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Presentation of systematics Topic: Subclss pterygota Order orthoptera Order odonata Order phasmida

contents Class hexapoda Subclass pterygota Endopterygota Exopterygota Exopterygota orders Order Orthoptera Characters Examples Order odonata Charaters Examples Order phasmida Characters References

Class hexapoda: Hexa = six and poda = legs So it include insects having 3 pair of legs Two subclasses: Apterygota (primitive wingless insects) Pterygota (winged and secondarily wingless insects)

Subclass Pterygota: Pterygota means “wings,” Describes insects having wings, or once had wings in their evolutionary history Includes most of the world’s insect species The winged insects (Pterygota) distinct stages of development before they become adult. Incomplete metamorphosis (Egg > nymph > adult) Complete metamorphosis (Egg > Larva (more precisely: larval instars) > pupa > adult)

s Complete metamorphosis Incomplete metamorphosiss

Classification of pterygota The details of the process of metamorphosis allows the winged insects to be classified into two main groups: Exopterygota (insects with incomplete metamorphosis, without pupal stage) Endopterygota (insects with complete metamorphosis, including a pupal stage)[2]

Endopterygota: Refers to the development of the wings inside the body. Complete metamorphosis. External changes are greatest. The eggs hatch into larvae . Larvae may or my not have legs. Development of wing s is not visible in larvae.

After several molts pupa is formed. Pupa is inactive stage. Sometime pupa is protected by cocoon silk or found in earthen cell in soil. Big changes internally take place during pupal stage. After pupal stage highly active winged adult appears.

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Exopterygota: Exopterygota ("external winged forms") develop wings on the outside of their bodies without going through a true pupal stage, though a few have something resembling a pupa. The young resemble adults but have externally-developing wings. They undergo a modest change between immature and adult nymphs develop gradually into adults through a process of moulting.

Highly diverse insect super order, with at least 130,000 living species divided between 15 orders. include termites, locusts, thrips, lice and stick insects, among many other types of insects. Encompassing plant feeders, predators, and animal parasites, and living in nearly all habitats and areas where insects are found.[3]

Characteristics of Exopterygota: Simple or incomplete metamorphosis. The life cycle includes just three stages – egg, nymph, and adult There is gradual exchange in external appearance. Late nymph shows the development of the wing pads. But only in last molt functional wings are developed. The nymph usually have the same feeding habitat and resemblance with adults.

Exopterygota orders: Notoptera(ice-crawlers & gladiators) Plecoptera(stoneflies) Embioptera(webspinners Zoraptera(angel insects) Dermaptera (earwigs) Orthoptera (grasshoppers, etc) Phasmatodea(stick insects) Blattaria(cockroaches) Isoptera(termites) Mantodea (mantids) Psocoptera (booklice, barklice) Thysanoptera (thrips) Phthiraptera(lice) Hemiptera (true bugs) Odonata (dragonflies)

Order Orthoptera: Ortho = straight, ptera = wings. Hence these are insects with straight wings. Include (grasshoppers, crickets & katydids). Have incomplete metamorphosis. Nymphs look similar to mature adults, but lack fully-developed wings.

Characteristics Mandibulate , chewing mouthparts. Antennae have multiple joints, and are of variable length. Compound eyes. The first and third segments of the thorax are enlarged, while the second segment is much shorter. The final two to three segments of the abdomen are reduced, and have single-segmented cerci. Have a generally cylindrical body.

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They have two pairs of wings, which are held overlapping the abdomen at rest. The forewings, or tegmina, are narrower than the hind wings and hardened at the base, While the hind wing is membranous, with straight veins and numerous cross-veins. At rest, the hind wings are held folded fan-like under the forewings.

Usually enlarged hind femora/hind legs for jumping. Most are medium to large. This form of sound production is called stridulation, and involves rubbing the upper and lower wings or the hind leg and wing together to create a vibration.

Distinctive feature: Hind legs adapted for jumping. Tympanum (sound markers present). Have long ovipositor and long pronotum. Exist in terrestrial habitats. Very destructive to crops

Examples Grasshoppers

Crickets

Katydids

Order Odonata: Odonto’ refers to strong teeth on mandibles of adults. Includes dragonflies and damselflies. Incomplete. Nymphs and adults different in appearance. nymphs with gills called naiad. Indicate good water quality. Adults nearly water or terrestrial. Adults are moderate to large predaceous insects. Hemimetabolous: egg -> nymph (naiad) -> adult

The mouthparts underside of head and simple chewing mandibles. Have two ocelli and short antennae. Two pairs of long, transparent wings that move independently. Abundantly veined. Elongated abdomens. Big compound eyes. Excellent vision; can rotate head almost 360 to capture the pray. Long slender bodies. Have large rounded heads

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Distinctive features: Long needle like abdomen, prominent eyes, antennae short and setaceous Habitat almost all in lentic waters. Beneficial (predaceous on mosquitoes and other insects).

Examples Dragonflies

Damselflies

Order phasmida: The order name comes from the Greek word phasma, meaning apparition. Some entomologists call this order Phasmatodea. The order Phasmida includes some of the best camouflage artists in the insect world - the stick and leaf insects.

Nymphs and adults similar in appearance. simple metamorphosis. Eggs are laid, often dropping to the ground, as copulation takes place. In some species, females can produce offspring without fertilization by a male. These offspring are nearly always female, and males of those species are rare or non-existent.

Chewing mouthparts designed for breaking down plant material. Antennae are long and slender. Prothorax is short. Mesothorax & Mesothorax are very elongated. Leathery, elongate bodies and long thin, slender legs designed for walking slowly. None. Rarely 2 pair leaf like. Forewing very narrow and tough (=tegmina); hindwing membrane-like & folded; N. American species lack wings. Large 12-178mm.

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Distinctive features Elongated, cylindrical bodies, pencil like or stick like, slow moving. Foliage feeders on trees and shrubs.

Examples Stick insects:

Leaf insects:

References: http://insects.about.com/od/flyinginsects/p/char_pterygota.htm http://www.amentsoc.org/insects/fact-files/orders/pterygota.html http://www.answers.com/topic/exopterygota-