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Insects

Insects. External Anatomy. Adult insects are known for having three major body regions, six legs, one pair of antennae and usually two pair of wings as adults. head. abdomen. thorax. Adult insects develop as a composite of fused segments with specific body part associations.

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Insects

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  1. Insects

  2. External Anatomy Adult insects are known for having three major body regions, six legs, one pair of antennae and usually two pair of wings as adults. head abdomen thorax

  3. Adult insects develop as a composite of fused segments with specific body part associations. from the 1995 Physiology or Medicine Nobel Poster

  4. HEAD antennae compound eyes The first body region is the head. Insect heads can be highly variable, but most possess eyes, antennae and mouthparts. head mouthparts

  5. Antennae beetle butterfly fly ant termite June beetle Antennae are used by insects as major sensory devices, especially for smell, and can be adaptive for the insect in many ways.

  6. Two Examples of Mouthparts chewing piercing/sucking Insect mouthparts are also highly modified for the insect. Chewing, biting, or sucking, are a few examples. Mouthparts of an immature insect may differ from those of the same insect in its adult stage.

  7. Arthropod Vision • Simple eyes • Light sensitive cells share a common lens • Compound eyes • Thousand of closely packed units called ommatidia

  8. Simple ocelli. Complex lensed ocelli. Compound eyes made of ommatidia.

  9. Compound & Simple Eyes

  10. Picture of bodyparts The middle body region is called the thorax and is composed of three fused segments. All legs and wings are located on the thorax. Thorax

  11. swimming digging suction grasping Legs Like the mouthparts and antennae, insect legs are quite variable in form and function and reflect the insect's lifestyle.

  12. Walking Walking involves the coordinated movement of uniramous appendages in different planes.

  13. Centipedes (Class Chilopoda) have one leg per segment on each side. Fast but not as powerful. Walking Subphylum Myriapoda Millipedes (Class Diplopoda) have two legs per segment on each side. Slow but powerful.

  14. Flying Hemipterans (flies) Indirect flight muscles allow wings to beat faster than neural transmission. Dorsoventral and longitudinal muscles. Flexible thorax.

  15. The last body region is called the abdomen. It is composed of many segments connected by flexible sections allowing it great movement. Abdomen

  16. Insects possess an exterior covering called the exoskeleton. They do not have internal bones. This segmented "shell" is what gives insects shape and can be very hard in some insects. It is often covered with a waxy layer and may have "hairs" called setae.

  17. seta ( hair) waxy layer cuticle Exoskeleton x-sec

  18. InternalAnatomy Inside the insect we find the systems for respiration, circulation, nerves, and digestion, but there is little resemblance to the same systems found in man or other mammals.

  19. Digestive System foregut hindgut Digestive sys midgut The digestive system is a tube that opens at the mouth and empties at the tail end of the insect. It is divided into three parts called the foregut, midgut, and hind gut. In some insects such as the honey bee, the foregut acts as a crop to carry or hold liquids which can be regurgitated later.

  20. Circulatory System “ heart ” aortic pumps Circ system The circulatory system is not composed of a central heart, veins and arteries which circulate blood cells and transport oxygen. The insect circulatory system is a simple tube down the back which is open at both ends and slowly pulses body fluids and nutrients from the rear of the insect to the head.

  21. Insects have a less centralized nervous system than humans. The nerve chord runs along the ventral or bottom aspect of an insect. The brain is divided into two main parts. The largest lobes control important areas such as the eyes, antennae, and mouthparts. Other major concentrations of nerve bundles called ganglia occur along the nerve chord and usually control those body functions closest to it. two lobed brain Nervous system (ganglia) nerve bundles Nervous System

  22. The respiratory system is composed of air sacs and tubes called tracheae. Air enters the tubes through a series of openings called spiracles found along the sides of the body. The largest spiracles are usually found on the thorax where greater musculature from wings and legs require more oxygen. There are no spiracles on the head.

  23. tracheal tubes spiracles Respiratory System

  24. Sense organs (sensilla) protrude out of cuticle. Can be slit in cuticle. Membranous drums. Chemoreceptors with thin cuticle. “Brain” is 2-3 ganglia with specific functions. Ganglionated ventral nerve cord.

  25. How do Arthropods reproduce and develop? Most gonochoristic with formal mating and internal fertilization.

  26. metamorphosis metamorphosis LifeCycles The many diverse orders of insects have four different types of life cycles. These life cycles are called "metamorphosis" because of the changes of shape that the insects undergo during development.

  27. Without Metamorphosis egg nymphs adult Without meta The first type is "without" metamorphosis which the wingless primitive orders such as silverfish (Thysanura) and springtails (Collembola) possess. The young resemble adults except for size.

  28. Incomplete Metamorphosis egg naiads adult Incomplete meta The second type is "incomplete" metamorphosis which is found among the aquatic insect orders such as mayflies (Ephemeroptera) and dragonflies (Odonata).

