
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| Scientific name | ||||||||||||
| Enallagma signatum | ||||||||||||
| Hagen , 1861 |
Enallagma signatum is a species of dragonfly from the family of the slender dragonflies (Coenagrionidae), which is distributed in eastern North America.
features
In contrast to the otherwise predominantly blue-colored species of the cup maiden ( Enallagma ), the body and eye color of the mature male adults is orange. The body length is 28 to 37 millimeters, the abdomen is noticeably slim. The humeral and ante-humeral strips of the thorax are roughly the same width, the dorsal abdomen is predominantly drawn dark, with very narrow light rings at the ends of the abdominal segments. The ninth segment has no drawing and is therefore completely orange and forms a noticeable “tail light”. The cerci are long and distinct. The legs are orange with a black stripe on the outside.
The chest drawing of the females is similar to that of the male, the humeral stripe is somewhat narrower, the tenth abdominal segment is without drawing in contrast to the male, but the ninth has a black triangle on the top. As is not uncommon in the subfamily of the Ischnurinae , the females come in several color variants. There is an orange, androchromic form , somewhat darker than the males, and a yellow-greenish heterochromic form.
The juvenile form of both sexes differs significantly from the mature adults, it is colored in a pale blue, which gradually turns orange.
Similar species
The not yet mature, pale blue colored specimens of Enallagma signatum can easily be confused with Enallagma exulans , but this species has narrower and paler ante-humeral stripes. Mature specimens resemble Enallagma vesperum , but the males of this species are more light yellow with blue posterior abdominal segments. The humeral stripe is much thinner in this species in both sexes, in males it is sometimes not developed at all.
The heterochrome color variants of the females of Ischnura kelicotti and Ischnura verticalis are also orange, but the physique of these pitch dragonflies is more compact and they lack the orange bottom light at the end of the abdomen.
Representatives of the Protoneuridae family can also be colored red or orange and occur in the same habitat as Enallagma signatum , but their abdomen is significantly slimmer and longer, more than twice as long as the wings.
distribution and habitat
The distribution area of Enallagma signatum extends over the east of North America from southern Ontario and Nova Scotia to southern Florida , the western limit of distribution is approximately at the ninetieth degree of longitude . The dragonflies live mainly in ponds, lakes and slowly flowing rivers with a fairly wide choice of habitats and are particularly common where water lilies cover the water surface. The males fly just above the water surface or rest on parts of plants protruding from the water. However, the dragonflies are not bound to the water, but can also stay in the tops of the trees. The females in particular remain at some distance from the water and are difficult to find except in the mating wheel. The pairs usually stay on the edge of the grass and reed mats and, if disturbed, fly onto the open water.
Way of life
In the north of the distribution area the flight time extends from May to October, on the southern edge of the distribution in Texas Enallagma signatum can be found all year round. Unusually for dragonflies, the main activity of the adults does not peak until the late afternoon and lasts into the dark. This means that the maximum activity is only slightly earlier than that of Enallagma vesperum .
The couples lay their eggs in lily pads or algae mats; the female, sometimes even with the attached male, submerges and can stay under water for up to 20 minutes.
swell
literature
- John C. Abbott: Damselflies of Texas: a field guide , University of Texas Press, Austin 2011, ISBN 978-0-292-71449-6 .
- Dennis Paulson: Dragonflies and Damselflies of the West, Princeton Field Guides , Princeton University Press, New Jersey 2000, ISBN 978-0-691-12281-6 .
Individual evidence
- ↑ a b c d e f John C. Abbott: Orange Bluet. In Damselflies of Texas , pp. 158-159.
- ↑ a b c d e f g Dennis Paulson: Orange Bluet. In Dragonflies and Damselflies of the West , pp. 99-100.
- ^ Jill Silsby: Subfamily Ischnurinae (Blue-tailed Damselflies). In Dragonflies of the World . Smithsonian, Washington 2001, ISBN 1-560-98959-9 , pp. 110-112.
