Crustacean lecture

1. ARTHROPODS AND ECHINODERMS ABCS 101 Department of Animal Biology and ConservaBon Science November 9, 2012 ABCS 101 (Introductory Animal Biology) 1

2. Purpose This aspect of the course is to assist students to recognize the basic structure and funcEon of arthropods and echinoderms as well as their basic ecology; the applicaEon of this knowledge should aid in the management of biodiversity towards improving the student’s quality of life and that of the larger community. November 9, 2012 ABCS 101 (Introductory Animal Biology) 2

3. ObjecBves •  IdenEfy features and characters for classiﬁcaEon into groups (taxonomic nomenclature) •  Describe the biology of arthropods and echinoderms in their varied environments •  Demonstrate the importance of arthropods and echinoderms to life •  Apply knowledge gained of arthropods and echinoderms to help develop biodiversity conservaEon strategies November 9, 2012 ABCS 101 (Introductory Animal Biology) 3

4. Principal learning outcome By the end of this part of the course, students should be able to use the knowledge acquired to correctly idenEfy some common groups of arthropods and echinoderms, describe how they are generally adapted to their environments and aid in management and maintenance of biodiversity eﬀorts November 9, 2012 ABCS 101 (Introductory Animal Biology) 4

5. Procedure •  •  •  •  •  •  •  Lectures Group discussions Audio visual aids Assignments PracEcals Interim assessments ExaminaEons November 9, 2012 ABCS 101 (Introductory Animal Biology) 5

6. Scope WEEK 1 Arthropoda: Chelicerata, Merostomata, Arachnida and Mandibulata, WEEK 2 Arthopoda: Diplopoda, Chilopoda, Crustacea and Hexapoda (Insecta) WEEK 3 Echinodermata: Echiroidea, Asteroidea, Ophiuroidea, Crinoidea, Holothuroidea, the water vascular system WEEK 4 AMMENDMENTS? Reading Materials: •  Life The Science of Biology: Purves, Sadava, Orians and Heller (2008). 8th Ed. Sinauer Associates, Inc./ W.H. Freema and Company •  Zoology: Miller and Harley (1996). 3rd Ed. WCB/McGraw Hill. November 9, 2012 ABCS 101 (Introductory Animal Biology) 6

7. ARTHROPODS November 9, 2012 ABCS 101 (Introductory Animal Biology) 7

8. ObjecBves •  Describe the general morphology of arthropods •  IdenEfy and classify arthropods into groups based on unique characterisEcs •  Describe the distribuEon and coping mechanisms to problems of life November 9, 2012 ABCS 101 (Introductory Animal Biology) 8

9. ARTHROPODS November 9, 2012 ABCS 101 (Introductory Animal Biology) 9

10. ARTHROPODS •  What account for their success? –  Metamerism and TagmaEzaEon –  Exoskeleton –  Metamorphosis November 9, 2012 ABCS 101 (Introductory Animal Biology) 10

11. ARTHROPOD CHARACTERISTICS •  Main features: – segmented body (metamerism), -‐jointed appendages, -‐ hard external skeleton (ChiEnous exoskeleton). – Body segmentaEon and tagmaEzaEon •  Three disEnct body segments – Head, Thorax and Abdomen. •  Head may fuse with thorax: Cephalothorax November 9, 2012 ABCS 101 (Introductory Animal Biology) 11

12. ARTHROPOD CHARACTERISTICS • Jointed appendages: -‐Structures extending from body wall • Bending joints [“Arthro” “poda” means “joint” “footed”] • Movement • Exoskeleton: -‐Rigid outer layer composed primarily of chiEn. • ProtecEon against predators and water loss • Structural support and muscle ajachment for movement • Adult grow by ecdysis; periodic shedding of exoskeleton for a new larger one (molEng). November 9, 2012 ABCS 101 (Introductory Animal Biology) 12

13. ARTHROPOD CHARACTERISTICS ChiBnous exoskeleton November 9, 2012 ABCS 101 (Introductory Animal Biology) 13

14. ARTHROPOD CHARACTERISTICS RespiraBon and circulaBon • Majority breathe through network of ﬁne tubes: trachea • Others breathe through book lungs. • Most aquaEc arthropods breathe through gills. • Open circulatory system: blood is not always contained within vessels. November 9, 2012 ABCS 101 (Introductory Animal Biology) 14

15. ARTHROPOD CHARACTERISTICS Feeding, digesBon and excreBon •  Varied mouthparts and appendages for obtaining food •  IntesEnal tract extends from mouth to anus –  contains structures specialized for: storage, mechanical and chemical digesEon, nutrient absorpEon, and eliminaEon of digesEve wastes •  Excretory system composed of Malpighian tubules. November 9, 2012 ABCS 101 (Introductory Animal Biology) 15

16. ARTHROPOD CHARACTERISTICS Feeding, digesBon and excreBon •  Varied mouth part types –  BiEng and chewing –  Piecing and sucking –  Sucking –  Tearing and sucking November 9, 2012 ABCS 101 (Introductory Animal Biology) 16

17. ARTHROPOD CHARACTERISTICS Vision: Compound eyes • Predominantly compound eyes, composed of thousands of individual visual units. • Units send signals to brain which then composes image of object. • Compound eye exceptionally good for movement detection – Hence difficult to sneak up on flies November 9, 2012 ABCS 101 (Introductory Animal Biology) 17

18. ARTHROPOD CHARACTERISTICS ReproducBon •  Reproduce via sexual reproducEon –  Internal ferElizaEon in most species, but external in some •  Most species are dioecious (i.e. have separate sexes) •  Sedentary/parasiEc arthropods species are olen hermaphodites –  Free-‐living species may exhibit various degrees of sexual reproducEon. –  Parthenogenesis commonly occurs in Insects, Branchiopods and some freshwater copepods November 9, 2012 ABCS 101 (Introductory Animal Biology) 18

19. ARTHROPOD LIFE CYCLE •  Arthropods mostly reproduce only sexually, – parthenogenesis may occur •  Eggs laid outside female’s body •  No parental care received. ExcepEon are scorpions Metamorphosis –  Complete metamorphosis –  Incomplete metamorphosis November 9, 2012 ABCS 101 (Introductory Animal Biology) 19

20. ARTHROPOD LIFE CYCLE MolBng •  Exoskeleton for protecEon but does not grow, periodic shedding of exoskeleton required and grow a new one. •  The process of shedding and discarding exoskeleton termed; mol6ng via ecdysis •  Allows arthropods to grow a larger body •  Most arthropods molt several Emes before adulthood November 9, 2012 ABCS 101 (Introductory Animal Biology) 20

