A dragonfly has lived a whole life before it is a dragonfly. From egg to pro-larva to larva and then after years first an image and then a dragonfly. The larva, which hatches, does not look like a dragonfly at all. After many molts, the larva very slowly becomes an image (a dragonfly). The image creeps out of the larva’s back very slowly and must first heat up and color before it can fly away. Subsequently, such a beautiful dragonfly lives on average only six to eight weeks.
- Order of the dragonflies
- Difference damsels and dragonflies
- Dragonflies and their families
- Characteristics of the dragonfly
- Large facet eyes
- Spiky legs
- Mustache or drooping mustache at the darter
- Dragonfly mating
- From egg, pro-larva, larva to dragonfly
- Lay eggs
- Sexually mature
Order of the dragonflies
Dragonflies (Odonata) are an order of insects (Pterygota) with the main order the Exopterygota of which the dragonflies (Odonata) are one of the nineteen orders. The order of the dragonflies consists of two sub-orders namely:
- damselflies or equals (Zygoptera);
- true dragonflies (Anisoptera) or unequal wings. With the real dragonflies the same is meant as with dragonflies.
Difference damsels and dragonflies
A big and visible difference between the damselflies and the dragonflies are the wings. The damselfly is an equal-winged insect and the dragonfly is a dissimilar insect. Both species have two hind wings and two forewings. Transparent wings with a network of veins and a colored spot on the leading edge, the pterostigma or the wing spot. With dragonflies, the front and rear wings are not equal to each other and are not connected to each other so that they can be used separately. In addition, the rear wings are wider than the forewings and the wings at rest are spread out to their full width. In damselflies the fore and hind wings have the same shape and function and are folded together on the back when at rest. It therefore seems as if there is only one pair of wings instead of two pairs. Another difference is that dragonflies are on average 3 to 8.5 centimeters in size and the damselfly is 2.5 to 5 centimeters in size. Where the abdomen of the damsel is long, round and slender, the dragonfly has a thick and flattened abdomen.
Dragonflies and their families
Many types of dragonflies occur worldwide. Dragonflies with the most beautiful colors and strangest shapes. They are enthusiasts for the warmer areas. About 150 dragonfly species occur in Europe. About 75 species live in the Netherlands and Belgium. The families in both countries are:
- Glaziers (Aeshnidae);
- Rhombs (Gomphus);
- Spring dragonflies (Cordulegastridae);
- Glossy dragonflies (Corduliidae);
- Corn bolts (Libellulidae).
The dragonfly can be spotted near stagnant fresh water. Water where the larvae live and eventually become a dragonfly. Dragonflies prefer clean water and no dragonflies can be seen in polluted water or in salt water. Some species like to live with running water such as:
- source sludge bubbles.
Characteristics of the dragonfly
The characteristics of a dragonfly include:
- large facet eyes like two hemispheres;
- large wings with a wing spot (Pterostigma);
- an elongated abdomen;
- spiky legs.
Large facet eyes
The most striking feature of the head are the large, multi-faceted eyes. Facet eyes or compound eyes of the dragonfly consist of 50 thousand facets (omnatidium) and each facet (light detector) has its own lens. Where humans have one lens, the dragonfly has tens of thousands. The top part sees sharp and the bottom part of the big eye sees everything up close. With dragonflies the two eyes touch each other on top of the head, while this is not the case with damselflies. Under the convex eyes the dragonfly has two small blades or antennae, which are barely visible. The antennae have specific receptors that allow the dragonfly to smell. A dragonfly can also measure speed with the antennas.
The dragonfly is a dissimilar insect and has two pairs of wings, two front wings and two hind wings. Uneven-winged means that the rear wings, which are implanted behind the front wings, can be controlled separately. The four wings appear mesh-like, thin and transparent through a network of veins. Because the two pairs of wings work separately from each other, the dragonfly is an artist in flight, such as:
- standing still in the air (like a helicopter);
- fly backwards;
- take off vertically.
