However, some other arthropod classes like Diplopoda millipedes and Chilopoda centipedes are often considered by entomologists. Even a few non-arthropod groups like snails and slugs Phylum — Mollusca are sometimes referred to entomologists.
The Class Hexapoda is generally studied under a classification system with approximately 30 orders. Many of these are of minor importance and are studied only from the standpoint of scientific interest. Considered here are some of the more important orders which are likely to be encountered.
Many taxonomists disagree on the number of orders and their names. Thus, this scheme will often vary with different authors. Menu Home Insect Orders Search this website. Overview of Insect Orders Classification Animals are classified into the animal kingdom. The standard groups in a typical complete classification of species are the example is for a honey bee, Apis mellifera Linnaeus There are often additional groups used that are intermediate to the groups listed.
Terminology, Classification and Use of Scientific Names No capital letters are used in common names unless they contain a proper noun. The web spinners have silk glands in their front legs and weave nests under leaf litter and in tunnels where they live. Webspinners live in tropical or subtropical climates. The order Dictyoptera includes roaches and mantids.
Both groups have long, segmented antennae and leathery forewings held tightly against their backs. They undergo incomplete metamorphosis. Worldwide, there approximately 6, species in this order, most living in tropical regions. Termites feed on wood and are important decomposers in forest ecosystems. They also feed on wood products and are thought of as pests for the destruction they cause to man-made structures. There are between 2, and 3, species in this order. Little is know about the angel insects, which belong to the order Zoraptera.
Though they are grouped with winged insects , many are actually wingless. Members of this group are blind, small, and often found in decaying wood. There are only about 30 described species worldwide. Bark lice forage on algae, lichen, and fungus in moist, dark places. Booklice frequent human dwellings, where they feed on book paste and grains.
Entomologists have named about 3, species in the order Psocoptera. Biting lice are ectoparasites that feed on birds and some mammals. There are an estimated 3, species in the order Mallophaga, all of which undergo incomplete metamorphosis. The order Siphunculata are the sucking lice, which feed on the fresh blood of mammals. Their mouthparts are adapted for sucking or siphoning blood. There are only about species of sucking lice. Most people use the term "bugs" to mean insects; an entomologist uses the term to refer to the order Hemiptera.
The Hemiptera are the true bugs, and include cicadas, aphids , and spittlebugs, and others. This is a large group of over 70, species worldwide. The thrips of order Thysanoptera are small insects that feed on plant tissue. Many are considered agricultural pests for this reason. Some thrips prey on other small insects as well.
This order contains about 5, species. Commonly called the order of lacewings , this group actually includes a variety of other insects, too: dobsonflies, owlflies, mantidflies, antlions, snakeflies, and alderflies.
Insects in the order Neuroptera undergo complete metamorphosis. Worldwide, there are over 5, species in this group. This order includes the scorpionflies, which live in moist, wooded habitats.
Scorpionflies are omnivorous in both their larval and adult forms. The larva are caterpillar-like. There are less than described species in the order Mecoptera.
Pet lovers fear insects in the order Siphonaptera - the fleas. Fleas are blood-sucking ectoparasites that feed on mammals, and rarely, birds. There are well over 2, species of fleas in the world. This group, the beetles and weevils, is the largest order in the insect world, with over , distinct species known. The order Coleoptera includes well-known families: june beetles, lady beetles, click beetles , and fireflies. All have hardened forewings that fold over the abdomen to protect the delicate hindwings used for flight.
Insects in this group are parasites of other insects, particularly bees, grasshoppers, and the true bugs. Although they are very common, few people study the group and many people never see them at all unless they study the bird or mammal hosts. The Pscocoptera have long been regarded as phylogenetically close to the Phthiraptera, but recent research has suggested that the Phthiraptera may even be a subgroup of the Psocoptera, within the wider group of Psocodea.
