4 Insect Orders


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4 Insect Orders

  1. 1. Arthropods Insects and their relatives
  2. 2. Insects and Their Relatives Characteristics – Exoskeleton (external covering) – Molts or sheds exoskeleton to grow – Undergo metamorphosis or pass through a number of distinct growth stages during their lives
  3. 3. Metamorphosis Simple or gradual – three changes • egg • nymph – 3-5 instars • adult – adults and nymphs • eat same food
  4. 4. Metamorphosis Complex or complete – four changes • egg • larva • pupa • adult – larvae and adults • eat different food – larvae are destructive
  5. 5. External structure Insects – 3 body regions • head • thorax • abdomen – 3 pair legs attached to thorax – 1 pair antennae – wings usually present in adult state.
  6. 6. External structure Arachnids (spiders and mites) – 2 body regions • cephalothorax • abdomen – usually 4 pair legs – no wings – no antennae
  7. 7. Other Arthropods Crustaceans Mollusca – Pillbugs – snails – Sowbugs – slugs Pillbugs - photo J. Kalish - UNL Gray garden slug photo Ohio State University
  8. 8. Other Arthropods Diplopoda Chilopoda – Millipedes – Centipedes Photo J. Kalish - UNL
  9. 9. Insect Orders
  10. 10. Beetles - Coleoptera Largest order of insects (25,000 species in North America) Many species are plant feeders, some are predaceous (lady beetles) The term weevil refers to a snouted beetle
  11. 11. Beetles Metamorphosis – Complete or complex Mouth parts – Chewing (both adult and larvae)
  12. 12. Beetles - Adults • Wing: 2 pair, the front pair (elytra) are greatly thickened and shell-like and when at rest meet in a straight line down the back. Hind membranous wing pair is protected by front pair.
  13. 13. Beetles - Larvae Larvae that feed externally on plants are typical “grub” with head capsule, 3 pair of legs on the thorax, and no legs on the abdomen
  14. 14. Beetles - Larvae Larva that feed internally in plants (e.g. bark beetles, weevils, woodborers) typically lack legs. Chewing mouthparts
  15. 15. Earwigs- Dermaptera Introduced from Europe Metamorphosis: gradual or simple Mouthparts: chewing, general feeders on decaying organic matter, occasionally feed on plants and insects. Can pinch with mouthparts.
  16. 16. Earwigs Wings: 2 pair; front wings are short leathery without venation and meet in a straight line down the back when at rest. Can be confused with those of beetles, but beetles do not have forceps-like cerci.
  17. 17. Earwigs Body: Elongated, flattened Cerci: Tail-like pinchers. The cerci on males are bowed, while straight on females. Cerci cannot produce a painful pinch. Habit: Over winters as adults. During the day, earwigs like to hide in dark, moist areas.
  18. 18. Flies, Gnats, Midges, Mosquitoes- Diptera Second only to beetles in number. Feeding habits vary widely – Scavengers (house flies, blow flies) – Blood feeding (mosquitoes) – Plant galls (gall midges) – Predators (flower flies, robber flies) – Aquatic
  19. 19. Flies, Gnats, Midges, Mosquitoes If the fly is a Diptera, the name is written as two words (house fly, deer fly). If the fly is not a Diptera, the name is written as one word (sawfly, butterfly, whitefly)
  20. 20. Flies, Gnats, Midges Metamorphosis : Complete
  21. 21. Flies, Gnats, Midges -Adult Wings: 1 pair of wings (an easy ID for Diptera). Adults are typically soft bodied and often hairy. – Note: They may look like bees, wasps or flies---count the wings! On many Hymenoptera the wings may be attached and the hind wings may be hidden under the front wing.
  22. 22. Flies, Gnats, Midges- Adult Mouthparts: highly variable – Sponging (house fly) – Cutting-lapping (horse fly) – Piercing-sucking (mosquito)
  23. 23. Flies, Gnats, Midges - larvae Vary greatly in Lower forms, such appearance. Larva as mosquitoes, have of advanced forms, a small head like the house fly, capsule. are maggot type having mouth hooks and not head capsule or legs.
  24. 24. Hemiptera True bugs: plant bugs, squash bugs, stink bugs Order includes many important predators. If the bug is a Hemiptera the name is written as two words (stink bug, water bug, squash bug). If the insect is not a Hemiptera, the name is written as one word (ladybug)
  25. 25. True Bugs Metamorphosis: gradual or simple Mouthparts: piercing-sucking. Mouthparts usually easily visible and appears to arise from front of head, ahead of eyes. By contrast Homoptera mouthparts are not very visible and appear to arise from the area between the front pair of legs.
  26. 26. True Bugs Wings: 2 pair. Front wings (called hemielytra) are thickened at base and membranous at end, and overlap at tips when at rest. Hind wings are membranous. Nymphs have no wings, but wing pads may be visible in older nymphs.
  27. 27. True Bugs Body: Usually broad and somewhat flattened; a triangular plate (the scutellum) is located between the base of the wings.
  28. 28. Homoptera Aphids, cicadas, leafhoppers, mealybugs psyllids, scales, whitefiles All species are plant Insects in this order feeders, often are carriers feeding on phloem (vectors) of several sap. plant pathogens. Excretion of honey dew is common to honeydew many members of the order.
