parasites

Question 1

define parasitism

Answer 1

relationship between two species where one species (parasite) benefits at the expense (unkosten) of the other (host).

Question 2

what is the difference between a macro and a micro parasite?

Answer 2

macropasite= you can see them 
micro = you dont

Question 3

give an example for a group of macroparasite

Answer 3

crustaceans, nematodes

Question 4

give an example for a group of microparasite

Answer 4

protozoa, fungi, bacteria, viruses

Question 5

what is an ectoparasite?

Answer 5

a parasite whcih lives on the oustide of the host

Question 6

what is an endoparasite?

Answer 6

a parasite which lives inside the body of the host

Question 7

endoparaistes are divided into? - what is difference between these two groups ?

Answer 7

intercellular: inside body cavities of the host
intracellular: inside cells of the host

Question 8

what are parasites called that depend on the host to complete its life cycle?

Answer 8

obligate parasites

Question 9

what are the parasites called that do NOT depend on the host to comlete its life cycle?

Answer 9

facultative parasites

Question 10

what is and indirect parasite

Answer 10

a parasite which has multiple hosts (multiple life stages).

- at least one or more intermediate and one definitive host

Question 11

what is a direct parasite?

Answer 11

a parasite which only has one host in in his life

Question 12

what is the difference between a generalist parasite and a specialist parasite?

Answer 12

a generalist can live on any host- not specialized on one species.

a specialist only has few species, on which he can live on.

Question 13

what are some problems with estimating marine parasites?

Answer 13

• effects of depth gradients
• ”-“ of hosts (same paraiste live on different hosts)
• ”-“ latitudinal/longitudinal gradients
• geographical variation
• lack of surveys
• intermediate forms

Question 14

what is the total estimate of all marine fish parasites?

Answer 14

about 100 000 species

Question 15

what are some problems in estimating the richness of free living orgainsms

Answer 15

• more than one species concept

- mainly studies on animal kingdom but rarely on microorganisms

Question 16

what is prevelance?

Answer 16

proportion (verhältnis) of infected hosts among all the hosts examined

Question 17

what is mean intensity?

Answer 17

mean number (mittelwert) of parasites found in/on the infected hosts.

Question 18

“host specificity” :

what does it take into account?

Answer 18

takes prevelance and/or intensity of infection into account

Question 19

does specifity will vary with the number of host species the parasite may live on/in?

Answer 19

yes

Question 20

si(intensity)
what is the highest number of host specifity?
-what doesn it say abou the host specifity of the parasite?

Answer 20

1

–> parsite only on one host!

Question 21

Rhodes index of specifity, what does is calculate?

Answer 21

used to calculate how specific a parasite is.

–> “Host specifity “

Question 22

how can rhodens index of specifity be used to measure site specifity?

Answer 22

by exchanging the number of hosts with number of sites

Question 23

what is site specifity?

Answer 23

parasites prefer certain microhabitatse over others. specifity varies between species.

Question 24

give an example for site specifity

Answer 24

two differnet species prefer different sites on the gill (kiemen) of the host.

Question 25

the number of different parasite species does not effect the site where they live on the organisms .
true or false?

Answer 25

true

Question 26

the number of the same species does not effect the site where they live on the organisms .
true or false?

Answer 26

false

- same species does affect the site.

Question 27

do interspecific factors or intraspecific factors effect more the site resitriction of a parasite?

Answer 27

intraspecific factors

Question 28

ecological concepts: what is equilibrium ?

Answer 28

maintaining the homoeostasis of an ecosystem, stable community.

Question 29

ecological concepts: what is non-equilibrium ?

Answer 29

competitive exclusion is prevented due to disturbances that prevent a stable community.

Question 30

parasites:

is equilibrium or on-equilibrium preferred

Answer 30

evidence or both, but non-equilibirum seems to be more prefered.

Question 31

what is a metapopulation?

likely for parasites or not?

Answer 31

a group of connected population of the same species.

- yes, likely.

Question 32

give an example for a metapopulation

Answer 32

gyrodactylidae species
lives on salmon and multiplys on it, when getting in contact with other affected salmon, the may jump over – > gene interaction.

Question 33

what effects can a parasite have on his host?

Answer 33

• changes in behaviour

- changes in the host community (shifts in mean valous of traits)

Question 34

how does high/low prevelance may affect the normal distribution of a trait in the host community?

Answer 34

high prevelance: displace normal distribution

low prevelance: distribution may become skewed (verschoben)/ shifted

Question 35

parasite in mariculture -why important?

how can parasites be used ?

Answer 35

• as biological markers –> to differnciate between host populations
• -> used to control introduced species
• as indicator for migration
• used for pollution monitoring –> pulltion indicators
• can be used to monitor ecosystem health
• used to control introduced species
• used

Question 36

why cas parasites be used for poulltion monitoring?

Answer 36

• more parasites than free living species
• several lifstages –> that are particulary sensitive to environmenatl change
• accumulation of heavy metals , may be higher than in host tissue/environment
• indirect parasites can only survive in habitats where all their hosts can survive (–> indirect ore sensitive)

Question 37

environmnetal stress can have different effects on the parasites impact on his host.
name a few

Answer 37

• pollution may increase the suspectibilty to parasites
• pollution may decfease parasitsim, by causing higher host mortality
• habitat alteration may lead to incfeased or decreased paraistism
• introduction of new species–> introduction of new parasites; native species might be less resistent to the new parasitses

Question 38

what are ecosystem services of parasites?

Answer 38

• regulate host abundance–> keeping it under the ecosystem carrying capacity
• -> may allow other species to compete in the same area, creating nisches
• more complex and tight food web –> more resitent

Question 39

give some examples for parasites and diseases due to parasites in norwegian aquaculture

Answer 39

• “costia” (costyl for salmon industry- ichthyobodea necator causes breathing problems)
• AGD (amobic gill disease)
• whirling disease (codfish&polychaeta, parasite= myoxbolus cerebralis)
• plathelminthes (flatworms) (e.g. bendelmark)
• grodactylus salaris

Question 40

gyrodactylus salaris:

some facts

Answer 40

• ectoparasite of salmon
• lives in the freshwater base
• feeds on the salmon–> creates osmotic problems

Question 41

what is a hyperparasite?

Answer 41

a parasite of a parasite

Question 42

how many norwegian rivers have been infected by gyrodactylus salaris?

Answer 42

• 43 rivers have been infected

- 11 have been cleared

Question 43

with what can gyrodactylusl salaris be treated with?

Answer 43

rotenone treatment
(=insecticide, pesticide, piscicide)