21. ARTHROPOD DIVERSITY •  Total number of arthropods exceeds number of all other animal species combined •  Due to their enormous evoluEonary success •  Exoskeleton provides adaptaEon to life on land/ water; small sized, and show a wide range of specializaEon in food sources and habitats. November 9, 2012 ABCS 101 (Introductory Animal Biology) 21

22. ARTHROPOD DIVERSITY There are 4 main Arthropods groups (Subphyllum): •  Uniramia (Hexapoda (insects), Myriapoda (millipedes and cenEpedes)) •  Crustacea (lobsters and shrimps), •  Chelicerata (spiders, scorpions, mites, Ecks, and horseshoe crabs) •  Trilobita (exEnct lived during the Cambrian period -‐ 600 million yrs ago.) November 9, 2012 ABCS 101 (Introductory Animal Biology) 22

23. ARTHROPOD DIVERSITY • Living arthropods are tradiEonally divided into two groups— arthropods that have jaws and arthropods that have fangs or pincers. •  Members of the subphylum Chelicerata have fangs or pincers. •  Members of the other subphyla have jaws-‐ Mandibulata (Mandibulata is a group of arthropods characterized by mandibles (mouthparts) used for biEng, cupng, and holding food) November 9, 2012 ABCS 101 (Introductory Animal Biology) 23

24. PHYLLUM ARTHROPODA •  •  •  •  Diplopoda Myriapoda Chilopoda Insecta (Hexapoda) Crustacea November 9, 2012 MANDIBULATA ABCS 101 (Introductory Animal Biology) 24

25. PHYLUM ARTHROPODA  Subphylum Uniramia Class Chilopoda Class Diplopoda Class Insecta/Hexapoda (Unbranched (uniramous) appendages with a single pair of antennae)   Subphylum Crustacea Class Malacostraca Class Remipedia Class Copepoda Class Cirripedia Class Cephalocarida Class Branchiopoda (Biramous appendages: branched appendage with 2 pairs of antennae) November 9, 2012 ABCS 101 (Introductory Animal Biology) 25

26. CHILOPODA AND DIPLOPODA (CENTIPEDES AND MILLIPEDES) Myriapods • The name Myriapoda mean “many footed.” • Each myriapod has a head region that is followed by many similar segments • CenEpedes have one pair of legs per segment and millipedes usually have two pair of legs per segment November 9, 2012 ABCS 101 (Introductory Animal Biology) 26

27. CLASS CHILOPODA •  Class of terrestrial Myriapods comprising approximately 3000 species •  distributed over all conEnents, from sea level to high alEtudes •  Some species are however marine •  CenEpedes are nocturnal predators that live under stones, under the bark of tree trunks, in moss, in leaf lijer, soil, under logs, in caves and occassionally in people’s home. November 9, 2012 ABCS 101 (Introductory Animal Biology) 27

28. CLASS CHILOPODA • Legs are long, enabling them to run rapidly •  Predominantly sol-‐bodied myriapods, measuring 1-‐10 cm long, bear 15-‐191 pairs of legs (Minelli 1993) •  Posses a head and elongated trunk with many segments, each bearing a legs • Body is covered by unwaxed cuEcle November 9, 2012 ABCS 101 (Introductory Animal Biology) 28

29. Class Chilopoda •  Head bears a single pair of antennae a pair of mandibles for chewing a pair of ﬁrst and second maxillae a pair of maxillipeds (modiﬁed for subduing prey) contain poison glands and resemble fangs •  Presence of large brain connected with a ventral chain of ganglia •  lacks eyes (when present, are generally simple light receptors called ocelli ) Compound eyes occur in one family, and simple eyes or none at all in many The feelers, certain bristles, and porEons of the skin are also sensory. November 9, 2012 ABCS 101 (Introductory Animal Biology) 29

30. Class Chilopoda  Head is followed by 15 or more leg-‐ bearing segements. Some species have repugnatorial glands on the ventral surface of each segement or on some of the legs themselves (these gland discourage predaEon by producing an adhesive ejaculate)  A number of sp. produce silk from silk glands. Most species are long-‐legged runners, some have legs adapted for burrowing through the soil (in these sp. , legs are reduced and thrust is generated by exploiEng the properEes of hydrostaEc skeleton – earthworm like) November 9, 2012 ABCS 101 (Introductory Animal Biology) 30

31. November 9, 2012 ABCS 101 (Introductory Animal Biology) 31

34. Class Chilopoda Feeding •  They are carnivorous and feed upon other animals mostly insects some larger ones cenEpedes have been known to feed on snakes mice and frogs •  Aler using their jaws to capture their prey, they inject a venom into the animal to kill it. •  Prey is captured and killed with poison claws located just behind the head on the ﬁrst trunk segment. •  Pair of poison glands at the base of the claws empty into ducts that open at the Ep of the pointed fanglike claw. The alimentary canal is straight, food is digested and absorbed November 9, 2012 ABCS 101 (Introductory Animal Biology) 34

35. Class Chilopoda CirculaEon and Gaseous exchange   The heart is a chambered dorsal vessel  RespiraEon is accomplished by trachea, but spiracles cannot be closed. (thus most are restricted to moist environments due to diﬃculty in restricEng water loss)  Tracheae, or air tubes, open on the sides of the body and are connected to one another on each side Many thus conserve water by nocturnal-‐ that is by avoiding the heat of the day and becoming acEve only at night. November 9, 2012 ABCS 101 (Introductory Animal Biology) 35

36. CLASS CHILOPODA REPRODUCTION and GROWTH • One genus bears live young; the others lay eggs • FerElizaEon is internal • ReproducEon may involve courtship display, where the male lays down silk web. • A spermatophore is placed in the web and picked up by females them introduces it her genital opening • Eggs are ferElized as they are laid. November 9, 2012 ABCS 101 (Introductory Animal Biology) 36

37. CLASS CHILOPODA REPRODUCTION and GROWTH •  Some cenEpedes can live as long as ﬁve or six years. • They lay their eggs in the soil during warmer seasons. • While some species of cenEpedes can add segments and legs as they mature, others are born with their complete set of body segments and legs. • Most cenEpedes measure about 2.5 to 5 cm (about 1 to 2 in) in length, but some tropical species grow to about 30 cm (about 12 in) through molEng November 9, 2012 ABCS 101 (Introductory Animal Biology) 37

38. CLASS CHILOPODA ExcreEon The major excretory structure in the chilopoda are the Malpighian tubules Some uric acid is produced, but major waste product of the cenEpede is amonnia November 9, 2012 ABCS 101 (Introductory Animal Biology) 38

39. CLASS CHILOPODA DIVERSITY • A total of ﬁve orders of cenEpedes are currently recognized within the extant Chilopoda: • ScuEgeromorpha • Lithobiomorpha • CraterosEgmomorpha • Scolo-‐ pendromorpha • Geophilomorpha. • One exEnct order, Devonobiomorpha, is also accepted November 9, 2012 ABCS 101 (Introductory Animal Biology) 39

