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Insect Taxonomy
Diversity
By: Patricia Brown
Insect Orders
1)Ephemeroptera
6)Orthoptera
11)Diptera
2)Odonata
7)Phasmida
12)Siphonaptera
3)Blattaria
8)Hemiptera
13)Hymenoptera
4)Isoptera
9)Coleoptera
14)Mantodea
5)Dermatptera
10)Lepidoptera
15)Plecoptera
Ephemeroptera
Includes mayflies
Mayflies are small to medium sized insects with an average wingspan up to 15 millimetres.
As their name suggests, mayflies have only a short adult life ranging from a few hours up to
a day or two depending on the species. Mayflies can be recognised by the following
characteristics: 2 pair of membranous wings, hind wings much smaller than the forewings,
short, fine antennae, mandibulate mouthparts, etc.
Odonata
Includes Dragonflies and
Damselflies
Many characteristics distinguish Odonata from other groups of insects -- minute antennae,
extremely large eyes (filling most of the head), two pairs of transparent membranous
wings with many small veins, a long slender abdomen, an aquatic larval stage (nymph)
with posterior tracheal gills, and a prehensile labium (extendible jaws underneath the
head).
Blattaria
Includes Cockroaches
They are……
• quick moving, dorsoventrally flattened body
• large shield-like pronotum that extends forward to at least partially cover the head
• two pairs of wings (in some species, the wings are small)
• leathery, membranous wings
• chewing mouthparts
• two cerci
• hemimetabolous metamorphosis (egg — nymph — adult)
Isoptera
Includes Termites
Termites are usually small or medium sized, whitish or colourless insects, with short
antennae. They have strong biting mouthparts with which to chew seeds, wood or leaves.
Apart from the Hymenoptera (bees, ants and wasps), termites are the only insects that live in
social groups. In fact, unlike the Hymenoptera, even the young termite nymphs are active in
running the termite community.
Living in a society means having a division of labour. In other words, groups of individuals
have particular roles and these groups are known as castes. These are:
• Kings and queens
• Workers
• Soldiers
Dermatpera
Includes Earwigs
Earwigs are a distinctive group of insects of small to medium size, ranging from 5 to 50 millimetres in length.
Earwigs are sometimes confused with Staphylinid beetles, but can be distinguished from the latter by the presence of
pincer-like cerci, which Staphylinid beetles lack. Earwigs are mostly dark coloured (brown to black) and can be
recognised by the following features:
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Flattened elongated body
Heavily sclerotised pincer-like cerci. Females have straight cerci with a inward pointing tip and males have curved
cerci
2 pairs of wings. The forewings are short and protectively hardened. The hind wings are membranous and folded
in a fan-like way underneath the forewings when not in use. Some species are also wingless
Chewing (mandibulate) mouthparts
Moderately long antennae
Orthoptera
Includes Grasshoppers
Grasshoppers, crickets, katydids and locusts all belong to the order Orthoptera which means 'straight wings'. Most are
easily recognisable by their hind legs, which are usually enlarged for jumping. They are often easily seen jumping away
when disturbed or heard 'singing' at night. They are mainly medium to large insects with some species in Australia growing
to a length of 10 centimetres. There are about 3000 species in Australia and all can be distinguished from other insects by
the following features:
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2 pairs of wings. The forewings are narrower than the hind wings and hardened or leathery at the base. They are held
roof-like overlapping the abdomen at rest. The hind wing is membranous and held folded fan-like under the forewings
when at rest
Mandibulate mouthparts
Large compound eyes
Antennae may be short to very long depending on the species. Grasshoppers have relatively short antennae while
crickets and katydids generally have long antennae
Hind legs are enlarged and modified for jumping
Phasmida
Includes Stick and Leaf Insects
Phasmida are variable in appearance, ranging from relatively generalized forms, to some that are wonderful mimics of sticks
and/or leaves. They display varying degrees of brachyptery, and can be winged or wingless. The tarsi have three articles in
Timema Scudder and five in other Phasmida. Cerci are composed of one article, except for adult males of Timema which have a
lobe on the right cercus.
Sexual dimorphism is usually extreme: the males are smaller and more gracile than the females. Reproduction is typically
sexual, but parthenogenesis occurs frequently. The egg capsule is distinctively shaped, possessing a lid called the operculum
and a micropylar plate (Sellick, 1997). Eggs are large and oftentimes highly sculptured resembling plant seeds. They are laid
singly, and are dropped, flicked, buried, glued to a surface, or riveted to a leaf. Some species that drop the eggs rely on ants to
disperse them in a process analogous to myrmecochory (Windsor et al., 1996). The entire life cycle from egg to adult can take
from several months to several years depending on the species.
