to “bugs”

An Introduction

to “Bugs”

Whitney Cranshaw

Colorado State University

Arthropod Features

• Segmented body

• Exoskeleton

• Jointed appendages

• Bilateral symmetry of design

• Dorsal heart/Ventral nerve cord

Arthropod Characteristics

Segmented bodies

Phylum Arthropoda

Arthropods

Arthropod Characteristics

Segmented bodiesExternal Skeleton

(Exoskeleton)

Features of the Insect Exoskeleton

Protection from:

-Pathogens

-Physical trauma

-Insecticides, etc.

Eleodes darkling

beetles

(aka “stink beetles”.

“skunk beetles”,

“circus beetles”)

Primary advantage of an exoskeleton:

Provides a means for small animals to avoid

excessive water loss!

Allows for development of:

-Appendages

Features of the Insect Exoskeleton

Mobility is enhanced.

Allows for development of:

-Appendages

-Specialized structures

Features of the Insect Exoskeleton

Enhance feeding, defense,

movement

Allows for development of:

-Appendages

-Specialized structures

-Arthropod tracheal system of

gas exchange

Features of the Insect Exoskeleton

Decreased water loss

The exoskeleton allows

for development of the

arthropod tracheal system

allowing transport/

exchange of oxygen to

cells

Spiracles

The tracheal

system transports

oxygen to each cell

Spiracle

Disadvantage of an exoskeleton:

9:11

10:36

11:42

Darkening of a recently

molted lady beetle adult

Soft Shell vs. Hard

Shell Lobster Meat

Extraction Trial

July 2015

Soft shell Hard shell

Meat Extraction Soft Shell vs. Hard Shell

Water Component Soft Shell vs. Hard Shell

Soft shell Hard shell

Arthropod Characteristics

Segmented bodiesExternal Skeleton

(Exoskeleton)

Jointed

appendages

Arthropod Characteristic

Body plan is

bilaterally

symmetrical

Incorrect

I YOU

A Cricket’s Valentine

Arthropod Features

• Segmented body

• Exoskeleton

• Jointed appendages

• Bilateral symmetry of design

• Dorsal heart/Ventral nerve cord

Classes of

Arthropoda

Crustaceans

Arthropod Class

Terrestrial Isopods*

(Sowbugs and Pillbugs)

*Subphylum Crustacea ; Class Malacostraca; Order

Isopoda

Crustacean Features

• Two pair of

antennae

• Distinct head area

• Body usually

covered by a shield

like carapace

• Oxygen acquired

through gills

Seven pairs of legs Mouthparts

Immature stages of sowbugs and

pillbugs are similar in features as

the adults, but smaller – a simple

type of metamorphosis

Sowbug

Molting

Front half molts first

Back half molts second

Molting occurs in

two stages with the

sowbugs and

pillbugs

Sowbugs and

Pillbugs

Sowbug

Pillbug – also known as the ‘roly-poly’

Associated with moist

areas and decaying

vegetation

Sowbugs

Pillbug (a.k.a.

“roly-poly’)

Sowbugs

Now if only I

could roll

into a ball…

Pillbug

Arthropod Class

Diplopoda

Millipedes

Millipedes

Two Pairs of Legs Per Segment

Millipede Feature –Two pairs of legs per

segment

Duff Millipedes

Arthropod Class

Chilopoda

Centipedes

1 Pair Antennae

1 Pair Legs/

Body Segment

Centipedes

Most

centipedes

have 15 to 23

pairs of legs

Head

Pseudohead

Centipedes

Maxillipeds

Prey is captured with the

maxillipeds and are injected

with a toxin (cytolysin)

Stone Centipede – A common garden resident

House Centipede

Orders of

Arachnids

Arachnid Feature – Two Body Regions

Cephalothorax

Abdomen

Arachnid Feature – Four Pairs of Legs

Chelicerae

Face of a longjawed spider showing chelicerae and pedipalps

PedipalpsPhoto courtesy of Brian Valentine

Spiders Order Araneae

Some spiders use

webbing to snare prey

Some spiders

hunt prey without

the aid of silk

David Cappaert

Brian Valentine

The Wood Louse

Hunter/ Roly-Poly

Killer

Family Dysderidae

~Dysdera crocata

Daddy longlegs, Harvestmen

Order: Opiliones

Mites & Ticks Order Acari

Ticks feed on the blood of

vertebrates

Left: Before Below: After

Scorpions Order Scorpiones

Pedipalps (chelae)

for prey capture

Scorpion chelicerae (jaws)

Scorpions

fluoresce in

ultraviolet

light

Scorpions fluorescing

under black light

An adorable baby scorpion!

Common

striped bark

scorpion

Centruroides vittatus

Northern scorpion

Northern desert

hairy scorpion

Scorpions of

Western Colorado

Photograph by Bob Hammon

Windscorpions, Sunspiders,

Solpugids

Order Solifugae

Photograph by Mike Gittleson

Photograph by Frank Peairs

Courtesy University of California

The notorious “camel spider” photograph

Orders of Insects

Segmented

Body

External skeleton/

Exoskeleton

Jointed

Appendages

Arthropod Characteristics

Abdomen Thorax Head

Insect body is

organized into

three regions

Academy Award

Nominee (1955) for

Special Effects

Special/Visual

Effects Academy

Award

1955 Nominee

2019 WinnerThe movie 1917

won the award

this year

Head

Thorax Abdomen

Three pairs of legs – on the thorax

A Jerusalem cricket – an insect of unusual

appearance found in western Colorado

Larvae of Lepidoptera,

known as caterpillars,

have 2-5 pairs of

abdominal prolegs

The prolegs are tipped

with hook-like crochets

Lepidoptera larvae (caterpillars) have prolegs on

the abdomen

Inchworms and loopers have only 2 or 3 pairs of prolegs

Whitelined sphinx (Hyles

lineata) – The common

“hummingbird moth” of

the western US

Orders of Insects

The Real Transformers - Insecticon

How Many Kinds of Insects

Are There on Earth?

• Approximately 1 million different

insect species have been described

• It is estimated that there presently

exist probably 4-6 million species of

insects; some estimates are higher

• New species of insects are described

at a rate of about 7200/year

Metamorphosis

‘Change in form’

A simple, or gradual pattern of metamorphosis

Green peach aphid giving

live birth to daughter

Cannabis aphid

mother and daughters

(genetically identical)

Mosquito Life Cycle

Adult (left)

Larvae/wrigglers (lower left)

Pupae/tumblers (below)

What Should We Cover?

• Aphids

• Hummingbird Moths

• Whiteflies

• Slugs

• Earwigs

• Wood borers (incl.

Emerald ash borer)

• Bark beetles/Ips

• Japanese beetle

• Scale insects

• Spider mites

• Gall insects

• Nuisance invaders

• Grasshoppers

• Codling Moth

• Flea beetles……….

Next up:

Natural

Enemies of

Insect

Pests