40. CLASS CHILOPODA DIVERSITY ScuEgeromorpha (i.e. the synanthropic cosmopolitan house cenEpede ScuEgera coleoptrata), have pseudo faceted eyes resembling the compound eyes of insects, 15 pairs of very elongated legs, and dorsal respiratory openings There are also 15 pairs of legs in Lithobiomorpha and CraterosEgmomorpha, a poorly known group comprising two species from New Zealand and Tasmania. The Geophilomorpha comprises 11 families of worm-‐like bodied cenEpedes, bearing 29-‐191 pairs of short legs. The largest cenEpedes (reaching 25 cm long) belong to the Scolopendromorpha, and bear 21-‐23 pairs of legs. November 9, 2012 ABCS 101 (Introductory Animal Biology) 40

42.   The bite of some Scolopendromorpha can inflict serious injury to humans.   ScuEgeromorpha and Lithobiomorpha have a type of development known as anamorphic, in which segment number increases during postembryonic life (Anamorpha).   Contrast, Scolopendromorpha and Geophilomorpha have an epimorphic development, in which the definiEve number of body segments appears upon hatching (Epimorpha).   The condiEon of Cratero-‐sEgmomorpha is unclear because they are not strictly anamorphic, as they achieve the final number of legs aler only one molt, and have been suggested to be the sister group of the Epimorpha November 9, 2012 ABCS 101 (Introductory Animal Biology) 42

43. CLASS CHILOPODA •  Some species of cenEpedes are considered venomous to humans, but their bite is not sufficiently toxic to be lethal to children or adults. • A bite from any of the smaller species usually produces a moderate reacEon that, at worst, is similar to a bee sEng. • The bite of the larger species may produce local inflammaEon, redness, and swelling – and occasionally systemic symptoms that disappear in four to five hours. •  Contrary to myth, a cenEpede walking on your skin will not kill the Essue or cause the skin to rot. •  • They do, however, have relaEvely sharp claws on their legs that can scratch. November 9, 2012 ABCS 101 (Introductory Animal Biology) 43

45. CLASS DIPLOPODA November 9, 2012 ABCS 101 (Introductory Animal Biology) 45

46. Class Diplopoda •  Known as millipedes (thousand-‐ legged) They are commonly called “thousand leggers,” even though they may only have 60 to 400 legs. •  Abt 12,000 known species, abt 4X the number of known cenEpede sp. •  Primarily slow moving deposit feeders that plow through the soil and decaying organic materials (herbivorous) •  Some carnivorous sp. occur •  Pairs of segments have become fused ( diplosegements – double trunk segments-‐ resulEng from the fusion of 2 origInal segment) •  Each double segment has two pairs of legs and contain 2 pairs of spiracles and ventral ganglia •  The most anterior 3 or 4 segments have only a single pair of legs •  The body of a millipede is cylindrical •  In many sp. the integument (body covering) is impregnated with calcium salts (as in crustaceans) making their covering more protecEve against abrasion and predaEon than that of the cenEpede November 9, 2012 ABCS 101 (Introductory Animal Biology) 46

47. Class Diplopoda  As in the cenEpedes, however, the cuEcle is not waxy  Many sp. lack eyes, but as many as 80 ocelli are found on the head of some species   Compound eyes are absent  Head appendages consist of pair of mandibles and a pair of maxillae (DisEnct second maxillae are lacking among millipedes) Instead ﬁrst and second maxillae on each side are fused to form a single appendage November 9, 2012 ABCS 101 (Introductory Animal Biology) 47

48. Class Diplopoda •  Millipedes consEtute a major component of the soil-‐ lijer macrofauna •  Some species (e.g. Dendrostreptus macracanthus, Cleidogona scandens) occur in the forest canopy and have been found in epiphytes such as bromeliads •  In tropical rain forest environments, some species can be found as deep as 20 cm in the soil •  Millipedes are olen collected in ropng logs and under stones, as well as in ant nests as potenEal commensals •  Even though they may invade houses, they pose no threat. •  They do not bite, sEng, cause structural damage, contaminate foodstuﬀs, or eat ﬁber November 9, 2012 ABCS 101 (Introductory Animal Biology) 48

49. Class Diplopoda LocomoBon and protecBon •  Because of their numerous legs, the animals walk slowly, with a wavelike moEon of the legs down the body. Their legs move simultaneously pushing against the substrate, thus enabling them move freely in their habitat. •  In length they range from about 0.2 to 23 cm (about 0.1 to 9 in) •  In most species there is the sEnk glands with secreEons that repel or kill insect predators. •  Most sp have an abundance of repugnatorial glands which eject a variety of toxic, repellent secreEons (hydrogen cyanide – precursor compound + enzyme ) •  Another protecEve strategy is to curl into a spiral or a ball when threatened •  Millipedes are also ajracted to lights, and it is common to have them migrate to lighted areas. November 9, 2012 ABCS 101 (Introductory Animal Biology) 49

50. Class Diplopoda Feeding •  They are herbivorous •  The principal mouth structures are the mandibles modiﬁed for scraping and chewing •  A few sp. have modiﬁed mouth parts for sucking plant juice •  The animals live in dark, damp places and feed on decaying plant life, someEmes damaging crops but also enriching the soil •  Most millipedes feed on damp and decaying vegetaEon and leaf lijer, although some species will ajack the roots and lower leaves of living plants. •  They spend most of their life in the soil. •  Adult millipedes spend cooler days in soil, debris, and leaf lijer found under trees. November 9, 2012 ABCS 101 (Introductory Animal Biology) 50

51. Class Diplopoda DigesEon •  A peritrophic membrane lines the midgut of millipedes, presumably to protect against abrasion •  Food becomesenclosed by this membrane as it moves through the gut, and new peri-‐ trophic membrane is secreted. •  Gut is esenEally a linear tube. November 9, 2012 ABCS 101 (Introductory Animal Biology) 51

52. Class Diplopoda ReproducBon and Growth •  Sexual •  Usually have a complex male copulatory devices that are modiﬁed appendages. •  In some subclass (Pentazonia), the last two or three pairs of legs at the posterior body end are transformed into telopods, which are used by the males during copula to clasp the female vulva. •  In millipede males of the subclass Helminthomorpha, the copulatory organs are situated at the 7th and 8th body rings, replacing one or two pairs of walking appendages November 9, 2012 ABCS 101 (Introductory Animal Biology) 52

53. Class Diplopoda ReproducBon and Growth •  Sexual reproducEon •  Sperms are transferred to the female with modiﬁed trunk appendages of the male, called gonods, or spermatophores. •  Eggs are ferElized as they are laid •  Female millipedes lay their eggs usually during the moist seasons. •  It has been reported that a female millipede can produce as many as 300 eggs at one Eme. •  These eggs are laid in the soil in several small clusters of 20 to 100 eggs. November 9, 2012 ABCS 101 (Introductory Animal Biology) 53

