3. External Insect Anatomy

Name the three segments of an insect

Head

Thorax

Adbomen

What are the main parts of the head

Antennae

Compound Eyes

Simple Eyes

Mouth parts

What are antennae.

Why are they important for pest control

Sensory organs mainly used to detect

• chemicals/odours

• Pheromones

• Air vibrations

• Touch

• Sound (some insects)

They are also useful for identification

What are compound eyes

Compound eyes are eyes made up of many individual units called Ommatidia.

They detect:

• Movement

• Light

• Shape

• Colour (many insects)

What are the individual units that make up compound eyes

Ommatidia

What are ommatidia?

They are the individual visual units that make up the compound eyes

What are Ocelli

Simple eyes

Detects changes in light intensity

does not form detailed image

What are mouthparts?

What are the different types

Mouthparts are modified according to what and how the insect feeds

They can therefore be used to identify feeding behaviour and damage the pest can cause

Chewing

Piercing-sucking

Siphoning

Sponging

Rasping-sucking

Chewing-lapping

What Pests have chewing Mouth parts (8 orders and 13 types)

• Blattodea: cockroaches and termites

• Coleoptera: beetles and weevils

• Orthoptera: grasshoppers, crickets and locusts

• Zygentoma: silverfish

• Hymenoptera: ants

• Psocodea: booklice

• Lepidoptera larvae: caterpillars

• Hymenoptera larvae: bee and wasp larvae

Mandibles chew and grind solid food/material

What Pests have Sponging Mouth parts

• Houseflies

• Blowflies

• Flesh flies

• Other non-biting flies

They soften solid food with saliva and sponge up the liquid.

What Pests have piercing-sucking Mouth parts (name 4)

• Mosquitoes

• Bed bugs

• True bugs

• Fleas

• Lice

• Biting midges

They pierce skin or plant tissue and suck blood, sap or other fluids.

What Pests have Siphoning Mouth parts

• Adult butterflies

• Adult moths

They use a long, coiled proboscis to suck nectar and other liquids.

What Pests have Rasping sucking Mouth parts

• Thrips

They scrape or rasp plant tissue and suck up the fluids.

What Pests have chewing-lapping Mouth parts

• Bees

• Wasps

They use mandibles for chewing and a tongue-like structure for lapping liquids.

Reduced or variable mouthparts

• Non-biting midges

• Some gnats

• Adult male mosquitoes

Some do not feed as adults, while others feed on nectar or other liquids.

What is the thorax responsible for

What are the main parts of it

responsible for movement

Contains the major muscles

has three segments

• Prothorax - Bears the foreleg

• Mesothorax Bears middle leg and forewing

• Metathorax Bears hindleg and hindwings

Name the parts of the insect’s leg

Coxa

Trochanter

Femur

Tibia

Tarsus

Claws

What attached to the prothorax

Front leg

wat attached to the mesothorax

middle leg

Forewing

what attached to the metathorax

Hind leg

Hind Wing

What are the purpose of wings

Flight

Name the different type/modifications of wings

Membranous wings

Tegmina

Elytra

Halteres

Scaled wings

What are membranous wings

What insects have them

Thin flexible wings supported by veins and used for flight

Bee, wasps and flies

What are tegmina

Hardened forewings used to protect the insect’s hindwings

Found on Grasshoppers and cockroaches

What are elytra

Strong Hardened forewings used to protect the insects hind wings and abdomen

Found on beetles

What are Halteres

Modified hindwings in Diptera that are used for balance during flight

Found on Flies

What are scaled wings

Wings covered in scales

Mouth and butterflies

What is the role of the abdomen

Holds reproductive and digestive organs

Contains most of the spiracles

May have cerci and reproductive organs attached

What is the Cerci

Paired appendages attached at the posterior abdomen that can detect tough or air movement

Cockroaches have cerci which helps with their thigmotaxis

What is the Ovipositor

Female structure

• Used to lay eggs

• Modified into stings on Hymenoptera

What are the holes that are part of the respiratory system

Spiracles

What are spiracles

External openings along the thorax and abdomen that are the start of the insects tracheal breathing system

What is the integument

Entire body wall of insect

Three parts

Cuticle/exoskeleton - non living

-Epicuticle - Waxy layer that reduces water loss

- Pro cuticle

• Exocuticle - gets split open during moulting

• Endocuticle - gets absorbed during moulting

Epidermis -living cell layer that produces cuticle

Basement membrane - The supporting layer beneath epidermis

What is the role of the exoskeleton

Protect the internal organs

Provide support for the insect

Stop water loss

Allows for muscle attachments