Arthropods

Subphylum Mandibulata•Class Myriapoda•= chilopoda and diplopoda

Chilopods

~ 3,000 centipedes

Single pair of antennaePair of mandiblesEyes simple when present

Diplopoda~ 10,000 millipedes

Mostly deposit feeders in soilsome carnivores

2 pair legs per segment

Hexapoda = six-footed

•Class Insecta•Well-studied•Impacts on ag, pollination, disease vectors, commercial products

•~1,000,000 species described•4X more to be described

Insect taxonomy

Silverfish = Order Zygentoma

Subclass Pterygota = winged insects

Winged insectsOrder Ephemeroptera: mayflies

wings cannot be foldedadults live hours to few dayslarvae are aquatic

Winged insectsOrder Odonata = damselflies and dragonflies

wings cannot be foldedaquatic larvaepredators

Winged insects

Order Orthoptera = crickets, grasshoppersproduce noise by rubbing wings

Winged insects

• Order Plecoptera = stoneflies– Adults live only long enough to mate– Aquatic larvae, drumming behavior

Winged insectsOrder Hemiptera = true bugs

piercing mouthparts

Winged insectsOrder Coleoptera = beetles

front pair of wings form protective cover

Winged insects• Order Diptera = true flies– Posterior wings are reduced = halteres– Aquatic larvae in some

Winged insectsOrder Trichoptera = caddisflies

like small moths, feed on liquidsaquatic larvae = case-builders

Winged insects

• Order Lepidoptera = moths and butterflies– Larvae = caterpillars

Insect body

Head, thorax, abdomen

Insect head

•4 paired appendages:

•One pair antennae•Mandibles, maxillae, labium = lower lip

Insect thorax•Two pairs of wings•Reduced 2nd pair in diptera = halteres

Insect senses

•Tympanal organs = hearing•Compound eyes and ocelli

Gas exchange

Water balance

Insects produce uric acid from protein metabolites

Malpighian tubules

Insect development - instarsMetamorphosis

hemimetabolous = gradualholometabolous = larva – pupa -adult