Our hard-shelled friends…..and foes! Arthropods Our hard-shelled friends…..and foes!

Characteristics of Arthropods Segmented Jointed appendages Hard external skeleton 3 parts-head, thorax, abdomen (arachnids exception) Exoskeleton-hard, external skeleton made of chitin Molting- shed old exoskeleton and secrete a larger one, very vulnerable after molting

Body parts Ganglia-clusters of nerve cells along a nerve cord Compound eyes-may facets each with their own lenses, some have single lenses and some have both Spiracles-holes in the exoskeleton that allow gas exchange (book lungs in arachnids) Trachea-chitin lined tubes in spiracles

Arthropod Ancestors-Trilobites

Diversity of Arthropods First arthropods evolved in sea about 560 mya 4,000 species of trilobites Spider-like arthropods abundant in sea 300 mya, only 4 species left-horseshoe crabs-changed very little Crustaceans live in mostly aquatic environments, specialization of appendages;claws

Types Crustaceans-lobsters, crayfish, crabs, shrimp, barnacles, copepods, Isopods (pillbugs,sowbugs) Arachnids-spiders, scorpions, mites and ticks Insects-beetles, ants, grasshoppers, butterflies, dragonflies,etc Myriapods- centipedes-venomous, millipedes- toxic chemicals, smell/taste bad

Class Arachnida Scorpions, spider, ticks, mites 2 body sections-cephalothorax and abdomen Chelicerae-fanglike mouthparts to paralyze prey with poison Pedipalps-mouthpart typically used to manipulate prey once it has been paralyzed or for mating Malpighian tubules-remove wastes from fluids in body cavity

Arachnids Book lungs-specialized respiratory structures and provide large surface for gas exchange, some use trachea Almost all arachnids live on land and have several adaptations to help them retain water.

Types Spiders-have silk glands made from spinnerets; many hunt for prey or use webs Scorpions-nighttime hunters in deserts, venomous stinger at the end of the tail, body glows in a black light Mites/ticks-suck sap or blood, sucking mouthparts, transmit diseases, Lyme disease, Rocky Mountain spotted fever, tick paralysis

Spiders

Not really spiders but close…

Scorpions All scorpions glow in a black light

Mites and Ticks

Class Crustacea Decapods-ten legs, pincers and walking legs, most are marine, crayfish are freshwater and a few land crabs exist in tropical areas 2 body parts-cephalothorax and abdomen Carapace-portion of the exoskeleton that cover cephalothorax Mandibles-bite and grind food Lobsters, crayfish, crabs, shrimp

Barnacles and Copepods Barnacles secrete calcium carbonate to make their shells Copepods are very small but play a big part in food chains

Isopods Most are small marine crustaceans, but also include large animals and terrestrial pillbugs/sowbugs

Decapods

Isopods

Barnacles and Copepods

Class Insecta 3 main body parts-head, thorax, abdomen 6 walking legs Wings Malpighian tubules for waste Tracheal system and spiracles for gas exchange Young often have completely different behavioral and eating patterns in complete metamorphosis Entomology-study of insects

Class Insecta-Complete Metamorphosis Changes from one completely different form into another adult form. Has various stages of larva and pupa before becoming an adult Pupa is an inactive stage in which a cocoon forms and the insect undergoes major physical and chemical changes. Examples are: butterflies, moths, wasps, bees, beetles

Class Insecta-Incomplete Metamorphosis Insect goes through various stages of molting and growing but remain basically the same. Young grows bigger and bigger but has same feeding habits and physical appearance Examples are: praying mantis, crickets and grasshoppers

Class Insecta Includes Many Insect Orders Coleoptera- beetles Lepidoptera-butterflies and moths Diptera- flies and mosquitoes Hymenoptera- ants, bees, wasps Hemiptera- the true “bugs” stinkbugs, water striders Orthoptera- crickets and grasshoppers Odonata- dragonflies and damselflies Isoptera- Termites Homoptera- cicadas, aphids

Order Coleoptera Larval Beetle Forms

Order Lepidoptera Larval Forms

Order Diptera

Maggots, Diptera Larvae

Order Hymenoptera

Order Hemiptera The Kissing Bug, transmits the deadly Chagas disease!

Order Orthoptera

Order Odonata Larval Forms

Order Homoptera Molted skin

Cicada Songs Many of these are from the Southeast Asia areas, but there are cicadas that are quite loud around here.

Order Isoptera Termite Queen