insect structure. why study? an understanding of the external structure of the an understanding of...
TRANSCRIPT
Why Study? Why Study? • An understanding of the external structure An understanding of the external structure of the of the insect is necessary…insect is necessary…
- to allow the identification of insects and - to allow the identification of insects and other arthropodsother arthropods
- to understand their biology and control- to understand their biology and control
ExoskeletonExoskeleton
• Outer layer or “skin”Outer layer or “skin”
• Functions:Functions: - Protection of soft parts- Protection of soft parts - Muscle attachment- Muscle attachment - Support- Support - Site for sensory organs- Site for sensory organs - Helps prevent desiccation- Helps prevent desiccation - Reduces pathogen entry- Reduces pathogen entry
Components of the Components of the ExoskeletonExoskeleton
• CuticleCuticle - non-living- non-living
• EpidermisEpidermis- living- living- secretes the cuticle- secretes the cuticle
• Basement membraneBasement membrane- non-living- non-living- function not known- function not known
CuticleCuticle• Key contributor to the success of insectsKey contributor to the success of insects
- barrier between living tissue/environment- barrier between living tissue/environment- restriction of water loss- restriction of water loss- abrasion protection- abrasion protection
endocuticle
exocuticle
waxcement
epic
uti
cle
cuticle
Body StructureBody Structure
3 body regions 3 body regions
1 pair of antennae1 pair of antennae
3 pair of legs on the thorax3 pair of legs on the thorax
HeadHead
ThoraxThorax
AbdomenAbdomen
HeadHead• Functions:Functions:
- Mouthparts (feeding appendages)- Mouthparts (feeding appendages)
- Sensory organs (interaction with nature)- Sensory organs (interaction with nature)
- photoreceptors/vision- photoreceptors/vision- receptors on antennae- receptors on antennae
- Houses the brain- Houses the brain
AntennaeAntennae
• Single pair Single pair
• Located between and in front of eyesLocated between and in front of eyes
• Sensory function Sensory function - touch- touch- smell- smell- humidity- humidity- sound- sound
VisionVision
• Compound eyes Compound eyes - main organ of vision- main organ of vision
• Composed of individual units - ommatidia Composed of individual units - ommatidia - each registers a portion of a mosaic image- each registers a portion of a mosaic image- number vary (>25,000 for dragonflies)- number vary (>25,000 for dragonflies)- surface of eye is protected with a cuticle- surface of eye is protected with a cuticle
• Resolution of image variesResolution of image varies
- dragonfly: several meters away- dragonfly: several meters away- other insects: only a meter or so away- other insects: only a meter or so away
How do insects perceive How do insects perceive the world?the world?
• Many can see color (but many blind to red)Many can see color (but many blind to red)
• Others see colors we can not - UltravioletOthers see colors we can not - Ultraviolet
• Some only detect degrees of light and no imageSome only detect degrees of light and no image
• Others are totally blindOthers are totally blind
Nectar GuidesNectar Guides
• Many insect-pollinated flowers have nectar Many insect-pollinated flowers have nectar guidesguides
• Serve as visual guides to direct insects to nectar Serve as visual guides to direct insects to nectar sourcesource
• Nectar guides absorb UV lightNectar guides absorb UV light
• Rest of flower reflects UV lightRest of flower reflects UV light
MouthpartsMouthparts
• Basic types:Basic types:
- chewing- chewing - sponging- sponging- piercing-sucking- piercing-sucking - siphoning- siphoning- rasping-sucking- rasping-sucking - chewing-lapping- chewing-lapping
• Important for insect identificationImportant for insect identification
• Provides information on feeding habits Provides information on feeding habits and types of damageand types of damage
Chewing TypeChewing Type• Simplest typeSimplest type
• Used to chew holes in leaves, bore in stemsUsed to chew holes in leaves, bore in stems
• Examples: grasshoppers, crickets, Examples: grasshoppers, crickets, caterpillars, beetlescaterpillars, beetles
Piercing-Sucking TypePiercing-Sucking Type
• Common and important typeCommon and important type
• Greatly modified for puncturing Greatly modified for puncturing plants and animalsplants and animals
• Mouthpart components form needle-like styletsMouthpart components form needle-like stylets
• Capable of transmitting virusesCapable of transmitting viruses
• Toxic salivaToxic saliva
• Examples: mosquitoes, stink bugs, etc.Examples: mosquitoes, stink bugs, etc.
