Introduction || Brief Notes on Insect Taxonomy

Brief Notes on Insect Taxonomy

The number of known insect species approaches to one million. Scientists suppose that about 1.5 – 10 million species of insects may live on the Earth. Author of this note described 18 new species of wasp-parasitoids during only one year in the Central Asia. How many species are waiting for their discoverers!

Taxonomy is a scientific means for classification and identification of living objects. To use those objects, you need clearly to distinguish them from others which frequently have small differences. Therefore, the taxonomy is not a calculation of wing number or leg number, as external observer could seem, but it is a kit of tools for identification of species, which have frequently enormous economical importance (direct or indirect). Taxonomists investigate both morphology and physiology, ecology, and other sides of living organism. It is not needed to tell about benefits and damages of insects. Bees – honey, wax, and pollination. Silkworm – silk. Locust – perished harvest. Colorado beetle – perished potato harvest. Malaria mosquitoes, Flies, Fleas, etc.

Insects were separated to the Class Insecta in the Phylum Arthropoda. The nearest relations of insects are myriapods (Myriapoda). However, remember that adult insects (imago) have only three pair legs in contrast to other arthropoda (e.g., spiders have four pair legs, myriapods have many).

Below, not all orders of insects are presented, since many insects are difficultly shot in natural habitats, or some species are obtained as not photogenic ones.

Class Insecta

Subclass Apterygota

Apterigota is the lowest representatives of the insect class, because they and their progenitors have never wings. They are secretly living. Specimens presented here were shot on the underside of toadstool developed on decayed tree. The insect size can be compared with a tubule diameter of the fungus.

Subclass Pterygota

These insects have wings, or if there are not, their progenitors had (Examples are: lice (Anoplura), mallophagans (Mallophaga), fleas (Aphaniptera)).

Winged insects are divided into two divisions: with semicomplete metamorphosis - Hemimetabola; and with complete metamorphosis – Holometabola.

Briefly, the insects have the complete metamorphosis when larva burst out of ovum is not similar to adult insect (imago), and after development, larva pupates. The pupa is relatively motionless phase, when the internal reorganization is taking place, i.e., a full transformation. From pupa, the winged insect appears. The example of the complete metamorphosis can be seen for butterflies on the page "How to Raise Butterfly".

As to semicomplete metamorphosis, the larva burst out of ovum is very similar to imago, but without wings or with rudimentary wings. The larva is molting and growing. After last molt, the larva develops wings and becomes the imago. The examples of semicomplete metamorphosis are presented below: Orders Orthoptera, Hemiptera, etc.

Division Hemimetabola

Order Odonatoptera

Who does not know dragonflies? These are large predatory-insects catching mosquitoes, flies, wasps, bees, etc. in the air. Their head has big eyes and strong mandibles. They have two pair of wings that are almost similar form with rich nervuration. Both imago and larva are predatory. Scientists, who found fossil dragonflies, indicated that appearance of fossil and modern forms is very similar. Continuation...

	Order Orthoptera Suborder Dolichocera Family Tettigosiidae Grasshoppers are confused with locusts. Unlike locusts, the grasshoppers have antenna length that is longer than length of all the body. Abdomen of grasshopper female has long ovipositor similar to a sword. Male of grasshopper chirms with special organ on the base of sheaths, therefore "music" of the grasshoppers sounds louder and more pleasant than one of locusts. Continuation...
	Suborder Brachycera Family Acrididae Antennae of locusts (unlike grasshoppers) are shorter than length of all the body. A male chirms by a friction of inner side of hideleg on protruded veins of sheath. Continuation...
	Order Homoptera Most famous representatives are aphids sucking sap of all the garden and forest plants. Unfortunately, at the South Urals there are no "singing" cicadas (the biggest specimens for the Order) which are common for South regions of Russia. Continuation...
	Order Hemiptera Do you remember smell of bug when you touch it during collecting raspberry? This is its protection, because the bug is afraid that you would eat it, but after such the smell…! The representatives of the Order Hemiptera have the first pair of wings becoming the sheaths which are not fully hardened. See photos...

Division Holometabola

	Order Coleoptera Beetles – coleopterous insects. The first pair of wings became stiff for protecting the second pair of wings for flying. This group has the most number of insect species. Continuation...
	Order Neuroptera Lacewing is the most famous representative in our region. Continuation...
	Order Mecoptera This order has a small number of insect species. The basic features are elongated form of mouthparts and declinate end of abdomen as the scorpion one.
	Order Lepidoptera Butterflies - scale-winged or lepidopterous insects. The wings are covered with small scales which are masking a wing nervation. During flying, the anterior and rear wings are coupled together and operate as a single whole. Continuation...
	Order Hymenoptera This is one of the biggest insect groups. Both, anterior and rear, wings are transparent and membranous. The anterior and rear wings are coupled together and operate as a single whole. Most famous representatives are: bees, wasps, bumblebees, ants, etc. Continuation...
	Order Diptera Dipterans - two-winged flies. Taxonomists believe that this group is the most developed. These insects have one pair wings. The second pair was reduced. The dipterans are various flies, mosquitoes, etc. Continuation...