W9&10 Phylum Arthropoda. Class Insecta. Flashcards
Class Insecta characteristics
body= head, thorax, + abodmen; 3 pairs of walking legs. pair of lrg compound eyes pair of antennae on the head; 2 pairs of wings in thoracic segments
what is Ametabolous development
Hatching eggs produce miniature copies of adults which increase size and shed exoskeleton Ecdysis. NO metamorphosis
what is Hemimetabolous development
Newly hatched are similar to adult but smaller in size +lack wings.sexually immature
incomplete metamorphosis HAS NYMPH STAGE
what is Holometabolous development
Newly hatched= completely different from adults . larval forms live in diff habitats. Larval stage= complete it stops feeding and builds cocoon around itself
HAS PUPA STAGE
Lava undergoes metamorphosis of organs fully formed adult.
Class Insecta Digestive system
closed. 3 part: foregut, midgut, hindgut
Complex digestive tract.
glands producing digestive enzymes+ anticoagulants.
mouthparts, related to their feeding habits.
Class Insecta circulation
open.
hemolymph confined to vessels. throughout rest of body it flows freely through body cavity. (hemocoel)
dorsal vessel acts as heart. it pumps hemolymph through the sinuses of the hemocoel.
DO NOT CARRY O2
Class Insecta respiration
tracheal system. air enters through spiracles. aquatic has gills
body muscles involved
Class Insecta excretion
Malpighian tubules remove nitrogenous waste from hemolymph. they work w/ hind gut
Class Insecta nervous
ganglia+ ventral double spinal cord
dorsal brain= linked to ventral nerve cord (paired ganglia)
CNS- most ganglia- brain+SC
peripheral nerve system: sensory neurons, sense organs-eye, sensitive to sound, sensitive to chemical
Class Insecta Reproduction
2 sexes, fertilization= internal
male locates female through chemicals (pheromones).
females store sperm in a special receptacle in abdomens
females mate only once and rely on sperm stored during that mating for the rest of their lives.
what are Pediculus humanus known as?
what are the types, habitat
head louse- doesn’t transmit infections
inhabits head w/ hair
body louse- transmits typhus
found in clothes+ underwear
Pediculus humans morphology
- female= 4mm, lrg eggs seen in abdomen, post end=bifurcated
- male= 3mm, copulatory organ reach post end= rounded
- body:covered by yellow/ brown chitinous exoskeleton
6 legs that end w/ curved chitinous claws- attach to hair
they are doors-ventrally flattened+ NO wings
EGG= ‘nits’: Females lay 3-4 eggs per day.
To attach an egg, the adult female secretes a glue from her reproductive organ.
egg = oval-shaped, 0.8mm
Pediculus humanus Transmission
direct contact w/ infected person, sharing louse-infected clothes
Pediculus humanus causes
transmitted diseases
pediculosis- severe itching, redness
Louse-borne Typhus = rickettsial disease .caused by “Rickettsia prowažeki”
it inhabits louse digestive
tract.
Relapsing fever caused by “Borrelia recurrentis” . It inhabits the louse hemolymph.
Pediculus humanus life cycle
nits= headlice egg
1) nits laid by adult female near scalp.
2) eggs hatch + release nymph. they mature after 3 molts+ become adults(6 legs)
3) they feed on blood several times to survive. w/o blood they die
3 NYMPH STAGE
What is Phthirius pubis known as?
crap louse or pubic louse-
doesn’t transmit diseases