1. Myriapods, Hexapods

2. Subphylum Hexapoda + Subphylum Myriapoda
(primarily) terrestrial mandibulates
Paired mouthparts- chewing/grinding/tearing
Homopteran
Orthopteran
movie

3. Subphylum Hexapoda + Subphylum Myriapoda
Uniramous (unbranched) appendages
Biramous appendage

4. Subphylum Hexapoda + Subphylum Myriapoda
One pair of antennae

5. Subphylum Hexapoda + Subphylum Myriapoda
Use tracheae to carry respiratory gasses
Chitin-lined invaginations of epithelium
Open to the outside via spiracles
Chitin- lined to reduce water loss

6. Subphylum Hexapoda + Subphylum Myriapoda
Excretion by Malpighian tubules
Almost all insects, some myriapods, some spiders
Nitrogenous waste (ammonia) removed by converting into uric acid. Energy costly. In aquatic insects, ammonia simply diffuses out of the body into surrounding water. Excretion of uric acid minimizes water loss. Nearly half of the food energy a terrestrial insect consumes may be used to process metabolic wastes.
Some water, ions, organic compounds are reabsorbed in the basal portion of the Malppighian tubules and the hindgut; the rest are reabsorbed in the rectum. Uric acid moves into the hindgut and is excreted

7. Excretion by Malpighian tubules (cont’d)
Blind-ended tubules bathed in hemolymph
Remove nitrogenous waste (e.g. uric acid), amino acids, sugars
Nitrogenous waste (ammonia) removed by converting into uric acid. Energy costly. In aquatic insects, ammonia simply diffuses out of the body into surrounding water. Excretion of uric acid minimizes water loss. Nearly half of the food energy a terrestrial insect consumes may be used to process metabolic wastes.
Some water, ions, organic compounds are reabsorbed in the basal portion of the Malppighian tubules and the hindgut; the rest are reabsorbed in the rectum. Uric acid moves into the hindgut and is excreted

8. Excretion by Malpighian tubules (cont’d)
Minerals, water resorbed at bottom of tubule and by rectal glands of hindgut
waste passed out
Nitrogenous waste (ammonia) removed by converting into uric acid. Energy costly. In aquatic insects, ammonia simply diffuses out of the body into surrounding water. Excretion of uric acid minimizes water loss. Nearly half of the food energy a terrestrial insect consumes may be used to process metabolic wastes.
Some water, ions, organic compounds are reabsorbed in the basal portion of the Malppighian tubules and the hindgut; the rest are reabsorbed in the rectum. Uric acid moves into the hindgut and is excreted

9. Myriapods

10. Subphylum Myriapoda “many footed” Class Chilopoda Class Diplopoda

11. Class Chilopoda centipedes Serial segmented, flattened body
each segment has a pair of jointed appendages

12. Class Chilopoda (cont’d)
Active predators
kill prey with poison claws and fangs (modified legs on first segment)

13. Class Diplopoda
Millipedes
Serially segmented, rounded body

14. Class Diplopoda 2 smaller pairs of legs per segment
Slow moving; feed on decaying plants movie

15. Subphylum Hexapoda Includes Class Insecta
Beetles, grasshoppers, butterflies, flies, bees…
Movie
movie

16. Class Insecta

17. Most Abundant and Diverse Animal Class
1,000,000+ species identified
May as many as 10,000,000
More than all other animals combined

18. Distribution of Insects
Air
land
In the soil
Parasites
Plants
Animals
Freshwater

19. Reasons for insect success
Small size
Reproductive potential
Co-evolution with plants
Evolution of flight
Metamorphosis

20. Characteristics of Insects
Three body regions
Head
Thorax
Abdomen
Three pair of legs

21. Characteristics (cont)
wings
Absent in some
Pair of compound eyes
Spiracles for respiration

22. External Structure of a Generalized Insect
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
External Structure of a Generalized Insect

