Exam 1: Arthropods & ticks Flashcards
members of populations or groups of organisms that actually or potentially interbreed in nature and produce viable, fertile offspring
biological species
a group of closely related species that look almost identical but different genetically, behavior, life history
cryptic species complex
ex. house mosquito complex
males and females have distinctly different appearances
sexual dimorphism
ex. antennae of mosquitoes, eye size of many flies
what are the visible characteristics of phylum arthropoda
a. segmented body and appendages (legs, antennae)
b. hard external skeleton of chitin - tough, flexible polysaccharide (sugar) containing nitrogen
Name the 5 major groups of arthropod
- Crustacea - pillbugs, crayfish, shrimp
- Arachnida - ticks, mites, spiders
- Chilopoda - centipedes
- Diplopoda - millipedes
- Insecta - flies, lice, etc.
2 pairs of antennae, 2 main body regions, 5 pairs walking legs, scavengers, some predators, mostly marine aquatic
crustacea
No antennae, 4 pairs of walking legs, 2 main body regions (may look like 1), mostly terrestrial - predators, parasites, herbivores, etc.
arachnida
1 pair antennae, 2 body regions - head and trunk with many segments, 1 pair appendages per segment
1st segment - fangs, others are legs, flattened body - long legs, terrestrial predators - venomous bite
chilopoda (centipedes)
1 pair antennae, 2 body regions - head and trunk with many segments, 2 pair short legs per trunk segment, cylindrical body, terrestrial herbivores, scavengers
diplopoda (millipedes)
1 pair antennae, 3 main body regions, 3 pairs of legs, may have wings, mostly terrestrial - many feeding strategies
insecta
reasons for arthropod success
~many have complete metamorphosis
~high repro rate w/ 100’s - 1000’s of young per female
~most species w/ winged adults - dispersal
~small
~short life cycles
~high genetic diversity among individuals - rapidly adaptable
what is & types of metamorphosis
change in form
gradual and complete
gradual metamorphosis
egg, nymph, adult
most arthropods, some insects
complete metamorphosis
egg, larva, pupa, adult
most insects
advantages of exoskeleton
protection, strength (muscle support and leverage), conserve water
disadvantages of exoskeleton
heavy (limits growth and body size), reduced mobility, very limited damage repair, hard to detect external stimuli
molting
shed old, outgrown covering
old exoskeleton splits along lines of weakness, use blood pressure or air to expand before hardening
what controls metamorphosis
hormones - molting hormone tells the insect when to molt and grow
the level of jubenile hormone in blood determines
stage after a molt
immature or adult insect becomes adult if the JH level is below a certain value
how many times does a species molt?
4-8; more if under stress
instar is a term for
an immature
dangerous time
how do insects detect stimuli
palps (taste buds) - often final step in host selection
compound eyes- many lenses- large eyes and many small lenses = better vision
touch-body hairs
antennae (nose) - chemical odors - airborne or contact, on host, on each other; large antennae usually = greater reliance on chemicals/odors
argasidae
soft ticks; no hard plate on back; most species feed on birds; less important than hard
ixodidae
hard ticks;sclerotized plate back covers entire back of male, part of back of female; mostly mammal hosts
ticks classification
phylum: arthropoda
class: arachnida
order: acarina
family: argasidae or ixodidae
list some tick impacts
parasites - all species are blood feeders
stress to host - irritation, anemia
allergic reactions to injected substances by host - many substances injected during feeding: vasodilators, anti-coagulants, pain suppressors
feeding wounds - maggot attack, secondary infections; transfer pathogens (vectors) - 2nd to mosquitos
anemia, tick paralysis
ticks develop through what type of metamorphosis
gradual
tick life strategy
high fecundity (fertility) offsets low survival thousands of eggs produced by a female but mortality through development is high
life stages of the tick
egg and 3 life stages - larva (seed tick) 6 legs; nymph 8 legs; adult 8 legs
each immature stage has a blood meal, digests it and molts
how much time does the tick spend off host
95+ % of its life is on ground
tick survival
find shelter from direct sun - move to best microenvironment
absorb water form air (mouthparts) if humidity is high enough
find host and mate
key environmental elements for ticks
temp, rainfall, protection
1 host tick
larva finds host - entire life cycle completed on that host
engorged female drops off to lay eggs
3 host tick
each active stage independently finds a host - may be different species each time
main factors in order for tick to finding hosts
CO2
vibration of substrate from host movement
body heat
host-produced substances-constituents of sweat and skin lipids - HOST SPECIFICITY - often in final decision
vision-very limited
how to sample for ticks
tick traps, host traps, flagging
where are the life stages of ticks distributed
larvae - clumped where egg mass was deposited
nymphs & adults - single and more dispersed depending where they drop; may be clumped along host trails or bedding sites
how do ticks attach
cut skin and insert hypostome and anchor with ‘cement’
what prevents blood clots when ticks attach
saliva
how long does attachment occur for disease transfer
24-36 hours
when do ticks detach and drop?
where chances of finding another host are high
ticks usually drop off
when hosts are inactive - after nightfall or during day for nocturnally active hosts
reactions to saliva, capillary dilators, and anticoagulants are related to
tick bite allergies
red meat allergy is associated with what kind of tick
lone star
red meat allergy occurs
in susceptible individuals after multiple tick bites
what is the suspected cause of red meat allergy
antibodies to a sugar (alpha-gal) produced in persons blood after multiple LST bites
what are the characteristics of an efficient disease vector
obligate blood feeders
feed several times
feel slowly ( time to aquire a pathogen )
long life
protect and take pathogen to a susceptible host
pathogens may multiply in vector
tick removal
grab at skin and use steady pull
most important factors in avoiding tick-borne diseases
common tick that is relatively rare in KY
black legged tick
common tick-most important disease vector
american dog tick
important nuisance tick
lone star tick
common tick that is in kennels - only tick that can live and multiply indoors
brown dog tick
tick borne disease, one of several bacterial diseases that affect humans and animals but rare
Erlichiosis
primary vector and symptoms of erlichiosis
lone star tick
headache, feer, muscle aches within 1-2 weeks of bite
this tick is the vector of rocky mountain fever
american dog tick
what intracellular bacterium causes rocky mountain fever?
rickettsia
reservoirs of rocky mtn spotted fever
opossums, rabbits, chipmunks, squirrels, rats and mice
rickettsia becomes virulent only after how long of a time period of tick attachment?
> 10hours
vector of lyme disease
blacklegged tick
bacterium of lyme disease
borrelia burgdorferi
reservoirs of lyme disease
mostly white-footed mouse, shrews, chipmunks
where are blacklegged ticks seen
eastern and south and north central us
what are 3 main tick management practices
habitat management
reduce immigration
acaricide applications
