Transcript What are insects - The Ohio State University

Entomology 462
Arthropod Groups
David J. Shetlar, Ph.D.
The “BugDoc”
The Ohio State University,
OARDC & OSU Extension
Columbus, OH
© October, 2001, D.J. Shetlar, all rights reserved
What is Entomology?
The study of insects
(and their near relatives).
What are insects
(and near relatives)?
Insects and their relatives are
ARTHROPODS.
Review of Zoological Nomenclature
(classifying & naming)
Taxonomic Categories
Phylum
Class
Order
Family
Genus
Genus & species
Review of Zoological Nomenclature
Taxonomic Categories
Kingdom - Animalae
Phylum - Arthropoda
Class - Insecta
Order - Coleoptera
Family - Scarabaeidae
Genus - Popillia
Genus & species
Popillia japonica Newman
Characteristics of the Phylum
Arthropoda
The segmented bodies are arranged into
regions, called tagmata (e.g., head, thorax,
abdomen).
The paired appendages (e.g., legs, antennae)
are jointed.
They posses a chitinous exoskeletion that
must be shed during growth.
They have bilateral symmetry.
The nervous system is dorsal (belly) and the
circulatory system is open and ventral (back).
What are some other
Animal Phyla?
Protozoa - single-celled animals.
Platyhelminthes - flatworms, tapeworms
Nematoda - roundworms
Mollusca - clams, snails & slugs, squids
Echinodermata - starfish, sea urchins
Annelida - segmented worms (earthworms)
Chordata - fish, amphibians, reptiles, birds,
mammals
Arthropod Groups (taxa)
The arthropods are divided into two
large groups that exist today:
The Chelicerates
and
The Mandibulates
Chelicerate Arthropod Characters:
Pincher-like mouthparts chelicerae - and pedipalps
NO antennae
Two body regions, usually cephalothorax & abdomen
Four pairs of legs
Horseshoe crabs and arachnids
are only living groups
Mandibulate Arthropod Characters:
Mouthparts are mandibles normally chewing sideways
One or two pairs of antennae
Various body region arrangements cephalothorax & abdomen / head &
trunk / head, thorax & abdomen
Variable leg numbers
Insects, crustaceans & myriapods
Orders of Arachnids
Scorpionida - scorpions
Pseudoscorpionida - false
scorpions
Opiliones - daddy-long-legs or
harvestmen
Acari - mites & ticks
Araneida - spiders
Pseudoscorpion
Scorpion
Daddy-long-legs
Tick
(a mite)
Wolf
Spider
Scorpion Anatomy
chelicerae
eyes
pedipalp
Pseudoscorpion
Mite and Tick Body Regions
pedipalps &
chelicerae
cephalothorax
abdomen
American dog tick male
Blacklegged (deer) tick female
American dog tick female laying egg mass (1000-2000 eggs!).
Clover mites
Twospotted spider mites
Predatory mite
Opiliones [=Phalangida]
daddy-long-legs
cephalothorax
abdomen
Spider Anatomy
pedipalp
chelicera (fang)
cephalothorax
narrow waist
abdomen
Jumping Spider
Abdomen
Cephalothorax
Chelicera (fang)
Pedipalp
Wolf spider with egg case
Tarantula
Spitting spider
Orbweaving spider
Black widow with egg case
Brown recluse
(fiddleback)
Classes of Myriapods
(many legged arthropods)
(all have one pair of antennae, a head region, and trunk
with many pairs of legs, use trachea)
Diplopoda - millipedes
Chilopoda - centipedes
Symphyla - garden centipedes
Myriapods
[one pair of antennae, head & trunk regions, trunk with many pairs of legs]
Millipede (Diplopoda)
Two pair of legs per visible segment, attached
under body.
Centipede (Chilopoda)
Pair of fangs under head, one pair legs per visible
segment - attached to side of body.
Symphylan (Symphyla)
[garden centipede]
No fangs, no eyes, legs attached to side of body.
Millipede (Diplopoda)
Centipede (Chilopoda)
Garden centipede (Symphyla)
Classes of Crustacea
(mostly marine, fresh water, a few terrestrial)
(all have two pair of antennae, five or more pairs of legs,
segmented abdominal appendages, head & trunk or
cephalothorax & abdomen body arrangement, have gills)
Isopoda - sowbugs or pillbugs
Amphipoda - sand fleas, amphipods
Cirripedia - barnicles
Decapoda - crabs, lobster, shrimp
several other minor orders
Crayfish cephalothorax
(Decapoda)
Sowbug (Isopoda),
a terrestrial crustacean