  29. Gradual Metamorphosis The third type is "gradual" metamorphosis seen in such orders as the grasshoppers (Orthoptera), termites (Isoptera), thrips (Thysanoptera), and true bugs (Hemiptera). This life cycle starts as an egg, but each growth, or nymphal stage looks similar, except it lacks wings and the reproductive capacity that the adult possesses. nymphs adult egg

  30. Complete Metamorphosis The fourth type is "complete" metamorphosis found in butterflies (Lepidoptera), beetles (Coleoptera), flies (Diptera), and bees, wasps, and ants (Hymenoptera). This life cycle has the four stages of egg, larva, pupa, and adult. Each stage is quite distinct. egg pupa adult larvae

  31. It should be noted that because insects are hard-bodied, they cannot grow larger gradually. Instead they grow larger in steps by shedding the hard exoskeleton for a brief period of expansion. The brief periods between or within stages are called molts. Insects are soft-bodied and vulnerable during this time. recently molted roach

  32. Molting • Secretion of "molting fluid" to dissolve old endocuticle. • New cuticle formed under old exocuticle. • Break out of old cuticle • Old cuticle breaks at line of weakness

  33. Growth stages • Arthropod passes thru 3-20+ growth stages in life cycle. • Some stop molting as adults (insects, most spiders) • Some continue to molt (crayfish, tarantulas)

  34. Soldier Beetles Order ColeopteraFamily Cantharidae Life History: Adultson flowering shrubsand trees. Larvaein soil.Prey: Aphids, locust eggs, snails, slugs, millipedes, earthworms, caterpillars, and maggots. David Laughlin

  35. Ground Beetles Order ColeopteraFamily Carabidae Life History: Nocturnal, in or on soil, some live up to four years.Prey: Caterpillars, soil and tree insects, earthworms. Top: Harpalus sp.Bottom: Calosoma sp. Vera Krischik

  36. Tiger Beetles Order ColeopteraFamily Cicindellidae Life History:Stalkingpredators,fast runners.Prey: Whateverthey can catch. John Davidson

  37. Rove Beetles Order ColeopteraFamily StaphylinidaeLife History: Nocturnal predators.Prey: Soil-dwelling insects.

  38. Lady Beetles Order ColeopteraFamily CoccinellidaeLife History: Many species, both larvae and adults are predaceous. Prey: Aphids, scale insects, mealybugs, whiteflies, spider mites, insect eggs. Jeff Hahn Pink Lady Beetle(Coleomegilla maculata), a native lady beetle

  39. Convergent Lady Beetle Order ColeopteraFamily CoccinellidaeHippodamia convergensLife History: Native and common in the Midwest; larvae and adults are both predaceous. Prey: Aphids. John Davidson

  40. Multicolored Asian Lady Beetle Order ColeopteraFamily CoccinellidaeHarmonia axyridisLife History: Introduced, invades homes in fall. Prey:Aphidsandscales. John Davidson JohnDavidson John Davidson

  41. Robber Flies Order DipteraFamily AsilidaeLife History: Larvaelive in soil anddecaying wood;adults are fast fliers.Prey: Butterflies, wasps, bees, dragonflies, grasshoppers, beetles, and other flies. Larvae feed on soft-bodied insects such as grasshopper eggs, white grubs, and other insect larvae. Whitney Cranshaw

  42. Gall Midges Order DipteraFamily Cecidomyiidae Life History: Tiny adults feed on honeydew and nectar, larvae are predaceous.Prey: Larvae feed on aphids, mites, scales, whiteflies, and thrips. Whitney Cranshaw Top and bottom: Aphidoletes aphidimyza feeding on aphids

  43. Syrphid or Hover Flies Order DipteraFamily Syrphidae Life History: Adultsfeed on nectar andpollen. Larvae arepredaceous. One generation every 2 to 4 weeks. Prey: Larvae feed on aphids, scales, and other insects. David Laughlin

  44. Tachinid Flies Order DipteraFamily Tachinidae Life History: Adultslay eggs on plants orhosts. Larvae developinside hosts and pupate in 4 to 14 days. One or more generations per year. Prey: Caterpillars, adult and larval beetles, sawfly larvae, true bugs, grasshoppers, and others. John Davidson

  45. Minute Pirate Bugs Order HemipteraFamily AnthocoridaeLife History: Onegeneration takes20 days to complete,multiple generationsper year. Prey: Spider mites, insect eggs, aphids, thrips, scales, caterpillars. Orius insidiosus adult

  46. Seed and Big-Eyed Bugs Order HemipteraFamily Lygaeidae Life History: Many Lygaeids feed on plants, but some are predaceous.Prey: Insect eggs, aphids, mealybugs, spider mites, leafhoppers, plant bugs, whiteflies, caterpillars, and beetle larvae. John Davidson Top and bottom: Geocoris species

  47. Pirate Bugs Order HemipteraFamily Miridae Life History: Most mirids feed on plants, but some are predaceous. Prey: Mites and plant-feeding insects; lace bugs, cotton aphid, tobacco budworm. John Davidson David Laughlin Top: Deraeocoris nebulosus adultBottom: Pirate bug adult (L) and nymph (R)

  48. Stink Bugs Order HemipteraFamily Pentatomidae Life History: Most feedon plants, but someare predaceous. Manydischarge a distastefulsmell when handled.Prey: Caterpillars and beetles such as Colorado potato beetle and Mexican bean beetle. Whitney Cranshaw Predatory stink bug feeding on elm leaf beetle larva

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