Introduction to InsectsIntroduction to Insects

Entomology TrainingEntomology Trainingfor for

Master GardenersMaster Gardeners

THE INSECTSTHE INSECTS

• Fossil records indicate insects on land more than 300 million years ago

Insects are from an ancient lineage that included trilobites and other arthropods which were abundant in the oceans over 500 million years ago.

but we are surrounded by other arthropods.

Trilobites are extinct...

Insects are in the phylum Arthropoda Arthropoda

(“jointed leg”)(“jointed leg”) The phylum is divided into 6 smaller groups called classes:

Crustacea (crabs, lobsters, shrimps) Chilopoda (centipedes) Diplopoda (millipedes) Symphyla (symphylans) Arachnida (spiders, mites)

Insecta (insects)

All arthropods share the following characteristics:1) Arthropods have a segmented body

2) All arthropods have paired, jointed legs

3) All arthropods have a chitinous exoskeleton (which is periodically shed and renewed as the animal grows)

University of Nebraska-Lincoln, Department of Entomology, Leon Higley

4) All arthropods have a digestive system (tube that runs from head to tail)

5) All arthropods have an “open” circulatory system, no veins, arteries etc. Blood is held in a dorsal tubular structure with lateral openings in the abdomen.

6) All arthropods have a ventral nervous system which consists of a tiny brain, paired nerve cords which extend from the brain backward, and nerve centers called ganglia.

7) All arthropods breathe by means of gills, or tracheae and spiracles.

8) Separate sexes (nearly always)

The Class Crustacea (lobster, shrimp, crab, pillbugs, etc.) have two pairs of antennae and at least five pairs of legs.

Yummy!

The classes Chilopoda, Diplopoda, and Symphyla (centipedes, millipedes, etc.) have antennae,many legs and only two body regions.They add segments as they molt.

The class Arachnida have 8 legs and no antennae. They are in a group of Arthropods that diverged from the insects in the mid-paleozoic.

The Class Insecta

Kingdom: Animalia

Phylum: Arthropoda

Class: Insecta

(Class: Arachnida)

At least half (50%-80% [?]) of the animal species currently occupying the earth are insects

(approximately 1.5 million different animal species)

More than 1 million species of More than 1 million species of insects world-wideinsects world-wide

Over 13,000 species of Over 13,000 species of insects known from Floridainsects known from Florida

New species appear almost daily due toNew species appear almost daily due toshipments of plants and other materialsshipments of plants and other materials

into Florida from abroadinto Florida from abroad

Beneficial or just co-exist(> 99%)

Less than 1%Less than 1%Considered Considered to be peststo be pests

Of all insect species in the world

Relation of insects to humans:Relation of insects to humans:

1. Beneficial: Pollination, break down raw materials, aerate soil, bio-control of weeds and bad bugs, food for many animals, medical uses.

2. Aesthetic Value: Butterflies

3. Injurious: Feed on plants, stored foods, woods, fabrics, humans, and animals

The InsectsThe Insects

1. Three, usually distinct body regions (head, thorax, and abdomen)

2. One pair of segmented antennae

3. Usually have one pair of compound eyes

4. Three pairs of legs

5. Two pair of wings usually (some have only one pair (i.e., flies) or no wings at all).

The Head. Functions mainly for feeding and sensory perception.

The Thorax. Responsible for locomotion. Made up of 3 segments. A pair of legs arise from each segment. Wings, if present, arise from2nd and 3rd segment.

The Abdomen is responsible for excretion and reproduction.

Growth and DevelomentMetamorphosis - The process of change from egg to adult.Incomplete or gradual metamorphosis. Baby insects (nymphs) look similar to adults (grasshoppers, aphids, cockroaches). Growth occurs through molting.

Complete metamorphosis. Larvae look nothing like adults. The larvae pass through a pupal stage to change into the adult form (wasps, beetles, moths, butterflies, flies).

How Insects FeedHow Insects Feed

Insects can be separated by the typeInsects can be separated by the typeof mouthparts they possess which of mouthparts they possess which dictates the type of job they have.dictates the type of job they have.

Most common typeMost common typeof mouthpart isof mouthpart ischewingchewing..

Tear off pieces ofTear off pieces oftissue and eat it.tissue and eat it.

Plant damage caused by Plant damage caused by pests with chewing mouthpartspests with chewing mouthparts

Some common yard and garden pestsSome common yard and garden pestswith chewing mouthpartswith chewing mouthparts

Immature beetles

“Skeletonizing” damage caused by immature chewing insects

Another common type of mouthpart isAnother common type of mouthpart ispiercing/suckingpiercing/sucking

(This is a good bug)

Plant damage caused by Plant damage caused by pests with piercing/sucking mouthpartspests with piercing/sucking mouthparts

Whiteflies – Bad insectsWhiteflies – Bad insects

A few good bugs that eat whitefliesA few good bugs that eat whiteflies

Minute Pirate Bug

Big-eyed Bugs

Some specific insects Florida Master Gardeners should know …

Orange Dog Caterpillar – Bad insect (?)Orange Dog Caterpillar – Bad insect (?)

Aphids

Some ThingsSome ThingsThat EatThat EatAphidsAphids

(Good Insects)(Good Insects)

Lady Beetles- eggs, adult, pupae, and larvae

Lacewing - eggs and adult

Lacewing larvae

Aphid MummiesAphid Mummies

Parasitic Wasps

Mole CricketsMole Crickets

Mole Cricket DamageMole Cricket Damage

Tropical Sod WebwormTropical Sod Webworm

Chinch BugsChinch Bugs

Earwig

Enemies Enemies of Lawn of Lawn PestsPests

Rove Beetles

Big-eyed Bug

StinkbugsStinkbugs

Note spines on thorax

Green Stinkbug - Bad

Predatory Stinkbug - Good

Predaceous Stinkbug

Parasitic wasps

Leafminers – Feed Leafminers – Feed withinwithin the the leafleaf

Serpentine Leaf Miner

Citrus Leaf Miner

(Note: Black dots of excrement on leaf undersides)

LacebugsLacebugs

Southern Pine Beetle – Tree boring Beetle

Leaf-eating Beetles

ThripsThripsRasping-sucking Rasping-sucking

mouthpartmouthpart

MealybugsMealybugs

UF - IFAS

Twospotted Spider Mite

Spider-Mite Webbing

UF - IFAS

Predatory Mite (eats bad mites)

Armored Scales: Florida Red Scale

UF, IFAS

Scale InsectsScale Insects

Asian Cycad Scale

Soft Scale: Green ScaleSoft Scale: Green Scale

UF - IFAS

Scale predatorsScale predatorsand parasitesand parasites

Lady Beetle Species

Parasitic Wasps

Adapted by Jim Price from:Author: Tom Weissling, University of FloridaPhotos: University of Florida

University of NebraskaUniversity of California

Entomology And Nematology Department

Copyright University of Florida 2000

For more detailed information see the Featured Creatures WWW site at http://www.ifas.ufl.edu/~insect/