Lecture 20 Flashcards
ectoparasite
an organism which spends much of its adult life in close assoc with the habitat created by the skin & its outgrowths of mammals & birds or with the host’s nest or roost, possessing obvious adaptations to its habitat and deriving its food from its host
why is a cockroach not a parasite?
not in close assoc
why is a mosquito not a parasite?
not in close assoc
what are the 2 grps of ectoparasites in Canada not well studied?
lice & mites
what are the characteristics of all lice? (7)
Ectoparasites of birds/mammals
Hemimetabolous
Wingless
Dorso-ventrally flattened – enables movement among feathers or hairs
Backward-directed setae – facilitates movement through feathers
Eggs cemented to hairs/feathers
3 juvenile instars
what are the characteristics of sucking lice?
Sucking mouthparts
Tarsal claws (one/leg; some large) – OT
Blood-feeders only; mammals only
what are the characteristics of chewing lice?
Chewing mouthparts
Tarsal claws (always small)
1 claw when parasitic of mammals – OT
2 claws when parasitic on birds – OT
Feed on hair/feathers &/or blood consumed
Rhynchopthirina
parasites of elephants, rhinos & warthogs
Laemobothrion
largest chewing lice
Nosopon lucidum
smallest chewing lice
where do lice attach?
thickest hairs of their host
what adaptation do sucking lice from seals have?
hairs are modified into scales
direct contact
one host is physically against another one
what are the methods of dispersal in lice?
direct & indirect contact
what are the 4 ways of direct contact in lice?
parent to offspring (vertical)
during roosting (horizontal)
during mating (horizontal)
allogrooming (horizontal)
parent to offspring dispersal of lice is done in what animals? (2)
great grey owls, royal albatross
roosting dispersal of lice is done in what animals?
roosting broadgulls, emperor penguins
indirect transfer
hosts don’t come close to each other
what are the ways of indirect contact in lice?
phoresy
fomites
what is a method of human-assisted dispersal of lice?
fomites
what does horizontal transfer of lice mean?
occurs outside the nest
what is the method of vertical transfer of lice?
parent to offspring
how do chewing lice latch onto their host?
latch on to hairs & feathers with exerted mouthparts
how do sucking lice latch onto their host?
with tarsi since their mouthparts are not exerted
why are birds an attractive host to lice?
have a variety of feather thicknesses
why do lice lay eggs in hairs?
ensures the attachment of their eggs
describe pelican lice
Males exist in pouches
When teneral female emerges, the males latch on to the female
Mate with female, release her
Female leaves pouch & goes back to feathers to lay eggs
Looks like the pouch is for mating
what were the benefits of prof’s study? (5)
Host diversity (275 spp.)
Sample size
Geographic distribution
Total ectoparasite pop - good quantitative data
No animals sacrificed
what were the disadvantages of prof’s study? (6)
Sample sizes
Geographic distribution
Sample bias – lice are free to feed on dead hosts
Deficiencies in collection data
Cross-contamination
Spatial distribution lost