54. Class Diplopoda ReproducBon and Growth •  In about three weeks, the eggs hatch into Eny larvae with only three pairs of legs. •  As millipedes grow, they molt from seven to ten Emes, adding addiEonal body segments and legs with each molt. •  Millipedes stop growing when they reach sexual maturity. •  Adults may live for two to ﬁve years. November 9, 2012 ABCS 101 (Introductory Animal Biology) 54

55. Class Diplopoda •  RespiraBon and CirculaBon  The heart is a chambered dorsal vessel  RespiraEon is accomplished by trachea, but spiracles cannot be closed.(thus most are restricted to moist environments due to diﬃculty in restricEng water loss)  Tracheae, or air tubes, open on the sides of the body and are connected to one another on each side –  Many thus conserve water by nocturnal-‐ that is by avoiding the heat of the day and becoming acEve only at night. November 9, 2012 ABCS 101 (Introductory Animal Biology) 55

56. Class Diplopoda Diversity •  The 144 currently recognized families of millipedes are classified in 15 orders,which are arranged in three subclasses: »  Penicillata, »  Pentazonia, and »  Helminthomorpha. •  The Penicillata,or bristle millipedes, are very small soil dwellers with uncalcified cuEcle. The group contains about 80 nominal species •  The Pentazonia (comprising three orders, Glomeridesmida, Glomerida, and Sphaerotheriida) and •  the Helminthomorpha possess a strongly calcified cuEcle. The vast majority of millipede species belongs to the Helminthomorpha. November 9, 2012 ABCS 101 (Introductory Animal Biology) 56

57. Class Diplopoda and Chilopoda Millipedes diﬀer from cenEpedes in that they have one pair of short antennae on the head and two pairs of legs on each body segment Each myriapod has a head region that is followed by many similar segments. CenBpedes have one pair of legs per segment and millipedes usually have two pair of legs per segment. November 9, 2012 ABCS 101 (Introductory Animal Biology) 57

61. INTRODUCTORY ANIMALS BIOLOGY ARTHROPODA Cont’d INSECTS AND CRUSTACEANS Ms. Juliet Ewool Dept. of Animal Biology & ConservaBon Science (DABCS) November 9, 2012 ABCS 101 (Introductory Animal Biology) 61

62. PHYLUM ARTHROPODA  Subphylum Uniramia Class Chilopoda Class Diplopoda Class Insecta (They possess unbranched (uniramous) appendages and Bear a single pair of antennae)   Subphylum Crustacea Class Malascostraca Class Ostracoda Class Copepoda Class Cirripedia Class Pentastomida (Biramous appendages: branched appendage with 2 pairs of antennae) November 9, 2012 ABCS 101 (Introductory Animal Biology) 62

63. Subphylum Uniramia •  Class Chilopoda •  Class Diplopoda •  Class Insecta November 9, 2012 ABCS 101 (Introductory Animal Biology) 63

64. Subphylum Uniramia Class Insecta •  Over 750,000 described species (most successful group of animals on our planet in terms of diversity and number of species, as well as number of individuals •  Among the best studied of the invertebrates, in a large part due to their omnipresent impact on humans –  Pollinate most ﬂowering plant of Agric importance as well as transmits various diseases to man •  Mostly terrestrial sp. –  May live as adults on land and have aquaEc larvae •  If aquaEc, then fresh water, few are truly marine and others inhabit the shore between the Edes/saltwater November 9, 2012 ABCS 101 (Introductory Animal Biology) 64 mashes

65. Subphylum Uniramia Class Insecta •  INSECT CHARACTERISTICS •  Most insects share –  the same general body plan •  head, thorax and abdomen –  specialized mouthparts for feeding, –  a unique life cycle, and –  the ability to ﬂy –  Most insects have mouthparts for eaEng called mandibles. •  These specialized c(Introductory Animal Biology) mouth parts are omplex set of ABCS 101 adapted for chewing, sucking, or lapping November 9, 2012 65

66. Subphylum Uniramia Class Insecta •  In insects, the thorax is composed of three fused segments (3 disEnct tagma) -‐ A ﬂexible joint separaEng the head and thorax –  Three pairs of jointed walking legs (hexapods), emerging from and ajached to the thorax directed ventrally –  Usually two pairs of antennae of wings carried dorsally on the thorax •  Wings are out folding of the thoracic integument and consist of two thin chiEnuous sheets. •  One pair of antennae protrudes from the head, and the sense organs include both simple and compound eyes –  The main light receptors are the pair of compound eyes, but single-‐ unit eyes (ocelli)are usually present on the head as well •  Abdomen lacks appendages, except for a pair of sensory cerci borne on the last abdominal segment •  November 9, 2012 Communicate with each o01 (Introductory Adances” and by chemical ABCS 1 ther by “ nimal Biology) called pheromones. 66

67. Subphylum Uniramia Class Insecta •  May be described as an arEculated, tracheated, hexapod. November 9, 2012 ABCS 101 (Introductory Animal Biology) 67

68. Subphylum Uniramia Class Insecta • Legs may be modiﬁed for walking, jumping, swimming, digging or grasping, and are generally studded with a variety of sensory receptors, including receptors for taste, smell and touch •  such receptors are also found on the mouthparts and elsewhere on the body November 9, 2012 ABCS 101 (Introductory Animal Biology) 68

69. Subphylum Uniramia Class Insecta •  Head bears four pairs of appendages; –  one pair of uniramous antennae –  Three pairs of mouth parts November 9, 2012 ABCS 101 (Introductory Animal Biology) 69

70. Subphylum Uniramia Class Insecta In sequence, the mouthparts are the mandibles, the maxillae, and a pair of second maxillae that are fused to form a single appendage called the Labium. The mandiles are sheilded anteriorly by a downwards extension of the head called the labrum. (Introductory Animal Biology) November 9, 2012 ABCS 101 70

71. Subphylum Uniramia Class Insecta •  Morphology of these mouthparts varies considerably according to the insect’s feeding biology November 9, 2012 ABCS 101 (Introductory Animal Biology) 71

72. Subphylum Uniramia Class Insecta LocomoBon •  Movement in insects depends, as it does in vertebrates, on muscles contracEng and pulling on jointed limbs or other appendages. •  The muscles are within the body and limbs, however, and are ajached to the inside of the cuEcle. •  A pair of antagonisEc muscles is ajached across a joint in a way which could bend and straighten the limb. •  Many of the joints in the -‐insect are of the "peg and socket" type. •  They permit movement in one plane only, like a hinge joint, but since there are several such joints in a limb, each operaEng in a diﬀerent direcEon, the limb as a whole can describe fairly free direcEonal movement. •  Insects move by walking, jumping, running, swimming etc. November 9, 2012 ABCS 101 (Introductory Animal Biology) 72

