True Dragonflies
- Some images
Short description
- Dragonflies are flying insects of the Suborder ANISOPTERA in the order Odonata. They are similar to damselflies, which constitute the other odonatan suborder
General biology of dragonflies and damselflies
- We provides no overview of the general biology of dragonflies, but three essential facts help understand most of their habits:
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- they are amphibiotic, so eggs and larvae develop in water, while adults live on land and in the air;
- they are obligate carnivores, so all species hunt, both as larva and adult;
- their reproduction is unique.
- Because the male holds the female behind her head with the tip of his abdomen, direct sperm transfer between the genitalia (also located at the tip of the abdomen) is impossible. Sperm is therefore transferred indirectly via secondary genitalia at the base of the male's abdomen.
- Suborder ANISOPTERA Selys, 1854
- This suborder is regarded as True Dragonflies. The suborder Zygopera is called Damselflies
Distribution Worldwide
- Worldwide about ten families are distinguished
Distribution in Africa and surrounding Islands
- Half of families are found in Africa.
- Six in South Africa
- One genus endemic ro South Africa
General identification features
- Dragonflies are heavy-bodied, strong-flying insects that hold their wings horizontally both in flight and at rest.
- Many adult dragonflies have brilliant iridescent or metallic colours produced by structural coloration, making them conspicuous in flight. Their overall coloration is often a combination of yellow, red, brown, and black pigments.
- Wings are generally clear, apart from the dark veins and pterostigmata. Many genera have areas of colour on the wings: for example, Groundlings (Brachythemis) have brown bands on all four wings, while some Scarlets (Crocothemis) and Dropwings (Trithemis) have bright orange patches at the wing bases. Some have translucent, pale yellow wings
- Eyes are large and touch each other, with the exception of the Gomphidae.
- In rest the wings are held wide, often even pressed down. Only very teneral individuals fold the wings above abdomen
Habitat
- Dragonflies live on every continent except Antarctica.
- Occupy a considerable variety of habitats, but many species, and some families, have their own specific environmental requirements. Some species prefer flowing waters, while others prefer standing water. Some species live in temporary water pools and are capable of tolerating changes in water level, desiccation, and the resulting variations in temperature, but some genera such as Sympetrum (darters) have eggs and larvae that can resist drought and are stimulated to grow rapidly in warm, shallow pools, also often benefiting from the absence of predators there
- Vegetation and its characteristics including submerged, floating, emergent, or waterside are also important. Adults may require emergent or waterside plants to use as perches; others may need specific submerged or floating plants on which to lay eggs. Requirements may be highly specific
Behaviour:
- Many dragonflies, particularly males, are territorial. Some defend a territory against others of their own species, some against other species of dragonfly and a few against insects in unrelated groups.
- A particular perch may give a dragonfly a good view over an insect-rich feeding ground, and males jostles other dragonflies to maintain the right to alight there
- Defending a breeding territory is fairly common among male dragonflies, especially among species that congregate around ponds in large numbers
Southern African genera
Please click Here for the complete list of genera species visible in southern African