Rasping-Sucking TypeRasping-Sucking Type
• Combination of chewing and piercing-suckingCombination of chewing and piercing-sucking
• Rasp (scrap) surfaces of leave, suck up sapRasp (scrap) surfaces of leave, suck up sap
• Example: thripsExample: thrips
Sponging TypeSponging Type
• Modified for liquids or solid foodsModified for liquids or solid foods- solid foods must be dissolved by salivary - solid foods must be dissolved by salivary secretionssecretions
• Example: house flyExample: house fly
Siphoning TypeSiphoning Type• Mouthparts form a sucking tube (proboscis)Mouthparts form a sucking tube (proboscis)
- modified for uptake of nectar/liquids- modified for uptake of nectar/liquids
• Coiled beneath head when not in useCoiled beneath head when not in use
• Examples: butterflies and mothsExamples: butterflies and moths
Chewing-Lapping TypeChewing-Lapping Type
• Modified to use liquid or semi-liquid foodsModified to use liquid or semi-liquid foods
• Some mouthpart components function for chewingSome mouthpart components function for chewing- mold wax- mold wax- grasping prey- grasping prey- cutting flowers- cutting flowers
• Other components form the proboscisOther components form the proboscis- ‘lapping’ surface- ‘lapping’ surface
• Examples: honey bee, bumble beeExamples: honey bee, bumble bee
ThoraxThorax
• Divided into 3 regionsDivided into 3 regions- prothorax- prothorax- mesothorax- mesothorax- metathorax- metathorax
• Main function: locomotionMain function: locomotion - walking/running- walking/running - jumping- jumping - swimming- swimming - flying- flying
LegsLegs
• Three pairs of true legsThree pairs of true legs
• 6 basic segments of the leg6 basic segments of the leg- coxa- coxa- trochanter- trochanter- femur- femur- tibia- tibia- tarsus- tarsus- pretarsus- pretarsus
• Adapted for various functionsAdapted for various functions
Types of LegsTypes of Legs
• Cursorial – runningCursorial – running
• Fossorial – diggingFossorial – digging
• Raptorial – predaceousRaptorial – predaceous
• Saltatorial – jumpingSaltatorial – jumping
• Natatorial - swimmingNatatorial - swimming
WingsWings
• Number of wings varies by speciesNumber of wings varies by species- 2 pairs - 2 pairs - 1 pair on the mesothorax- 1 pair on the mesothorax- absent- absent
• FunctionsFunctions - locomotion- locomotion - protection- protection - camaflouge- camaflouge
Types of WingsTypes of Wings• MembranousMembranous
• Elytra - Elytra - hardened, front wings hardened, front wings that serve as protective covers that serve as protective covers for membranous hind wings for membranous hind wings
• Hemelytra - Hemelytra - front wings that are front wings that are leathery or parchment- leathery or parchment- like at the base and like at the base and membranous near the tip membranous near the tip
• Halteres - Halteres - small, club-like hind wings small, club-like hind wings that serve as gyroscopic that serve as gyroscopic stabilizers during flight stabilizers during flight
• ScalesScales
• Tegmina - Tegmina - front wings that are front wings that are completely leathery or completely leathery or parchment-like in texture parchment-like in texture
AbdomenAbdomen• Functions:Functions:
- respiration- respiration
- excretion- excretion
- reproduction- reproduction
AbdomenAbdomen• SpiraclesSpiracles
- openings involved in respiration- openings involved in respiration
- located on each side of abdomen- located on each side of abdomen
• CerciCerci - sensory organs- sensory organs
• OvipositorOvipositor - egg-laying structure- egg-laying structure - stingers (modified ovipositor- stingers (modified ovipositor
found in some females)found in some females)