Introduction to Insects Entomology Training for Master Gardeners

THE 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...

Arthropoda (“jointed leg”) Insects are in the phylum Arthropoda (“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 insects world-wide

Over 13,000 species of insects known from Florida New species appear almost daily due to shipments of plants and other materials into Florida from abroad

Beneficial or just co-exist (> 99%) Less than 1% Considered to be pests Of all insect species in the world

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 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 from 2nd and 3rd segment.

The Abdomen is responsible for excretion and reproduction.

Growth and Develoment Metamorphosis - 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 Feed Insects can be separated by the type of mouthparts they possess which dictates the type of job they have.

Most common type of mouthpart is chewing. Tear off pieces of tissue and eat it.

Plant damage caused by pests with chewing mouthparts

Some common yard and garden pests with chewing mouthparts

Immature beetles “Skeletonizing” damage caused by immature chewing insects

Another common type of mouthpart is piercing/sucking (This is a good bug)

Plant damage caused by pests with piercing/sucking mouthparts

Whiteflies – Bad insects

A 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 (?)

Aphids

Some Things That Eat Aphids (Good Insects) Lady Beetles- eggs, adult, pupae, and larvae

Lacewing - eggs and adult Lacewing larvae

Aphid Mummies Parasitic Wasps

Mole Crickets

Mole Cricket Damage

Tropical Sod Webworm

Chinch Bugs

Earwig Enemies of Lawn Pests Rove Beetles Big-eyed Bug

Stinkbugs Note spines on thorax Green Stinkbug - Bad Predatory Stinkbug - Good

Predaceous Stinkbug Parasitic wasps

Leafminers – Feed within the leaf Serpentine Leaf Miner Citrus Leaf Miner

(Note: Black dots of excrement on leaf undersides) Lacebugs

Southern Pine Beetle – Tree boring Beetle Leaf-eating Beetles

Thrips Rasping-sucking mouthpart

Mealybugs UF - IFAS

Twospotted Spider Mite

Spider-Mite Webbing UF - IFAS

Predatory Mite (eats bad mites)

Armored Scales: Florida Red Scale UF, IFAS

Scale Insects

Asian Cycad Scale

Soft Scale: Green Scale UF - IFAS

Scale predators and parasites Lady Beetle Species

Parasitic Wasps

Adapted by Jim Price from: Author: Tom Weissling, University of Florida Photos: University of Florida University of Nebraska University of California Entomology And Nematology Department Copyright University of Florida 2000 For more detailed information see the Featured Creatures WWW site at