23. Internal Structure of a Generalized Insect
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Internal Structure of a Generalized Insect
Fig. 15.8
15-6

24. External structure of insects
Head
one pair of antennae

25. External structure of insects
Head
pair of compound eyes (detect movement)
several sets of simple eyes= ocelli (probably detect changes in light intensity)
Mosquito compound eye

26. External structure of insects (cont’d)
Head
Antennae can be highly variable
Mosquito antennae

27. External structure of insects (cont’d)
Mouthparts are highly modified depending on the type of insect
for piercing and sucking (ie. mosquitos)
movie

28. External structure of insects (cont’d)
Mouthparts are highly modified depending on the type of insect
for chewing (ie. grasshoppers)
movie

29. External structure of insects (cont’d)
Mouthparts are highly modified depending on the type of insect
for siphoning (ie. butterflies)
movie

30. External structure of insects (cont’d)
Mouthparts are highly modified depending on the type of insect
for sponging (ie. flies)
Movie damselfly eating moth

31. External structure of insects (cont’d)
Thorax
consists of three regions:
Prothorax (anterior-most segment)
Mesothorax
Metathorax
One pair of legs attaches along ventral margin of each thoracic region

32. External structure of insects (cont’d)
Insects may have 1 pair, 2 pair, or no wings
Insects are the only invertebrates that can fly movie
Drosophila melanogaster
Archaeognatha (bristletail)

33. Wings of insects= modified exoskeleton
1st pair is often tough and leathery (protection)
fold over the inner pair .

34. Attach to mesothorax and metathorax
Have thickened, hollow veins for increased strength .

35. Abdomen
does not have appendages

36. Abdomen
terminal portions harbor the reproductive structures

37. Insects undergo metamorphosis

38. Metamorphosis Change in form from one developmental stage to another
Yellow bear caterpillar
Change in form from one developmental stage to another
Immature and adult body forms
May not compete
May be incomplete or complete
Monarch butterfly chrysalis
Apollo butterfly

39. Incomplete Metamorphosis
cockroach
Early developmental stages very similar to adults
only the wings and reproductive structures gradually develop

40. Incomplete metamorphosis (cont’d)
cockroach
The immature stages = nymphs
egg---> nymphs ----> adult

41. Complete metamorphosis
Each stage is structurally and functionally very different

42. Complete metamorphosis (cont’d)
The egg develops into an immature larva; eats voraciously
movie

43. Complete metamorphosis (cont’d)
Followed by a transitional stage - pupa, contained within cocoon

44. Complete metamorphosis (cont’d)
Metamorphosis occurs within the pupal exoskeleton, yielding a sexually mature adult
movie

45. Beneficial Insects
Honey bee
Honey
Pollinates crops

46. Beneficial Insects
Silkworm moth
Lava produces silk

47. Beneficial Insects
Breakdown dung

48. Beneficial Insects
Blow fly
Decompose dead bodies

49. Beneficial Insects Lady bug Eats harmful insects
Saved California citrus in ’20s

50. Beneficial Insects Some wasps Kill harmful insects movie Parasitoid
Larvae live in body of host, eventually killing it
movie

51. Fruit Fly
Drosophila
Genetics research

52. Some genes are highly conserved among organisms
NCBI
From Molecular cell biology 5e, Lodish

53. Harmful Insects
Boll weevil
Destroys cotton

54. Harmful Insects
Tent caterpillar
Pest of many trees and shrubs

55. Harmful Insects Mosquitos Vector Malaria Yellow fever Encephalitis
West Nile virus
Movie
Web-linked movie, better

56. Harmful Insects
Flea
Vector for
Plague
Xenopsylla Cheopis

57. Xenopsylla Cheopis
Rat flea
Vector for plague

58. Black Death Bubonic plague 1357-1350 killed 25,000,000 in Europe
1900’s killed 20,000,000 in India

59. Plague Survivor

61. Alexandre Yersin Discovered bacterium Yersinia pestis
Treated with antibiotics