Subphylum Uniramiacentipedes, millipedes, insects

Arthropoda Classification

Phylum ArthropodaSubphylum Uniramia- (terrrestrial mandibulates)

Class Chilopoda- centipedesClass Diplopoda- millipedesClass Insecta- insects

Subphylum Crustacea- (aquatic mandibulates) lobsters, crabs, crayfish, shrimp, sow bugs (pill bugs), krill and barnacles

Subphylum ChelicerataClass Arachnida- spiders, scorpions, ticks, and mitesClass Merostomata- horshoe crabClass Pycnogonida- sea spiders

Subphylum Trilobita- trilobites (extinct)

Class Chilopoda• Includes the centipede• 1 pair of legs per body segment• Flat body• Fast• Mainly carnivores (limbs on first

appendage are poisonous claws)

Class Diplopoda• Includes the millipede• 2 pairs of legs per body segment• Cylindrical Body• Slow• Mainly herbivorous

Arthropoda Classification

Phylum ArthropodaSubphylum Uniramia- (terrrestrial mandibulates)

Class Chilopoda- centipedesClass Diplopoda- millipedesClass Insecta- insects

Subphylum Crustacea- (aquatic mandibulates) lobsters, crabs, crayfish, shrimp, sow bugs (pill bugs), krill and barnacles

Subphylum ChelicerataClass Arachnida- spiders, scorpions, ticks, and mitesClass Merostomata- horshoe crabClass Pycnogonida- sea spiders

Subphylum Trilobita- trilobites (extinct)

Common Insect Orders

• Orthoptera- (“straight wing”) grasshoppers, crickets, cockroaches, locusts, katydids

• Hemiptera- (“half wing”) true-bugs, stinkbugs, bed bugs, water striders

• Coleoptera- (“sheath wing”) beetles, weevils• Lepidoptera- (“scale wing”) butterflies, moths• Hymenoptera- (“membranous wing”) bees,

ants, wasps, sawflies• Diptera- (“two wings”) flies, mosquitoes, gnats

Order Orthoptera Order Odonata

Order Coleoptera

Order Lepidoptera

Order Hymenoptera

Order Diptera

Class Insecta

Important characteristics for survival:

1. They can fly A. Escape danger B. Find a mate C. Look for food D. Search for suitable

environment

2. They have tremendous reproductive capabilities

• Can produce thousands of eggs in a single day

3. They have great variety within the class. They are specialized to occupy different niches.

Niche(1) The specific area where an organism inhabits. (2) The role or function of an organism or species in an ecosystem. (3) The interrelationship of a species with all the biotic and abiotic factors affecting it.

• Little competition for food• Little competition for living space

Basic Insect Structure

The following characteristics distinguish insects from other arthropods

• Three pairs of walking legs• Wings usually present• Body divided into 3 segments (head, thorax, abdomen)• One pair of sensory antennae

Legs

• Fly (Order Diptera) legs have tiny claws and sticky pads for climbing smooth surfaces

• Grasshopper (Order Orthoptera) heavily muscled hind legs for jumping

• Bees (Order Hymenoptera) have combs and hairs on their legs- important for carrying pollen

Wings

• Membranous wings- thin, transparent, contain supporting veins, flying wings of most insects, both pairs of wings in Order Hymenoptera are membranous

• Scale covered wings- both pairs in butterflies and moths (Order Lepidoptera)

• Leatherlike wings- grasshopper (Order Orthoptera) has flying wings covered by leatherlike wings that protect the flying wings

• Horny wings (elytra)- thick hard shields that protect the flying wings of beetles (Order Coleoptera)

• Order Hemiptera only have 1 pair of wings and half the wing is leatherlike and the other half is membranous

Mouthparts

The development of insect mouthparts from the primitive chewing mouthparts of a grasshopper in the centre (A), to the lapping type (B) of a bee, the siphoning type (C) of a butterfly and the sucking type (D) of a female mosquito.

•Labrum- upper lip•Labium- lower lip•Mandibles- chewing appendages•Maxillae- manipulate food when eating•Palps- sensory appendages•Proboscis- coiled tube, in Order Lepidoptera used to siphon nectar from flowers•Rostrum- long beak that folds under the insects body in Order Hemiptera used to pierce food

Legend: a, antennaec, compound eyelb, labiumlr, labrummd, mandiblesmx, maxillaehp, hypopharynx

Digestion• Mouth• Esophagus• Crop• Gizzard• Stomach• Intestines• Anus

Foregut

Midgut

Hindgut

Salivary glands- secretions from these moisten food in the mouth

Gastric ceca- pouchlike organs that surround the stomach and supply it with digestive juices

Respiration

• Tracheal system- series of tubules that run throughout the insects body and open to the outside through pores called spiracles, this system is sufficient itself for respiration

Circulation and Excretion

• Tubular heart• Hemolymph- clear or yellowish fluid in insects,

carries nutrients and waste• Open circulatory system• Malpighian tubules- ring of thin tubules

encircling the juncture of the stomach and intestine, extract nitrogenous wastes from hemolymph and pass them into the intestine so they can be excreted

Response

• Antennae- smell• Mouthparts have taste receptors• Hairs all over the body sense touch• Compound eyes- usually large relative to the head,

large field of view• Grasshoppers (Order Orthoptera) have a tympanum

which is a membrane covered chamber in the first abdominal segment that allows them to hear.

• Stridulation- producing sound by rubbing body parts together

Reproduction• Sexual reproduction• Not hermaphroditic• Females have an ovipositor which is a pointed

extension at the end of the abdomen, deposits fertilized eggs

Metamorphosis-series of developmental changes.

1. Incomplete metamorphosis-involves 3 basic stages 1. Egg 2. Nymph (naiad if in water) 3. Adult

Orthoptera, Hemiptera

2. Complete metamorphosis- involves 4 stages 1. Egg 2. Larva 3. Pupa 4. Adult

Process followed by 90% of all insectsColeoptera, Lepidoptera, Hymenoptera, Diptera

Larva (common names)

• Maggots- flies• Grubs- beetles• Wigglers- mosquitoes• Caterpillars- moths and butterflies

Incomplete Metamorphosis