73. Subphylum Uniramia Class Insecta Walking •  The characterisEc walking pajern of an insect involves moving three legs at a Eme. The body is supported by a "tripod" of three legs while the other three are swinging forward to a new posiEon. •  On the last tarsal joint are claws and, depending on the species, adhesive pads which enable the insect to climb very smooth surfaces. •  The precise mechanism of adhesion is uncertain. •  ModiﬁcaEon of the limbs and their musculature enables insects to leap, e.g. grasshopper, or swim, e.g. water beetles. November 9, 2012 ABCS 101 (Introductory Animal Biology) 73

74. Subphylum Uniramia Class Insecta Flying •  In insects with relaEvely light bodies and large wings such as bujerflies and dragonflies, the wing muscles in the thorax pull directly on the wing where it is arEculated to the thorax, levering it up and down. •  Insects such as bees, wasps and flies, with compact bodies and a smaller wing area have indirect flight muscles which elevate and depress the wings very rapidly by pulling on the walls of the thorax and changing its shape. •  In both cases there are direct flight muscles which, by acEng on the wing inserEon, can alter its angle in the air. •  During the down stroke the wing is held horizontally, so thrusEng downwards on the air and producing a liling force. •  During the upstroke the wing is rotated verEcally and offers lijle . resistance during its upward movement through the air November 9, 2012 ABCS 101 (Introductory Animal Biology) 74

75. Subphylum Uranimia Class Insecta ADAPTATIONS FOR FLIGHT •  Insects are adapted for flight by having a lightweight body, wings, and strong muscles to power flight. –  Insects were the first animals to have wings. –  Flight was a great evoluEonary innovaEon. Flying insects were able to reach previously inaccessible food sources and to escape quickly from danger. –  An insect’s wings develop from saclike outgrowths of the body wall of the thorax. –  Most insects have two pairs of wings. November 9, 2012 ABCS 101 (Introductory Animal Biology) 75

76. Subphylum Uniramia Class Insecta Feeding •  Insects feed on variety of nutriEve sources, including plants and animal Essues and on fluids •  It is not possible to make very useful generalizaEons about the feeding methods of insects •  their mouth parts, hinged to the head below the mouth, extract or manipulate food in one way or another –  modified and adapted to exploit different kinds of food source •  •  The basic pajern of these mouth parts is the same in most insects but in the course of evoluEon they have evolved. The least modified are probably those of insects such as caterpillars, grasshoppers, locusts and cockroaches in which the first pair of appendages, mandibles, form sturdy jaws, working sideways across the mouth and cupng off pieces of vegetaEon which are manipulated into the mouth by the other mouth parts, the maxillae and labium. November 9, 2012 ABCS 101 (Introductory Animal Biology) 76

77. Subphylum Uniramia Class Insecta •  Aphids for eg. feed on plant juices that they suck from leaves and stems. Their mouthparts are greatly elongated to form a piercing and sucking proboscis. The maxillae ﬁt together to form a tube which can be pushed into plant Essues to reach the food-‐conducEng vessels of the phloem and so extract nutrients. November 9, 2012 ABCS 101 (Introductory Animal Biology) Aphid mouth parts are elongated and modiﬁed to pierce plant Essue to suck up plant juices. 77

78. Subphylum Uniramia Class Insecta •  The mosquito has mandibles and maxillae in the form of slender, sharp stylets which can cut through the skin of a mammal as well as penetraEng plant Essues. •  To obtain a blood meal the mosquito inserts its mouth parts through the skin to reach a capillary and then sucks blood through a tube formed from the labrum or "front lip" which precedes the mouth parts. November 9, 2012 ABCS 101 (Introductory Animal Biology) 78

79. Subphylum Uniramia Class Insecta Feeding •  Another tubular structure, the hypopharynx, serves to inject into the wound a substance which prevents the blood from clopng and so blocking the tubular labrum. •  In both aphid and mosquito the labium is rolled round the other mouth parts, enclosing them in a sheath when they are not being used. •  In the bujerfly, only the maxillae contribute to the feeding apparatus. –  The maxillae are greatly elongated and in the form of half tubes, i.e. like a drinking straw split down its length. –  They can be fijed together to form a tube through which nectar is sucked from the flowers. November 9, 2012 ABCS 101 (Introductory Animal Biology) 79

80. Subphylum Uniramia Class Insecta Feeding •  The houseﬂy also sucks liquid but its mouthparts cannot penetrate Essue. Instead the labium is enlarged to form a proboscis which terminates in two pads whose surface is channelled by grooves called pseudotracheae. •  The ﬂy applies its proboscis to the food and pumps saliva along the channels and over the food. •  The saliva dissolves soluble parts of the food and may contain enzymes which digest some of the insoluble majer. •  The nutrient liquid is then drawn back along the pseudotracheae and pumped into the alimentary canal. November 9, 2012 ABCS 101 (Introductory Animal Biology) 80

81. Subphylum Uniramia Class Insecta Feeding •  The esophagus is highly muscularized and serves as a pump, moving food into a crop for storage and/or preliminary digesEon •  A proventriculus is generally present, funcEoning as a valve to regulate the passage of food and in some species to grind ingested food •  DigesEon and absorpEon occur in the mid gut and it associated gastric ceca •  The walls of the mid gut are olen lined by peritrophic membrane, as in the Diplopods (membrane is discarded and renewed periodically). •  SymbioEc bacteria and protozoans harboured in the gastric ceca of many species parEcipate in the digesEve process November 9, 2012 ABCS 101 (Introductory Animal Biology) 81

82. Subphylum Uniramia Class Insecta (a)  an insect (b)Sagijal cross secEon through a formica worker showing November 9, 2012 internal anatomy ABCS 101 (Introductory Animal Biology) 82

83. Subphylum Uniramia Class Insecta The alimentary canal of an insect Some insects may house receptors that monitor the degree to which the body is stretched during feeding November 9, 2012 ABCS 101 (Introductory Animal Biology) 83

84. Subphylum Uranimia Class Insecta ExcreEon •  ExcreEon is accomplished by 2 to many slender Malpighian tubules which receives metabolic wastes from the blood and aler concentraEng them, discharge them into the intesEnes •  Uric acid is the primary end product of protein metabolism among insects; this non toxic nitrogenous compound is excreted in nearly dry solid forms. •  Several mechanisms are involved in insect waste eliminaEon •  Many insects also posses nephrocytes as found in arachnids •  Before waste reaches the anus, most of the water is resorbed from the fecal material by the rectal glands of the hindgut November 9, 2012 ABCS 101 (Introductory Animal Biology) 84

