I. Phylum Arthropoda: Part IIIII. Insect FlightWings are an outgrowth of the exoskeleton (body wall).Most have two pairs of wings.Class Insecta: Feeding and DigestionDiet is determined by mouth part morphology.Biting or chewing mouthparts.Reproduction & DevelopmentSensory SystemsIV. Stinging InsectsClass Insecta: Human-Insect ConflictBIO SCI 100 1st Edition Lecture 12Outline of Last Lecture I. Phylum ArthropodaII. Class MalacostracaIII. Class ArachnidaIV. Class MerostomataOutline of Current Lecture I. Phylum Arthropoda: Part IIII. Subphylum HexapodaIII. Insect FlightsIV. Stinging InsectsCurrent LectureI. Phylum Arthropoda: Part II- Subphylum Hexapoda.o Class Insecta: Insects.- Subphylum Myripodao Class Chilopoda: centipedes.o Class Diplopoda: millipedes.II. Subphylum HexapodaThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.Class Insecta:- Very diverse in form and function.- Adaptable: all habitats.- Adapt to environmental changes, such as insecticides.- All have 3 Tagmata: o Heado Thoraxo Abdomen- Havetwopairs of wings (usually) andcompoundeyes.- Why are Insects so Adaptable?o The exoskeleton; Allows them to exist in a wide range of habitats. Prevents dehydration.o Modification of limbs for specific purposes: Grabbing food (praying mantis). Digging (mole cricket). Jumping (grasshopper). Wings: ability to disperse long distances.III. Insect Flight- Wings are an outgrowth of the exoskeleton (body wall).o Most have two pairs of wings.o Wings move in a figure 8pattern that allows insects to hover.o Flight controlled by muscles in Thorax.- Indirect flight muscles:o Involved in achieving lift.o Contraction = upstroke.- Direct flight muscles:o Controls direction of flight.o Contraction = down stroke.Class Insecta: Feeding and Digestion- Diet is determined by mouth part morphology.o Biting or chewing mouthparts.o Common in herbivorous and predatory insects. Mandibles with cutting plates; chew food. Maxillae hold & manipulate food and pass it to mouth.o Sucking mouthparts House flies: No mandibles, lobes that sponge up liquid. Mosquitoes: No mandibles, piercing &sucking mouthparts. Butterflies: No mandibles, Maxillae modified into long sucking tube to extract nectar (like a straw).Reproduction & Development - Dioecious with internal fertilization.- Females lay many eggs via an ovipositor.o (E.g., queen bee lays greater than 1 million eggs in her lifetime).- Eggs often laid in specifichabitat (i.e. on a specific plant).- Two types of development:o Most species (88% of insects) have complete metamorphosis.o Each stage: Can occur in different habitats. Eat different foods. Has different function:- Larva = growth.- Pupa = differentiation.- Adult = reproduction.o This reduces competition.- Other species (12 %) have gradual metamorphosis.o Young are called nymphs or instars.o Resemble adults without wings.o Grow by successive molts.Sensory Systems- Nervous system: brain, and longitudinal nerve cords that branch.- Antennae for chemical reception.- Compound eyes.Class Insecta: Communication- Chemical signals: Pheromones.o Trail markers, territorial markers, attraction of reproductive partners and indicates caste in social insects.- Sound production: warning calls, courtship songs and advertise territorial boundaries.- Tactile signals: touching antennae to identify individuals or pass on warning signal.- Visual signals: Colors to warn predators of toxicity like aposomatic coloration (milkweed bug).o Also, bioluminescence to attract mates (firefly).Class Insecta: Social Behavior- Many insects form societies.o A colony or community of cooperating individuals.o Often includes a caste system (e.g. bees). Queen (sole reproductive female). Drones (few hundred sexually mature males). Workers (thousands of sexually inactive females): tend to young and gather food.o Some colonies have evolved group behaviors: Leaf cutter ants harvest leaves; bring them into their burrows to grow special fungus, on which they feed. Act like farmers.Defensive Adaptations & Behavior- Crypsis: Camouflage coloration.- Toxicity: Aposomaticcoloration.IV. Stinging Insects- Bees, Wasps, Hornets: o Stinger for injecting venom.- Africanized bees:o Very aggressive.o Hybrids of African &European bees.o Introduced to South America in 1956.o Spread to the US (South/Southwest) in 1990.Class Insecta: Benefits from Insects- Crop pollination: bees pollinate almost $14 billion in food crops per year.- Insect predators feed on insect pests.o Lady bug& praying mantis.- Detritivores: eat decaying plant & animal material.o Dung beetles.Class Insecta: Human-Insect Conflict- Fleas: carrying black plague.- Locusts: destroy crops.- Tent caterpillars: strip trees of leaves.- Mosquitoes: transmit diseases; Malaria and West Nile Virus.- Ticks: Lyme Disease.- Emerald Ash Borer: kills Ash