Dragonflies, an amazing and unique insect is from the order Odonata and the Anisoptera suborder. The attractive characteristic of this creature is the multifaceted large eyes, an elongated body and four transparent and strong wings, with colored markings. They are often misunderstood as a damselfly, which has a similar structure, but the latter has a slightly lower build. These agile flyers have a beautiful metallic or iridescent color produced by the coloration of the structure, evolving them as a conspicuous insect during flight. The special feature of a dragonfly is its eyes that have more than 24,000 ommatidia (Wiki_ “The compound eyes of arthropods like insects, crustaceans and millipedes are composed of units called ommatidia (singular: ommatidium). An Omatidium contains a cluster of photoreceptor cells surrounded by support cells and pigment cells”).
Dragonflies of any species or genus are basically brutal predators, both in the adult form as well as in the larval stage, at which they are referred as naiads or nymphs. In a dragonfly’s life, many years are spent as a larva in the freshwater habitat. The adult form in the flying stage last for only a few weeks or days. They are renowned as agile and fast fliers that migrate across the sea and oceans, but their actual habitat is away from the water body.
Dragonflies are widely spread, and commonly occur on every continent, except the continent of Antarctica. Some species and genera of dragonflies are seen across continents. For example, the species Blue-Eyed Darner, biologically known as Rhionaeschna Multicolor is widely spread across northern parts of America. It also occurs in Central America, stretching from Newfoundland in the north to the south of Bahia Blanca situated in Argentina, throughout Europe to Asia, Middle East and North Africa. The world’s most common and widespread species of dragonfly is the globe skimmer, Pantala Flavescens. This species is cosmopolitan, and hence it occurs in all the continents, especially in the warmer areas. Most of the species of Anisoptera are tropical, and only a very few are seen in the temperate regions. The dragonfly can inhabit mountainous to sea level regions, but the diversity in species decreases along with the altitude. The Aeshnids and Libellulid dragonflies are seen in the desert pool areas, such as the desert of Mojave, where they prefer living in shades, at a temperature of 18 to 45 degree Celsius. They also have the ability to survive even when their body temperature rises above the normal insect’s temperature, especially those found in the cooler regions. Generally, the dragonflies become limited in higher altitude areas. Hence, you will not find much species in Iceland. These dragonflies do not inhabit such regions, but strong winds can occasionally sweep them there, like the species Hemianax Ephippiger, which is actually an inhabitant of North Africa, but is found in Iceland. The other place like Kamchatka, where the lakes and other water bodies have very low temperature, is a difficult habitat for dragonflies to survive, but still some species like Somatochlora Arctica and Aeshna Subarctica can be found in this region.
Types of Dragonflies
An estimate of 3012 dragonfly species had been described until 2010. These species have been classified into 11 families comprising about 348 genera. They are mainly distributed into three super-families, the first being.
This is a super-family consisting of dragonflies. It consists of five dragonfly families comprising of the “hawkers,” out of which, one family has no existing species. The five families of this super-family are-:
This family belongs to the super family Aeshnoidea, and consists of dragonflies named as ‘Petal tails’. It is believed to be the most ancient species of the extant dragonflies present in this family, that also have fossils dated back to the era of the dinosaurs around 150 million years ago. Out of the 11 species present in the present Petaluridae Family, the largest dragonfly is the Australian Petalura Ingentissima that has a wingspan of over 160mm, and the length of the body is around 100mm. Other popular species found in Australia are Petalura Gigantea, which is commonly referred as ‘giant dragonfly’. Two other species are commonly found in the United States. This family consists of five genera, namely-:
The commonly referred hawkers or darner belongs to the Aeshnidae family, and is most widely spread in the North America. It is the largest dragonfly found in Europe and North America, and is considered as one of the largest dragonflies on the earth. This family is also well-known for comprising the fastest flying species of dragonflies. There are numerous genera in this family, few of them are-:
This family member, belonging to the Odonata order, is commonly known as ‘Clubtail dragonfly’. It is a big family that consists of 900 species and 90 genera. The dragonflies are named so, due to their club-like expanding abdominal segments 7 through 9. But this peculiarity is absent in the female Clubtail and other species in the same family. This family also consists of numerous genera; a few of them are-:
The Austropetaliidae family of dragonflies is small and consists of only 4 genera. The dragonflies of this family are commonly seen in Australia and Chile. The genera are-:
- Phyllopetalia .