85. Subphylum Uranimia Class Insecta November 9, 2012 ABCS 101 (Introductory Animal Biology) 85

86. ExcreBon Subphylum Uranimia Class Insecta •  Insects eliminate a signiﬁcant fracEon of their nitrogenous wastes as water-‐ insoluble uric acid and related compounds •  Such compounds are eliminated from the body in nearly dry forms, as most of the water in the urine is resorbed in transit through the rectum •  This is an outstanding physiological adaptaEon for terrestrial existence •  Waste products, notably a soluble derivaEve of uric acid, are acEvely transported from the blood into the distal porEon of the malpighian tubules •  Increased acidity in the proximal porEon of the tubules causes the uric acid to precipitate out of soluEon •  Most of the water contained in the urine is then resorbed during its passage through the rectum November 9, 2012 ABCS 101 (Introductory Animal Biology) 86

87. Subphylum Uranimia Class Insecta ExcreEon The major excretory organs are called Malpighian tubules ABCS 101 (Introductory Animal Biology) There are abt 250 pairs found in insect hemoceal November 9, 2012 87

88. Subphylum Uranimia Class Insecta Gaseous exchange •  One pair of spiracles opening into the tracheal system is found on the thorax, with addiEonal pairs of spiracles located on many of the abdominal segments •  The trachea are lined by a cuEcle, which is shed and resecreted by the underlying epidermia each Eme the insect molts, and the tubules are kept from collasping by means of chiEnuous rings embeded in the walls •  The trachae Essue branch to form a network of smaller tubules called tracheoles; which are less then 1 um in diameter. •  These branch again and terminate directly on the insect’s Essue. Thus, gas is exchanged between the Essues and the environment without the involvement of the blood circulatory system •  Some insects species lack trachea, either as iology) or during development ABCS 101 (Introductory Animal B adults 88 November 9, 2012

89. Subphylum Uranimia Class Insecta Gaseous exchange Largely terrestrial thus to cope, gas exchange have been internalized by means of tracheal system November 9, 2012 ABCS 101 (Introductory Animal Biology) 89

90. Subphylum Uranimia Class Insecta ReproducEon November 9, 2012 ABCS 101 (Introductory Animal Biology) 90

91. Insect CopulaBon –  • All insects have internal ferElizaEon –  • Most insects copulate ’normally’ •  – the male and female genitalia engage and sperm are –  transferred to site(s) of sperm storage. –  • Sperm maybe transferred free or in a sperm –  package -‐ spermatophore –  • Some species have ‘traumaEc’ inseminaEon •  – paragenital system •  – e.g. Cimicid bugs (bedbugs – Vägglöss) November 9, 2012 ABCS 101 (Introductory Animal Biology) 91

92. Subphylum Uranimia Class Insecta ReproducEon and development Most insects reproduce sexually 101 (Introductory Animal Biology) November 9, 2012 ABCS 92

93. Subphylum Uranimia Class Insecta Some reproduce asexually – Parthenogenesis – Aphids (Homoptera) November 9, 2012 ABCS 101 (Introductory Animal Biology) 93

94. Subphylum Uranimia Class Insecta Sexual reproducBon •  Sexes are separate and ferElizaEon is internal (several molts during development) INSECT LIFE CYCLE •  Insect development is unique among arthropods •  Insects have a unique life cycle compared with other arthropods. –  During development, a young insect undergoes metamorphosis. •  Metamorphosis is a dramaBc physical change, which can be complete or incomplete. November 9, 2012 ABCS 101 (Introductory Animal Biology) 94

95. •  Sexual reproducEon in insects –  Insect lifecycles -‐ three fundamentaltypes 1. Ametabolous – no metamorphosis 2. Hemimetabolous – incomplete metamorphosis (no pupal stage) There are several developmental stages called nymphal stages and gradual metamorphosis (change in body form) to the adult form 3. Holometabolous – full / complete metamorphosis with 4 disEnct stages in the life cycle; Egg – Larva – pupa – adult November 9, 2012 ABCS 101 (Introductory Animal Biology) 95

97. Subphylum Uranimia Class Insecta Incomplete metamorphosis •  •  •  November 9, 2012 A smaller number of insect species undergo incomplete metamorphosis. – During incomplete metamorphosis, the egg hatches into a juvenile, or nymph, that looks like a small, wingless adult. – A]er several molts, the nymph develops into a sexually mature adult. ABCS 101 (Introductory Animal Biology) 97

99. Subphylum Uranimia Class Insecta Complete metamorphosis •  In complete metamorphosis, the wingless larva grows in size and passes through a number of molts that are characterisBc for its species. •  – The four stages in a complete metamorphosis life cycle are the egg, the larva, the pupa, and the adult. November 9, 2012 ABCS 101 (Introductory Animal Biology) Almost all insect species undergo complete metamorphosis. 99

101. Subphylum Uranimia Class Insecta •  Insects are successful because –  Of numbers. More species than all other classes of animals combined. (what the lack in size, they make up in sheer numbers) –  They have an extra ordinary ability to adapt to changes in the environment (Believed they can inherit the earth) November 9, 2012 ABCS 101 (Introductory Animal Biology) 101

102. Subphylum Uranimia Class Insecta SECRETS OF THEIR SUCCESS –  Body plan modified and specialized in so many ways that insects have been able to adapt to an incredible number of life styles –  They have filled almost every variety of ecological niche –  Their ability to fly rapidly through the air •  Wings and small size facillitate their wide distribuEon –  Body is well proteced by tough exoskeleton, which also helps to prevent water loss by evaporaEon –  ProtecEve mechanism such as mimcry, protecEve coloraEon and aggressive behavior –  Metamorphosis divides the insect into different stages •  a strategy that has the advantage of placing larval forms into their own niches so that they do not have to compete with adults for food or habitats. November 9, 2012 ABCS 101 (Introductory Animal Biology) 102

103. Subphylum Uranimia Class Insecta –  Tremendous numbers of species largely ajributed to the feeding specializaEon, dispersal capabiliEes and predaEon avoidance possibiliEes associated with evoluEon of ﬂight (no other invertebrate and relaEvely few vertebrates sp., have evolved this capability) November 9, 2012 ABCS 101 (Introductory Animal Biology) 103

104. Subphylum Uranimia Class Insecta SOCIAL INSECTS •  What are the characterisBcs of social insects? •  Social insects have elaborate social systems involving specializaBon of labor, parental care, and communicaBon between individuals. –  The role that an individual plays in a colony is called a caste. –  Caste is determined by a combinaBon of heredity, diet, hormones, and pheromones. –  Social insects include honeybees and termites. –  A honeybee hive contains a queen, workers, and drone males. –  Termites have kings as well as queens. Workers gather the food, raise the young, and excavate tunnels. November 9, 2012 ABCS 101 (Introductory Animal Biology) 104

105. Subphylum Uranimia -‐ Class Insecta Female caste members of termites (a) Queen (b) Worker (c) Soldier (d) Secondary queens (e) TerEary queen November 9, 2012 ABCS 101 (Introductory Animal Biology) 105

106. Subphylum Uranimia Class Insecta •  Insect social systems encompasses many important issues in behavioral ecology and evoluEonary theory •  Many hymenopterans (ants, bees, wasp, termits) are eusocial (true social insects) –  They form colonies composed of more or less sterile workers and one or more reproducEve queens. •  Queens exhibit mulEple generaEons within a colony (protected and cared for by her oﬀsprings) •  Queens aler maEng loose their wings and build nests where she then lays eggs who forms the worker caste. November 9, 2012 –  Workers take care of the nest, care for the embryos and larvae, defend the nest and forage for food. –  Some workers develop into soldiers, morphologically and behaviorally 106 specialized for ABCS 101 (Introductory Animal Biology) defense and aggression.