Hemiptera
Includes Bugs, Aphids, & Cicadas
The insects in this order are extremely diverse in their size, shape and colour. There are about 6000 described species in Australia,
ranging in size from 1 to 110 millimetres in length. The name Hemiptera means 'half wing' and all hemipterans share the following
features:
• 2 pairs of wings, although some species may be wingless and others have only forewings. Wings are generally membranous but in
some species the forewings may be hardened at the base
• Piercing or sucking mouthparts appearing as a sharply pointed tube known as a proboscis or rostrum, which extends from the
underside of the head
•Compound eyes of various forms
• Up to 3 ocelli present
• Antennae vary and may be either short, or long and conspicuous
Coleoptera
Includes Beetles
Beetles constitute the largest and most diverse order of insects on earth, making up about 30% of all animals.
There are over 300 000 species of beetles worldwide and over 28 000 species spread across 117 families in
Australia. Beetles come in a variety of shapes and colours and can range from 0.4 to about 80 millimetres in
length. Due to the variation within the order it is difficult to give a general description however all beetles
characteristically have the following features:
•2 pairs of wings. Forewings hardened, hind wings membranous
•Mandibulate mouthparts which are designed for biting and chewing
•Antennae present in a variety of forms
•Compound eyes in a variety of sizes and shape
Lepidoptera
Includes Moths and Butterflies
•2 pairs of membranous wings that are covered in tiny scales which overlap like shingles on a roof. A few moths are
wingless
• Large compound eyes
• One ocelli present above each eye
• Antennae present. Antennae are long and slender in female moths and generally feathery in male moths. Butterflies have
clubbed antennae
• Mouthparts are formed into a sucking tube known as a haustellum
The larvae are typically known as caterpillars and have a sclerotised head with chewing (mandibulate) mouthparts, 3 pairs
of thoracic legs and often short, unsegmented prolegs on the abdomen
Diptera
Includes Flies and Mosquitoes
One pair of membranous wings
•Hind wings are reduced to small club like structures called halteres. The halteres are used
as stabilisers during flight
• Sucking mouthparts, sometimes adapted for piercing e.g. mosquitoes
•large compound eyes
•short simple antennae, frilled or bushy in mosquitoes and crane flies
Siphonaptera
Includes Fleas
•Laterally compressed bodies
•Piercing-sucking mouthparts
•Enlarged hind legs adapted for jumping
•Strong tarsal claws adapted for holding onto their hosts
•Backward pointing hairs and bristles for ease of movement through the hair of a host
•Small antennae which tuck away into special groves in the head
The species Ctenocephalides felis (above) is the introduced cat flea but can survive on a wide range of host
species. The larvae of all fleas appear grub-like and are usually found in the nests of their host or other areas
where they commonly rest.
Hymenoptera
Includes Ants, Bees, & Wasps
•Two pairs of membranous wings, although some may be wingless such as some species of female wasps and the worker caste of
ants
• The forewings are larger than the hind wings and are held together by small hooks (see below)
• Females usually have a hardened ovipositor, which may be modified for sawing, piercing or stinging
• Most hymenopterans have a constriction between the first 2 segments of the abdomen, which is known as a 'wasp waist'
• Chewing (mandibulate) mouthparts, although in some species such as bees the lower lip is modified to form a tongue
•Compound eyes, usually large
The larvae of hymenopterans lack many of the above external features. They vary in body shape and size depending on the species.
Some display a distinct head,a thorax with 3 pairs of legs and an abdomen, although most are grub-like with no legs.
Mantodea
Includes Praying Mantids
•Elongated body
•Raptorial front legs with one or two rows of spines
•2 pairs of wings, both of which are used in flight. Although some species have reduced wings and others are wingless
• Forewings protectively hardened to cover the membranous hind wings when at rest
•Very mobile triangular shaped head with distinctive ocelli
•Large compound eyes
•Short to medium sized filiform antennae
The males of most species are fully winged while many females have either reduced wings or no wings at all. The nymphs of praying
mantids look like small adults but lack wings or have developing wing buds.
Some species of Neuroptera in the family Mantispidae, like the one pictured below can be mistaken for praying mantids as they also
have raptorial front legs, however further examination reveals they do not have the hardened forewings present in Mantodea.
Plecoptera
Includes Stoneflies
•Elongated, flattened, soft body
•2 pairs of membranous wings that are held curved around the body at rest. Some species are
wingless while others have reduced wings
• Hind wings slightly wider than forewings
•Long legs
•Mandibulate mouthparts
•2 cerci at tip of abdomen
The larvae of stoneflies are aquatic and appear similar to the adults but lack wings. Larvae also
possess external gills along the edge of their abdomens and at the tip.
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END!!!