Arthropods insects

Taxonomy Arthro- = joint Pod = foot Examples: spiders, insects, shrimp, lobster, crabs, millipedes, centipedes

General Characteristics The largest group of animals Have a hard exoskeleton made out of chiton Have jointed appendages for a wider range of motion Air is piped directly to cells for higher metabolism Demonstrate complex behavior patterns based on instinct

Body Plan Body Plan: Jointed appendages, segmented body, bilateral symmetry and exoskeleton made of chiton for protection Exoskeleton: hard outer covering that is sometimes molted exoskeleton molting horseshoe crab

Body Plan Segmentation: internally and externally segmented Each segment contains spiracles and nerves Head-thorax-abdomen or cephalothorax-abdomen Jointed appendages: jointed legs allow for more advanced movement and modification for a wider range of habitats Coelom: true body cavity filled with hemolymph (blood- like fluid)

Respiration Respiration: (spiracles) a system of air tubes that deliver oxygen directly to cells

Digestion Digestion: complete digestive system with specialized mouth parts and appendages (mandibles and palps) specialized for each food source

Circulation Circulation: Open circulatory system with a heart, arteries and hemolymph Hemocoel: the cavity that holds hemolymph fluid

Nervous System Nervous System: brain, nerve cords, ganglia and specialized sensory organs

Movement Movement: each arthropod has appendages that are specialized

Reproduction Reproduction: sexual reproduction: sexes are separate Fertilization is internal and then eggs are laid

Metamorphosis Metamorphosis: the changes in form that occur in an insects life cycle Incomplete: larva-nymph-adult Complete: larva-cocoon-adult butterflies

Ecological Importance Essential in food webs because they occupy every area on Earth Essential in the pollination of many plants Spread diseases (mosquitos, ticks) Create products like honey, silk and beeswax Are a food source for humans insect dye

Class Merostomata Only five living species Live in oceans but can swim up rivers Can spend time out of water Most ancient living arthropods Examples: horseshoe crabs

Horseshoe Crabs

Class Pycnogonida Number of legs varies from 8-12 Found in all oceans and all temperatures Examples: Sea spiders

Class Branchiopoda 800 species Small: up to 10 cm long Examples: brine shrimp, Water fleas, tadpole shrimp, clam shrimp

Water Fleas

Water Fleas

Brine Shrimp

Class Malacostraca Live in water Pets and food for humans Examples: Includes krill, sow bugs, lobsters, crayfish, shrimp, and crabs

Krill

Lobsters

Crayfish

Crabs

Crustacean diagram

red crabs Christmas island great migrations

Subphylum Myriapoda Class Chilopoda: Centipedes Up to 177 segments 1 pair of legs on each segment Poisonous Examples: centipedes

Subphylum Myriapoda Class Diplopoda 2 pairs of legs on each segment Emit a foul smell instead of poison Example: millipedes

Giant African Millipede

Class Arachnidan 8 legs No wings or antennae Cephalothorax and abdomen Incomplete metamorphosis Squirt digestive juices then suck up their meal Examples: Spiders, mites, ticks and scorpions

Class Arachnida Order Araneae: Spiders Fangs to kill prey and deliver venom Spinnerets to make silk 4 pairs of light sensing eyes 43,000+ species of spiders!!!  bird eating spider

Class Arachnida Order Scorpionida: Scorpions 1300 species Claws for grasping prey Tail with venom gland and stinger Have hair sensory organs Scorpion Scorpions

Class Arachnida Order Acari: Ticks & Mites Most are parasites that feed on blood or hair Cause skin rashes, allergies and spread diseases ticks

Subphylum Myriapoda Class Insecta: Insects 3 pairs of legs 1 million known species Finding new species all the time Show advanced social behavior weird bugs amazing insects honey bees ant communication

Beehive

Queen Bee

Drone Bee

Worker Bee

Worker bee with pollen

Class Insecta: Insects Attracting mates: Emit pheromones Flashes of lights (fireflies) Sounds and color signals luna moth

Class Insecta: Insects Legs are often modified for special purposes Sticky (house fly) Jumping legs (grasshopper and crickets) Paddle-shaped (water bugs, many beetles) Grasping (praying mantis)

Class Insecta Order Odonata Chewing mouthparts Toothed mandibles Winged adults Nymphs and adults differ in appearance Aquatic nymphs w/gills Indicators of good water quality Examples : Dragonflies and Damselflies

Class Insecta Order Orthroptera Chewing mouthparts Straight wings Winged adults Nymph and adults live in same habitat Nymph and adult are similar in appearance Examples: Grasshopper, katydids, and crickets

Class Insecta Order Mantodea Chewing Mandible Winged adults Nymph and adults are similar Examples: Mantids

Class Insecta Order Blattaria Chewing Mandible Winged adults ( not all are winged) Nymph and Adults live in same habitat Nymph and Adults similar in appearance Example: Cockroach

Class Insecta Order Isoptera Chewing mouthparts Equal wings Winged adults Nymphs and adults live in same habitat, and they have similar appearance. Example: Termites

Class Insecta Order Hemiptera Piercing and sucking Usually winged and adults Nymphs and adults live in same habitat Nymphs and adults are similar in appearance Example: Cicada and Aphids

Class Insecta Order Coleoptera Chewing Mouthparts Hardened forewings Winged adults Larvae and adults live in same habitat Larvae and adults aren’t similar in appearance Example: Beetles

Class Insecta Order Siphonoptera Siphoning Wingless adults Larvae and adults aren’t similar in appearance Often pest of mammals Examples: fleas

Class Insecta Order Diptera Sponging, piercing, sucking, bitting Winged Adult 2nd pair of wings are halters Larvae and adults live in same habitat Larvae and adults are not similar in appearance Some spread disease to humans Examples: Flies

Class Insecta Order Lepidoptera Larva: Chewing; Adult: Siphoning Winged Adults Larvae and Adults not similar in appearance Most larvae feed on plant tissue Many moths are pest; most butterflies aren’t Examples: Moths and Butterflies

Class Insecta Order Hymenoptera Chewing & lapping Membrane wings Winged Adults Larvae and Adults not similar in appearance Examples: ants, bees, sawflies, wasps

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