107. Subphylum Uranimia Class Insecta •  CommunicaEon is through a complex system of mechanical and chemical cues. •  Males are produced only aler the colony has achieved a substanEal size, aler several years. –  The queen produces males delibrately, by releasing eggs without ferElizing them (haploid-‐ pathogeneEcs) »  Winged, do no work and are chased out of the colony by workers •  Some diploid embryo however develop into winged reproducEves (future queens) –  the quality of food and hormonal Etres are altered •  Males dies soon aler maEng and queens develop new nests thus iniEaEng new colonies November 9, 2012 ABCS 101 (Introductory Animal Biology) 107

108. Subphylum Uranimia Class Insecta •  Bees also exhibit social behaviors –  Workers are always diploid females •  Care for queens and oﬀsprings, scouEng out suitable nest sites, and controlling nest temperature –  These roles change as workers age (and exhibit altered hormonal concentraEons) –  Males are always haploid, do no work and are eventually expelled. –  Queens mate brieﬂy and store enough eggs to last a life Eme. November 9, 2012 ABCS 101 (Introductory Animal Biology) 108

109. Subphylum Uranimia Class Insecta •  Unlike ants and bees termits queens cannot control the sex of their oﬀsprings –  Workers may be males or females •  Both sterile and blind –  Workers in primiEve species are made up of developmentally arrested larval stages called Pseudergates (“false workers”) •  These can remain workers for life or metamorphose into winged reproducEves and ﬁnd new colonies, or into soldiers November 9, 2012 ABCS 101 (Introductory Animal Biology) 109

110. Subphylum Uranimia Class Insecta DIVERSITY •  Two sub class –  Apterygota-‐wingless insects •  Order Thysanura-‐ silverﬁsh or bristletail •  Order Collembola-‐ springtail –  Pterygota-‐ winged insects •  Abt 29 0rders November 9, 2012 ABCS 101 (Introductory Animal Biology) 110

111. •  Psocoptera (book lice, bark lice) Protura (small, wingless insects) •  Mallophaga (biEng lice) Collembola (springtails) •  Siphunculata (sucking lice) Thysanura (silverfish) •  Hemiptera (true bugs) Diplura (bristletails) •  Thysanoptera (thrips) Ephemeroptera (mayflies) •  Neuroptera (lacewings, antlions, Odonata (dragonflies, damselflies) manEs flies) Plecoptera (stoneflies) •  Coleoptera (beetles) 300 000 spp Grylloblatodea (grylloblajas) •  Strepsiptera (stylops) Orthoptera (crickets, grasshoppers, •  Mecoptera (scorpionflies) locusts) •  Siphonaptera (fleas) •  Phasmida (sEck insects, leaf insects) •  Diptera (true flies, mosquitoes) •  Dermaptera (earwigs) •  Lepidoptera (bujerflies, moths) 200 •  Embioptera (embiids) 000 spp •  Dictyoptera (cockroaches, manEds) •  Trichoptera (caddis flies) •  Isoptera (termites) •  Hymenoptera (bees, ants, wasps, 111 November 9, 2012 ABCS 101 (Introductory Animal Biology) •  Zoraptera (terrestrial lice) hornets) 100 000 spp •  •  •  •  •  •  •  •  • 

112. Subphylum Uranimia Class Insecta •  •  •  •  •  •  •  •  •  November 9, 2012 (a) An aperygote (b) frui~ly (c) leaf cujer (d) mosquito (e) Bujerﬂy (f) Termites (g,h) beetles (i) grasshopper (J) larvae of a caddisly ABCS 101 (Introductory Animal Biology) 112

113. Subphylum Uniramia Class Insecta Insect diversity •  Insect orders November 9, 2012 ABCS 101 (Introductory Animal Biology) 113

114. Insect order populaEons in relaEon to life on earth November 9, 2012 ABCS 101 (Introductory Animal Biology) 114

115. ARTHROPODA Subphylum Crustacea Class Malascostraca Class Ostracoda Class Copepoda Class Cirripedia Class Pentastomida (Biramous appendages: branched appendage with 2 pairs of antennae) November 9, 2012 ABCS 101 (Introductory Animal Biology) 115

116. SUBPHYLUM CRUSTACEANS November 9, 2012 ABCS 101 (Introductory Animal Biology) 116

117. CRUSTACEANS –  bilateral symmetry –  eucoelomic (true coelom) –  high degree of cephalizaEon = well developed head with sensory organs –  specialized segmentaEon (metamerism) = tagmata –  triploblasEc structure (endoderm, mesoderm and ectoderm) –  all organ systems are present November 9, 2012 ABCS 101 (Introductory Animal Biology) 117

118. SUBPHYLUM CRUSTACEANS CRUSTACEANS •  Like chelicerates, crustaceans have appendages on their abdomen •  Unlike chelicerates, crustaceans have mandibles that are adapted for feeding and have two antennae –  Some crustaceans are sessile, which means that they are permanently ajached to something. •  Barnacles are an example of a sessile crustacean. November 9, 2012 ABCS 101 (Introductory Animal Biology) 118

119. most crustaceans have between 16 and 20 segments some have many more •  ! different segments in different groups may have fused to form a head or cephalothorax •  crustaceans have a cephalothorax and an abdomen •  ! head fused to thoracic body segments to form a cephalothorax •  ! abdomen is formed of the posterior segments •  ! telson (tail) with uropod •  ! first walking leg is chelate (cheliped) •  ! two pairs of antennae (one pair of antennae and one pair of ABCS 101 (Introductory Animal Biology) 119 antennules) •  November 9, 2012

