Help
Options
Didn't know it?
click below
click below
Knew it?
click below
click below
Don't Know
Remaining cards (0)
Know
retry
shuffle
restart
0:00
Embed Code - If you would like this activity on your web page, copy the script below and paste it into your web page.
Normal Size Small Size show me how
Normal Size Small Size show me how
Parasite/pathogen
Host manipulation
| Question | Answer |
|---|---|
| Why manipulate? | - extending parasite surival - castration of host to conserve energy spent on reproduction |
| Why manipulate? Gigantism | Resources are strategically reallocated to invest into host body growth, maintenance and survival ensuring longer infective period for the parasite a means of ensuring storage of resources from the host for the parasite to use later |
| Why manipulate? Increasing transmission | - improve host transmission - changing host behaviour and morphology |
| Transmission routs | - manipulate your current host to ensure the next generation of parasites is released in an advantageous place - manipulate your host to ensure you reach your next intermediary |
| Changing host behaviour - transmission site | ie. Cordyceps fungus Ants infected fall down a lot more Movement is less directional Death grip accompanied by muscle atrophy around the mouth |
| Changing host behaviour – finding the next intermediary | e.g. Toxoplasma Behavioural changes associated with inflammation of the brain due to cysts |
| Changing host morphology | - colouration and odour ie. land snails and certain ants |
| Changing host morphology - feminisation | - Typically increases vertical transmission down the female line - Generally transmitted vertically by the female through eggs to the progeny – although horizontal transfer is possible |
| Wolbachia in nematodes, insects and crustaceans | Wolbachia may kill or feminise males in the embryonic or larval stages or induce thelytokous parthenogenesis where virgin females produce daughters This alters sex ratios in the progeny in favour of females which ensures higher transmission rates |
| Wolbachia in nematodes, insects and crustaceans | Cytoplasmic incompatibility also means infected females have a reproductive advantage over uninfected females |
| Cost of manipulation | Nothing is free Development of manipulatory traits may come at the cost of another trait |
| Dinocampus coccinellae - parasitoid wasp of ladybirds | - Females deposit a single egg inside the haemocoel of the host and larvae feeds on host tissue - Host is however not killed during larval development |
| Dinocampus coccinellae - parasitoid wasp of ladybirds | - The larvae will emerge and spin a cocoon between the ladybirds legs - Wasp cocoons attended by manipulated but living hosts showed differences in predation and length of manipulation period impacted fecundity but not longevity |
| Liver fluke | - Ants become infected when they eat parasite infested slime balls from snails - When in the ant most flukes infest the hemolymph but one individual migrates to the ants brain – the brain worm |
| Liver fluke | - When the evening comes infected ants leave the colony and climb blades of grass waiting to be eaten by the definitive host - When day comes though infected ants that have not been consumed behave normally until evening again |
| The brain worm | The brain worm however won’t develop into infectious stages – so wont benefit from manipulations |
Created by:
rose.coo
Popular Ecology sets