The wings consist of a network of veins. In the leading peripheral veins of all four wings, dragonflies (just like damsels) have a colored wing spot (pterostigma). The pterostigma fills one cell of the veins with a characteristic color. Filling one cell in the wing adds weight to the wing and slightly increases the dragonfly’s hover speed. The color of the pterostigma makes a lot of difference for the identification of the dragonfly. For example, the brown-red darter has a red pterostigma, the flat belly a dark blue pterostigma and the wandering darter has a yellow pterostigma.
The coloring abdomen of the dragonfly consists of ten segments and is very flexible, which is important for mating. The abdomen also has a strengthening function for steering in flight. The colors of the segments help you find a suitable partner. The colors are also decisive in determining, but there is a catch. A number of species are very difficult to identify, because the color:
- of the older females becomes the same as that of the young males;
- can be adjusted to body temperature and thus can change;
- fades when the dragonfly gets older;
- in older males it may change due to a powdery white substance on the abdomen (frosting).
The legs of the dragonfly have a kind of spines (thorns). The spines ensure that captured prey cannot escape. In some species the legs also have an extra colored stripe over the spiky legs. It takes identification a lot further.
Mustache or drooping mustache at the darter
What the correct identification of the brown-red darter, blood-red darter and brick-red darter (dragonflies from the family of the cornbolts (Libelludae) also brings further is to see if the mustache is present at the dragonfly. (mustache) Only with the brick-red darter does the black mustache run down like a drooping mustache, another step closer to determining which darter has been seen or photographed.
Prior to mating, the male transfers sperm to a secondary sex organ on the abdomen. He then grabs a female, near water, by grasping her with his abdomen appendage behind the head and then the female brings her abdomen to the secondary sex organ on the male’s thorax, the famous heart-shaped tandem position or mating wheel. Together they fly on and the duration of mating can last from a few seconds to several hours.
From egg, pro-larva, larva to dragonfly
Dragonflies are a primitive type of insect. The larva of a dragonfly does not resemble an adult dragonfly and undergoes an incomplete transformation. By molting many times as a larva, it only becomes clear at the last molt that it will become a dragonfly. From larva to dragonfly is done as follows:
- Lay eggs;
After mating, the female will lay the eggs in the water. Like a dancer, she flies over the surface of the water with her abdomen dipping and lays the eggs in the water. Dragonflies can lay up to 200 to 1000 small eggs. The eggs hatch within a few weeks, depending on the temperature. In the northern species, such as the northern banded ground dragonfly or northern white-beaked dragonfly, the eggs laid in the fall can remain in egg shape all winter before the next stage arrives.
The next stage is that after the egg hatches, the prolarve appears. A small and worm-like animal that moves around in a flounder because a prolarve has no legs. Once a suitable spot has been reached, the prolarve will molt and the young larva will appear.
The larvae of a dragonfly are also called nymphs. The nymphs have 3 pairs of legs, large eyes and large jaws and are not afraid to catch prey that is the same size as themselves. These larvae molt nine to sixteen times and the wings become more visible after each molt. The larvae grow to about 5 centimeters long, with a wide abdomen and folded under the head a retractable grab that catches the prey. The larval stage can last one or more years.
After each molt of a larva that lives in the water, it starts to resemble a dragonfly more and more. The permanent change from larva to dragonfly preferably takes place early in the morning (because the chance to serve as prey is then the smallest) on the waterfront, in the reeds or another crop and takes a few hours. After the larva has found a spot on the bank, the skin at the thorax bursts and the image emerges. The thorax is located between the head and the abdomen of the larva. Very slowly, the fledgling, delicate and light-colored dragonfly (the image) becomes more and more visible. The image grabs onto a plant stem and pulls out of the larva, pumping up through body fluids, and after the wings have dried and hardened by the sun, the image flies away. For several days, the fresh images can be recognized by their shiny wings before it is a dragonfly.
After hatching and the fly away of the newly born dragonfly (image) it is not immediately sexually mature. The period in which an image becomes a dragonfly (the maturation phase) lasts on average one to two weeks. Only then will the dragonfly have enough energy to think about reproduction.
Do you know
People who study dragonflies are called odonatologists.