Not surprisingly there is some reluctance to accept this view fully, because it would have implications for the integrity of the Psocoptera. The thrips are probably most closely related to the Hemiptera, based on certain mouthpart structures and other characters. Their minute size means that they are a little known group, and many people are surprised to learn how many species there are. Some feed on fungi, others on higher plants, and a small number of these can be agricultural or horticultural pests.
The larvae look very different to the adults, and undergo metamorphosis in a pupa where the wings develop internally. Adult beetles have a distinctive appearance, with the hard elytra covering most of the body and meeting down the mid-line, which makes them easy to recognise but this apparent uniformity hides an enormous variety of life histories.
There are numerous variations in larval forms and feeding habits, and beetles can be found in a wide range of habitats. In turn this makes them important in ecological research and environmental surveys. The exact relationships of the Diptera with other insect orders are still open to question; undoubtedly they belong in the loosely defined group of Panorpoids, which includes the Lepidoptera, Mecoptera, Siphonaptera and Trichoptera.
This group is arguably the largest and most complex of all the orders of insects and they seem to be only distantly related to the other endopterygotes.
There is evidence that they are closer to the Panorpid groups rather than the Coleoptera but the picture is far from clear. Although their monophyly is not in doubt, it is hard to give defining characters for the whole group that are not plesiomorphic. The close relationship between the Lepidoptera and Trichoptera is often cited as one of the classic sister-group relationships at ordinal level in all the insects.
The flattened scales on the wings of butterflies and moths are clearly derived from the normal hairs found on caddisfly and many other wings; indeed such scales occur sporadically in several other insect groups, even in the Archaeognatha, for example.
Traditionally the Mecoptera have been regarded as closely related to the Diptera and, although this is still accepted, there is increasing evidence that at least one family, the Boreidae, has a closer relationship with the Siphonaptera. If this is true, then it might have implications for the monophyly of the Mecoptera, or else it might mean that the Siphonaptera would be reduced to a subgroup. In early texts the Megaloptera were included within the Neuroptera, together with the Raphidioptera, but they have long been recognised as a distinct order.
The monophyly of this group of three orders, sometimes termed the Neuropterida, is not in question, but the exact relationships between them are yet to be fully resolved. Adult Megaloptera have broad flattened heads with biting mouthparts, and two pairs of very similar wings; all the larvae are freshwater predators. Since the time of Linnaeus the Neuroptera were often treated as a convenient receptacle for the diverse groups of endopterygote insects that did not fit anywhere else; the modern view is that the group is closely related to the Megaloptera and Raphidioptera.
To avoid confusion with the name Neuroptera in its older broad sense, some authors employ the name Planipennia for the modern restricted usage. Of the three orders in the Neuropterida, the Raphidioptera may be the most basal, leaving the Neuroptera and Megaloptera as sister-groups. They get the common name of snakeflies from their elongate pronotum which is mobile and can be elevated such that the insect resembles a snake about to strike at its prey; the German name of Kamelhalsfliegen, or camel-neck flies, is equally appropriate.
Both the adults and larvae are predatory, though adults are also reported as feeding on pollen. Being obligate ectoparasites on mammals and birds, adult fleas have become highly specialised in their morphology and life histories; as a consequence their affinities with other insect groups have long been debated.
Traditionally they have been linked with the Diptera or Mecoptera; recent morphological and molecular studies have suggested a close relationship with the family Boreidae within the Mecoptera. The Strepsiptera are one of the strangest insect groups, little known to most people, and hardly seen even by entomologists unless they make a special effort to study them.
All are obligate endoparasites in other insects and, as so often in parasitic groups, there are many unique morphological and biological adaptations. Trichoptera are closely related to the Lepidoptera, forming the group Amphiesmenoptera, and the two orders are often cited as being one of the best examples of a sister-group pair at the ordinal level.
Shopping cart Your shopping cart is empty. Create new account Forgotten password. This question is for testing whether or not you are a human visitor and to prevent automated spam submissions.
Covid Updates You can read our Covid updates on the dedicated page. Here is an example using the marmalade hoverfly, Episyrphus balteatus:
0コメント