19+20 infection and behaviour Flashcards
Main topics 6
1) Mate attractiveness
2) Indirect gene benefits and models
3) Sickness behaviour responses
4) Parasitic manipulation of behaviour of transmission
5) Malaria
6) Fungus and zombie ants
Mate attractiveness signals relates to immunity 3
Visual
Acoustic
Chemical (sexy signals)
Visual signals and immunity 2
Banded danselfly- darker wing spots mean lower load
House finch - dull plumage means parasitic mites and pox lesions
Acoustic sign of immunity
Wolf spiders
High drumming means high encapsulation which means high immune function
Chemical sign of immunity sexy signals
Beetles
Females prefer pheromones from males that indicate
a)high encapsulation rate
B) phenol oxidase response to immune insult
Why this association between smell for encapsulation and phenol oxidase response with being sexy?
M can maintain signal despite immune deficiency or this is a signal for immunity
So
Less likely to be carrying infection- which could directly affect f
Like to carry genes that will increase odd Spring fitness or confer resistance
What are the two hypotheses for indirect gene benefit
Good genes
Parasite mediated model of sexual selection
Good genes hypothesis
That broad threat from parasites / pathogens mean genes affecting immunity are good candidates for “good genes” so m will inherit chargerr females are selecting for and females will inherit preference for them
Problem - if the chosen mate then gave considerable offspring fitness advantage then genetic variation would be difficult to maintain??
Parasite mediated model of sexual selection
Hamilton and zuk
Explains gen variation
When parasite 1 common m1 preference spreads then when areas it’s 2 common this preference spreads
Sexual displays are reliable indicators of gen resistance and resistance is genetic
How do females distinguish sexy males that are immune 4
1) bright plumage and fur
2) bare patches of skin to assess blood
3) contests and fights
4) exhausting athletic displays
How to test sexual selection parasite hypothesis
Need to know parasite load in hosts
Need to know phenotypic markets used in female choice
If hypothesis is true those with most evident sexual selection will be most subjected to depilating parasites
Sexual selection parasite model example of spp
Female sticklebacks
Use make coloration in mate choice
Prefer bright red spots
When used green light couldn’t see red and this red preference was lost
When males infected with fungus have white spot and dull
Therefore redness of father predicts offspring resistance to infect
Infection causing sickness and am adaptive response by the host - intro - can cause 5
Behaviour change could be adaptive response ie
Increase sws
Decrease activity
Decrease appetite
Physiological changes he deplete plasma iron
Thermoregukagir set point
Main two things for infection and animal behaviour
Anorexia
Self medication
Anorexia 3 animals
Hedgehogs - foot and mouth disease
Mice - if forced to eat higher mortality and survivors if allowed to choose had lower body weight
Crickets -when infected with bacteria less feeding and immune crickets chose low fat is head and avoided high fat or abdomen thorax and legs
