Dragonflise of Sri Lanka

Life Cycle of A Dragonfly

(Drawing: M. Bedjanič)

(1) Mating                                           (2) Egg-laying                         (3-6) larval development

(7) last moulting – emergence             (8) adult insect

The dragonfly has an incomplete metamorphosis, which consists of egg and several larval stages followed directly by the adult phase. Adult phase is characteristic of dragonflies. Dragonfly is an insect whose adult wings are beautifully colored. It can be met along rivers, streams, paddy fields, marshes, pools and lakes almost year round, represent only the shorter phase of their life cycle. They spend most of their lives hidden from human eyes as larvae in the water.

Female adult lays eggs in plant tissue or drops freely into the water. Larvae develop from eggs. The first larva, Nymph 1 is very small. After passing several moults the larva becomes proportionally larger. It’s Nymph 2. Larvae appear as a rough bodied clumsy looking creature with spidery legs and have very little in common with the beautiful winged adults. Both larvae and adults are ravenous and predatory animals. Larva has a modified lower lip, which is folded beneath the head at rest but can grasp prey with lightning speed. They eat small aquatic insects, such as mosquito larvae, and sometimes they feed on smaller fishes.

When the wings of the larva ready to emerge, it climbs out of the water and emerge from the tight larval case. Though it expands its soft wings and flies away, its wings aren’t developed brighter colours. Their attractive colouration develops only after several days of their emergence. Male dragonflies are usually found near aquatic surroundings. As well as feeding, they are very active in finding a female. Female are found on the water when they mate or lay eggs, except these occasions they are fond of living away from the water and feed at forest edges and clearing to avoid contact with the male.

Mating, 

it’s an interesting act in the nature, mating in dragonflies. The primary sexual organs of both male’s and female’s, are situated at the end of the abdomen. They aren’t in direct contact during mating. Underneath the second and third abdominal segment, the male has so called secondary genital organs where sperm is transferred from the abdomen tip. The female, still securely held by the male’s anal appendages, bends her abdomen and genitalia to the secondary genitalia of the male and the partners are joined. This beautiful heart-shaped figure is called a “wheel” or “copula”.

Dragonflise of Sri Lanka

Dragonflies of Sri Lanka

Classification

• Kingdom          Animalia
• Phylum            Arthropoda
• Class                Insecta
• Order              Odonata

We have a large amount of dragonfly species in Sri Lanka. Among them, some are common to Asia and some of them are endemic species. There are 117 dragonfly species and ,out of them 53 species can be found nowhere else. Dragonflies can be found throughout the year all over the country.

A dragonfly is an insect belonging to the order Odonata. Dragonfly (Order Odonata) has 3 suborders and 2 suborders are present in Sri Lanka.  Damselflies belong to the suborder Zygoptera, Dragonflies belong to the suborder Anisoptera. It is characterized by large multifaceted eyes, two pairs of strong transparent wings, and an elongated body. Dragonflies are similar to damselflies, but the adults can be differentiated by the fact that the wings of most dragonflies are held away from, and perpendicular to the body when at rest. Dragonflies possess six legs (like any other insect), but most of them cannot walk well. Dragonflies are some of the fastest insects in the world.

Families of dragonflies

 

• Aeshnidae
• Austropetaliidae
• Chlorogomphidae
• Cordulegastridae
• Corduliidae
• Libellulidae
• Neopetaliidae
• Petaluridae
• Synthemistidae

Dragonflies are valuable predators. They eat mosquitoes, and other small insects like flies, bees, ants, and very rarely butterflies. They are usually found around lakes, ponds, streams and wetlands. That because of their larvae, known as "nymphs", are aquatic.

Blue Oak Leaf

         Blue Oak Leaf

 This is one of the interesting butterflies in the butterfly world. It’s because of its amazing wings, which are similar to a dry leaf both in shape and color. It is highly difficult to identify in low lit rain forest. They take to wings with the least disturbance, and splashing blue colors of the upper side of wings are really amazing. When they settle in a branch, it may be very difficult to you to trace this butterfly, though the tree or the branch is nearby to you, simply they vanish in the nature. This method of covering invisible is the adaptation of the insect which resembles some special object to which an enemy is indifferent. These butterflies have various types of color and pattern which help them to appear as a dead leaf. When it is chased by a bird, it flies and perch on a branch or a trunk of tree. Then, it flaps its body, as if it is a dry leaf of the tree, which is moving because of the wind. It makes the bird confuse and puzzling, and the bird, flies away as it is difficult find the butterfly.

 During the dry season, the upper side is indigo-blue in color. Underside simulating a dry leaf, Antennae dark brown; head, thorax and abdomen very dark greenish brown; beneath, the palpi, thorax and abdomen ochraceous earthy brown.

 During the wet-season they have a uniform pale blue of a slightly lighter or darker shade, varying individually, but not turning to white towards the costal margin as in the dry-season specimens. Underside: ground-color on the whole darker than in the dry-season form, but with the same coloring.

 South Indian Blue Oakleaf (Kallima horsfieldi)