120. SUBPHYLUM CRUSTACEANS •  The two pairs of antennae are the sites of chemoreceptor and tacEle sense organs, the 2nd pair of antennae are especially long. •  ! one pair of mandibles (crustaceans are the aquaBc mandibulates) –  Mandibles are short and heavy with the opposing surface used in grinding and biEng of food •  ! two pairs of maxillae on the head –  Behind the mandibles are two pairs of accessory feeding appendages, the ﬁrst and second maxillae. •  The appendages of the ﬁrst 3 segments of the thorax are the maxillipeds, which aid in chopping up food and passing it to the mouth. •  The 4th segement of the thorax has a pair of large chelipeds or pinching claws November 9, 2012 ABCS 101 (Introductory Animal Biology) 120

121. SUBPHYLUM CRUSTACEANS •  The last four thoracic segments have pairs of walking legs •  The appendages of the first abdominal segment are part of the reproducEve system and funcEon in the male as sperm – transferring structures. •  The four abdominal segements are paired swimmerets, small paddle-‐like structures used by some decapods for swimming and by females of all species for holding eggs. •  Each branch of the sixth abdominal appendages which are called uropods; consists of a large flajened structure together with the flajened telson,the posterior end of the abdomen, they form a fan-‐shaped tail fin used for swimming backwards. November 9, 2012 ABCS 101 (Introductory Animal Biology) 121

122. •  ! usually one pair of appendages on each body segment •  ! all appendages except the ﬁrst pair of antennae in present-‐day crustaceans are biramous (two-‐branched) •  •  ! body is covered with secreted cuBcle of protein, chiBn and calcareous material •  ! cuBcle is thinner around joints for movement –  ! tergum is the dorsal cuBcle plate on each segment not covered by carapace –  ! sternum is the ventral cuBcle on each segment November 9, 2012 ABCS 101 (Introductory Animal Biology) 122

123. –  Almost all crustaceans have a disEncEve larval form called a nauplius. –  Isopods are the only crustaceans that are truly terrestrial. Pill bugs are examples of isopods. –  Some aquaEc crustaceans are quite small. •  Common examples include fairy shrimps, water fleas, and copepods. –  Another small marine crustacean, commonly known as krill, is the chief food source for many marine species. •  •  •  •  •  mainly marine, many freshwater, a few are terrestrial ! Class Malacostraca is the largest group (lobsters, crabs, shrimps, beach hoppers and many others) ! walking legs, mouthparts, chelipeds and swimmerets have all become modified for different funcEons from a common biramous appendages (they are serially homologous) ! crustaceans have segmented nervous and muscular systems November 9, 2012 ABCS 101 (Introductory Animal Biology) 123

124. •  Senses sense organs include: compound eyes formed of ommaBdia, tacBle hairs (especially •  on chelae and mouthparts and telson); chemoreceptors for taste and smell on •  antennae, mouthparts and other places; statocysts open on dorsal side at the base of •  each first antennae (in crayfish) with chiEnous lining and sand grains that act as •  statoliths which are replaced a]er each molt •  ! Each hexagonal ommaBdia of the eye is covered by a transparent part of the cuBcle = •  cornea; each ommaBdia acts as a “Bny eye” with pigment cells between them that •  form a collar to separate ommaEdia; in bright light, each ommaBdia only “sees” a •  limited area of the field of view to form a mosaic image; at night, distal and •  proximal pigment cells can separate so light hits mulBple reBnal cells in mulBple •  ommaEdia to form a superimposed conEnuous image that is not mosaic, but less November 9, 2012 ABCS 1 124 •  precise – this makes the most o01 (he limited available light at night f t Introductory Animal Biology) • 

125. •  Feeding •  Feeding Habits of Crustaceans •  ! much variaEon in feeding habits of crustaceans and some can shil feeding strategies (eg. •  pistol shrimp use their enlarged chela to snap shut very fast and form a cavitaEon bubble •  that can stun prey) •  ! chelipeds are used in prey capture and mandibles and maxillae and other mouthparts used •  in ingesEng food •  ! crustaceans can be suspension feeders, predators or November 9, 2012 ABCS 101 (Introductory Animal Biology) 125 scavengers

126. •  ExcreEon •  •  •  •  •  •  •  •  •  •  •  •  green/antennal or maxillary glands depending on where they open at are paired tubular structures for excreEon; crustaceans lack Malpighian tubules ! freshwater crustaceans have green glands that form a dilute low-‐salt urine for osmoEc balance; some salt is lost with the urine but is replaced by salt absorpEon through the gills (lijle nitrogenous waste is actually excreted by the green glands) ! excreBon of primarily ammonia occurs primarily by diﬀusion across thin areas of the cuBcle and gills ! marine crustaceans have kidneys for salt and water balance (osmoregulaBon) ! nervous system is composed of a pair of supraesophageal ganglia with nerves to the eyes and two pairs of antennae which is joined to a subesophageal ganglion with nerves to the mouth, appendages, esophagus and antennal glands; paired ventral nerve cords with a pair of ganglia in each segment and peripheral nerves to appendages, •  muscles, etc November 9, 2012 . ABCS 101 (Introductory Animal Biology) 126

127. RESPIRATION •  Crustaceans breathe by using gills •  ! eﬃcient gills for respiraBon November 9, 2012 ABCS 101 (Introductory Animal Biology) 127

128. •  CirculaEon •  “open” circulatory system with blood leaving the dorsal heart through short arteries •  to the hemocoel and back to the heart through venous sinuses; arteries possess valves •  to prevent backﬂow •  ! hemolymph may be colorless, reddish or bluish due to hemocyanin (copper containing •  respiratory pigment or hemoglobin (iron containing respiratory pigment); hemolymph •  can clot to prevent loss in minor injuries and ameboid cells release November 9, 2012 clopng proteins (Introductory Animal Biology) ABCS 101 128

129. ReproducEon •  gonopore posiBon varies usually near the 5th pair of walking legs in males & the 3rd pair of walking legs in females; opening to the seminal receptacle is near the 4th and 5th pairs of walking legs in females •  ! considerable specializaEon of appendages has occurred in many derived groups such as the crayﬁshes •  •  •  •  •  •  •  •  most crustaceans have separate sexes with specializaBons for copulaBon and ways of brooding their eggs ! barnacles are monoecious but uBlize cross-‐ferBlizaBon with other individuals via a very long penis (relaEve to body size) as sessile adults ! ostracods and some copepods are o]en parthenogeneBc ! the ancestral most common type of larva in crustaceans is a nauplius larva with three pairs of appendages, uniramous ﬁrst antennules, biramous antennae and biramous mandibles all used for swimming with gradual changes to an adult form through a •  series of molts or only a fews molts (eg. barnacles) November 9, 2012 ABCS 101 (Introductory Animal Biology) 129

130. SUBPHYLUM CRUSTACEANS •  •  •  •  •  •  Class Malacostraca Class Branchiopoda Class Ostracoda Class Copepoda Class Pentastomida Class Cirripeda November 9, 2012 ABCS 101 (Introductory Animal Biology) 130

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