Cordulegastroidea is the second super-family consisting of dragonflies. This super family consists of three families, namely:
The Cordulegastridae family of dragonflies belongs to the Anisoptera Suborder. The dragonflies of this family are commonly referred to as ‘Spiketails’. Other vernacular terms used to refer this creature are ‘Flying Adder’ and ‘Biddie’. These dragonflies have large black or brown bodies with patches of yellow shade. Their common habitat is clear, small woodland streams, where they fly about 30 -70 cm over the water. This small family has only four genera, namely,
- Neopetalia Punctata
The family Neopetaliidae consists of the only family member, Neopetalia Punctata dragonfly. This species occurs commonly in Chile and Argentina. The only genus of this family is Neopetalia.
Chlorogomphidae – Photo by: Daderot
The Chlorogomphidae family is a small group of dragonflies, belonging to the Anisoptera suborder. This small family consists of only four genera, namely,
This is the last and the third super-family consisting of four dragonfly families. Those families are-:
This Corduliidae family of insects consists of green-eyed skimmers or emerald dragonflies. The body of the dragonfly of this family is usually dark brown or black, and some areas also have metallic yellow or green patches. The name, Emerald or Green-Eyed are acquired due to the large, emerald like, green-colored eyes they possess. The larvae of this dragonfly are usually hairy-looking, black and semi-aquatic in nature.
Members of this family include the Baskettails, Emeralds, River Cruisers, Sundragons, Shadow dragons, and Boghaunters. They are very common, and distributed nearly worldwide, but a few individual species are very rare. For example, the species Hine’s emerald dragonfly, biologically known as Somatochlora Hineana is considered as an endangered species in the America.
This family includes four sub-families, namely:
Some other genera are-:
- Cordulia – American emeralds
- Dorocordulia – little emeralds
- Helocordulia – Sundragons
- Epitheca – baskettails
- Neurocordulia – shadowdragons
- Somatochlora– striped emeralds
- Williamsonia – Boghaunters
The Libellulidae is the world’s largest family, consisting of the perchers or skimmers and the other related species of dragonfly. The subfamily Corduliidae of Corduliinae and Macromiinae subfamily of Macromiidae are sometimes considered as the member of this family. The total strength of this family is more than 1000 species. Hence, the most commonly seen dragonflies may be from this family, and it is widely distributed across the planet. Some of the genus in this family are-:
The dragonfly family Macromiidae consists of the dragonfly species, commonly referred as ‘Skimmers’ or ‘Cruisers’. They are usually seen flying over the water bodies through the middle. They have a similar structure to that of the Aeshnidae, but the eyes of Macromiidae Dragonflies are green in color, and can be seen on the top part of the head. Traditionally, the Macromiinae or the Macromiidae has been included in the Corduliidae, as a subfamily. They are around 125 species classified into three genera. Those three genera are-:
The Synthemistidae family is well-known for the dragonflies that are commonly referred as ‘Tigertails’ or ‘Southern Emeralds’. It consists of 43 species and seven genera. The dragonflies of this family have similarity with the Gomphid or the Corduliid dragonflies. Sometimes, this family is included in the Corduliidae as a sub-family. It is considered to be one of the ancient families of dragonfly that occurs commonly in New Guinea and Australia. The species of this family are basically small sized, and have narrow or small abdomen. The larval stages of these dragonflies are usually bottom-dwellers in nature, and have the capability to survive in drought conditions by hiding themselves deeply. They are mostly found in marshy places and around fast moving streams. Some of the genera of this family are-:
Decreasing Dragonfly Population
Most dragonflies inhabit the temperate and tropical regions. Though, till recently, they were not considered as an endangered species, recent studies reveal the quick rate of depletion of the dragonfly numbers. The main reasons considered for their decline are the deforestation of rainforest habitats, drying up of freshwater bodies like streams, pools and lakes, forest clearance and pollution. If this continues, their habitat will be wiped out, and they will become an extinct species soon.