An Assignment for

Partial Fulfilment

Of

ENT-504

(CLASSIFICATION OF INSECTS)

On

NEUROPTERA

Prepared by:

Mayank V. Patel(2ndsem.)

Reg. No. 04-1904-2012

Submitted to:

Dr. D. M. KoratAssistant Director of Research

AAU, ANAND

Neuroptera

The name Neuroptera is derived from the Greek word"neuron" meaning sinew and "ptera" meaning wings. The modern English translation "nerve-wings" is appropriate because it alludes to the extensive branching found in the wing veins of most Neuroptera.

Scientific classification :-

Kingdom Animalia

Phylum Arthropoda

Class Insecta

Subclass Pterygota

Infraclass Neoptera

Superorder Endopterygota

Order Neuroptera

Suborder Planipennia, Megaloptera

Example Lacewing, Dobsonfly,

Ant lion

Classification

• Holometabola

– complete development (egg, larva, pupa, adult)

• Neuroptera is divided into two suborders:

– Planipennia (antlions, lacewings and their relatives)

– Megaloptera (alderflies and dobsonflies)Raphidiodea (snakeflies)

• In adults, the suborders are distinguished by the shape of the wings and the length of the prothorax. 

• In larvae, the suborders are separated by habitat and characteristics of the mouthparts.

Morphological characteristics

Four membranous wings with many cross veins and extra branches of the longitudinal veins.

Fore and hind wings similar in shape and venation. Held roof-like over the body at rest.

Soft-bodied

Mouthparts mandibulate

Antennae long and many segmented

Biological summary for the order

Life history

• Eggs -

– Sialidae - laid in even rows of 300-900 in compact masses on substrates overhanging aquatic habitat.

– Rhaphidiidae - eggs laid under bark and hidden areas.

– Sisyridae - masses of 2-5 oval whitish to yellow eggs are covered with a web of white silk.

– Laid singly or in clusters at the end of silken threads in many families.

• Larvae -

– Megaloptera

• Aquatic

• Many instars with 1-5 years to develop. Late stage larvae abundant in late winter or early spring.

– Raphidiodea

> Live under bark of trees and in soil. > Semi voltine with 10-11 instars. > Overwintering occurs in larval stage and

occasionally in pupal stage.

– Planipennia

• Terrestrial

• Usually 3 larval instars

• Overwinter in all stages except eggs.

• Pupae

– Often form a silken cocoon to pupate or pupal cells in soil or organic material.

– Some pupae are able to move about prior to ecdysis.

Adult

– Antennae filiform, multisegmented

– Chewing mouthparts

– Fore and hind wing membranous, similar in size

– Extensive branching of venation in all wings; crossveins abundant especially along leading edge (costal margin)

Habitat

• Aquatic species live adjacent to water. Sialidae adults are found on shore plants beside slowly flowing water near their larval habitat.

• Terrestrial species variable living on plants and stalking prey or under bark.

Habits (mode of existence)

• Most are predaceous as adults and larvae in aquatic and terrestrial habitats.

• Some do not feed.

Economic Importance

• Larvae of Megaloptera are important predators in aquatic ecosystems.  They also serve as food for fish and other aquatic vertebrates. 

• Lacewing larvae are beneficial as predators of agricultural pests (aphids, whiteflies and scale insects).

• Some species are reared and sold commercially as biocontrol agents.

Important families with suborders

Planipennia :-

– Chrysopidae -- Green lacewings

– Hemerobiidae -- Brown lacewings

– Myrmeleontidae -- Ant lions

– Sisyridae -- Spongeflies

– Mantispidae – Mantidflies

– Ascalaphidae -- Owlflies

Megaloptera :-

– Corydalidae -- Dobsonflies

– Sialidae -- Alderflies

– Raphidiidae -- Snakeflies

Chrysopidae

• E.g. Green lacewing (Chrysoperla spp.)

• Most larvae are active predators and have modified jaws, which they use to catch small insects and suck out their insides. (Suctorial type mouth part)

Hemerobiidae

• These insects differ from the somewhat similar Chrysopidae(green lacewings) not only by the usual colouring but by the wing venation: hemerobiids having numerous long veins lacking in chrysopids.

• Some of the costal cross veins are forked, unlike in green lacewings. 

• Hemerobiid larvae are usually less hairy than chrysopid larvae

• Adults & Larvae both are predaceous

Green Lacewing larvae camouflaged against ants

Myrmeleontidae

• E.g. Ant lion (Distoleon tetragrammicus)

• Ant lions are weak fliers as adults.

• The pits are dug in loose sand and as there name suggests there main food items are often ants.

• The larvae will interfere with any ant that looks like it might be getting out of the pit by flicking grains of sand at it to make it loose its footing and thus fall into the waiting larvae's jaws.

• There are about 2,000 species of ant lions in the world.

Mantispidae

• E. g. Mantispa sp.

• Mantidflies often referred to as Mantispids possess raptorial forelegs much like those of the similarly named praying mantids which they use in the same way.

• The males use pheromones instead of sound to attract females. During courtship the male raises his forelegs in the air while raising and lowering his wings.

• The eggs like those of the Green Lacewings are laid at the end of a thin stalk. The eggs soon hatch and immediately enter a state of diapause.

Corydalidae

• E.g. Dobsonfly (Corydalus cornutus)

• Wingspans can be twice as long as their body length.

• Dobsonflies spend most of their life in the larval stage, during which they are called hellgrammites.

• Hellgrammites live under rocks at the bottoms of lakes, streams and rivers, and prey on other insect larvae with

the short sharp pincers on their heads, with which they can also inflict painful bites on humans. The larvae reach up to 2" to 3" in length, with gills all along the sides of their segmented bodies that allow them to breathe underwater.

• Their gills, primitive nervous systems, and hard, segmented bodies means hellgrammites can survive for long periods underwater.

Sialidae

• E.g. Alderfly (Sialis lutaria)

• They lack ocelli and their fourth tarsal segment is deeply bilobed.

• Dead alderfly larvae are used as bait in fishing.

Raphidiidae

• E.g. Snakeflies (Raphidia notata)

• Long-necked predators of small arthropods

• Adult snakeflies are characterized by having an elongate prothorax but no modification of the forelegs. They have strong and relatively unspecialised mouthparts, and large compound eyes.

• The females typically have a long ovipositor, which they use to deposit their eggs into crevices in bark or rotting wood. The wings are similar in size, with a primitive venation pattern, and a thickened costal margin.

• The larvae have large heads with projecting mandibles. The head and the first segment of the thorax are sclerotised, but the rest of the body is soft and fleshy.

• They have three pairs of true legs, but no prolegs.

• However, they do possess an adhesive organ on the abdomen, with which they can fasten themselves to vertical surfaces.

• The larvae can take up to two years to develop.

Difference between Brown Lacewing & Green Lacewing

Brown Lacewing Green Lacewing

E.g. Hemerobius stigma E.g. Chrysoperla carnea Stephens

Wings are brown in colour Wings are green in colour

Adults & Larvae both are predaceous Only Larval stage is predaceous

Presence of hook on backside of larvae Absence of hook