  29. 29. Aphids and Psyllids, etc Metamorphosis: gradual; nymphs and adults similar in appearance (except scales and whiteflies)
  30. 30. Aphids and Psyllids, etc Mouthparts: Piercing-sucking; jointed beak-like mouthparts. Not very visible and appear to arise from the area between the front pair of legs. By contrast, Hemiptera mouthparts are usually easily visible and appear to arise from the front of the head, ahead of the eyes.
  31. 31. Aphids and Psyllids, etc Wings: 2 pair of membranous wings; generally held roof- like over the body when at rest. Many wingless forms occur. No wings on nymphs, but wing pads may be observed on older nymphs.
  32. 32. Hymenoptera Ants, bees, horntails, sawflies, wasps Order includes many important parasites and predators. The order has the most highly developed insect behaviors and social patterns.
  33. 33. Bees, Wasps, Sawflies Metamorphosis: complete Mouthparts: chewing or chewing- sucking
  34. 34. Bees, Wasps, Sawflies - Adult Wings: 2 pair membranous wings, often hooked together. Hind pair are usually smaller. Mouthparts: typically chewing or chewing-sucking
  35. 35. Bees, Wasps, Sawflies - Adult Body: Adults are rather soft-bodied or slightly hardened bodies. Most species have a distinct constriction between the thorax and abdomen (wasp waist). Exception: sawfly/horntail group does not have the wasp waist. Antennae: jointed sometimes elbowed. Stinger: female abdomen usually provided with a saw, piercing organ, or stinger.
  36. 36. Bees, Wasps, Sawflies - Larvae Larva of most species are rarely observed, often developing in a nest or as an internal parasite. Head: a distinct head capsule Mouthparts: chewing
  37. 37. Bees, Wasps, Sawflies - Larvae Legs: none (except some sawfly larva) – Note: Sawfly larva may look like caterpillars. Caterpillars have up to 5 pair of prolegs on abdomen. Sawfly larvae have 6+ pair prolegs on abdomen.
  38. 38. Lepidoptera Butterflies, moths, skippers Metamorphosis: complete Mouthparts: coiled sucking tube (lapping) as adults. Some adults don’t feed at all. As larvae have chewing mouthparts Egg Mass Cocoon Caterpillar Butterfly
  39. 39. Butterflies, Moths, Skippers - Adult Wings: 2 pair often large, covered with small overlapping scales, often but not always brightly colored. Black Swallowtail Black swallowtail larva
  40. 40. Butterflies and Moths- Adults Butterflies have slender bodies, the wings are held vertical when at rest, and the antennae are slender and club like at the tips. They are day fliers. Moths have stout bodies and wings are held in a roof like horizontal position over the body when at rest. Antennae are variable in form, but usually filamentous of featherlike. Most fly at night
  41. 41. Skippers - Adults Skippers dart or skip through the air in flight during the day. Their bodies are intermediate in form, between the moths and common butterflies. Their wings are held erect when at rest. The antennae of skippers are club-like at the tips, and often have hook-like ends of the club or knob.
  42. 42. Lepidoptera larvae: Caterpillars Legs: 3 pair of legs on thorax Prolegs: Up to 5 pair of prolegs (fleshy leg-like structure with hook-like crochets on the end) on some abdominal segments.) – Note: Sawfly larvae look like smooth bodied caterpillars but have more than 5 pair of prolegs on the abdomen. Their bodies also taper from the head.
  43. 43. Caterpillars Decorations: Often highly colored or decorated with spines or other appendages. Mouthparts: Chewing mouthparts with voracious appetites. Variegated Fritillary Larva Variegated Fritillary Adult
  44. 44. Thysanoptera Thrips Very common insects, but due to the tiny size are rarely observed. Feeding leaves the plant looking scarred, as they rasp the leaf or flower surface and suck plant fluids. Thrips
  45. 45. Thrips Metamorphosis: a variation of gradual Mouthparts: rasping-sucking Wings: 4 (2 pair) slender wings fringed with hairs, often absent. Tarsi: Feet are 1 or 2 segmented, each with a balloon-like structure on the end. Size: minute, less than 1/8 inch long.
  46. 46. Orthoptera Crickets, grasshoppers, katydids Most are plant feeders. A few are predators. Note: Some books place Mantodea (mantids), Phasmida (walking sticks) and Blattaria (roaches) in the order Orthoptera.
  47. 47. Grasshoppers and Crickets Metamorphosis Gradual Mouthparts: chewing Wings: Usually have 2 pair of wings. Front wings more or less parchment-like with distinct venations. Wings may overlap at rest. Wings may be used to make sounds.
  48. 48. Grasshoppers and Crickets Legs: Hind legs designed for jumping. Antennae: thread-like. Cerci: 1 pair tail-like appendages on most adults.
  49. 49. Insect relatives - Mites Two body segments 8 legs. Tiny soft- bodied organisms that appear almost everywhere. Adult and immatures have sucking mouthparts Two types Spider mites – spider mites – eriophyid mites
  50. 50. Mites Foliage, buds, stems, and fruit of infested plants may become red, bronze, yellow, white or brown. Spider mites spin webs. Stippling or mottling symptom of spider mite feeding.