11-family conflict Flashcards
what is SS characterised by and what can it result in in extreme cases?
sexual conflict
infanticide
what is langurs + lions example of infanticide? (3)
- matrilineal societies with 1 reproductive M
- M taking over group has limited time to reproduce
- effective to kill rival offspring so can reproduce with F as she comes into oestrus sooner
describe sex role reversal + sexual conflict in wattled jacana?
polyandrous F with 2+ males
new F kills original broods + chicks start afresh with original M
what are 3 examples of conflict over reproduction?
- co-breeding
- breeding vs helping
- inbreeding
what are joint nesting F usually?
close relatives
what is the co-breeding example for acorn woodpeckers in 103 nests? (6)
- F cobreeders
- multiple M + F breeders - eggs laid in joint clutch
- 86% F first order kin
- 38% eggs laid in joint nests destroyed
- reproductive conflict + suppression by cobreedrs
why are eggs laid in joint nests destroyed? (3)
- F destroying eggs of other F before incubation
- F cant distinguish between own eggs and other F
- 10% eggs laid by joint nesting F are runt eggs laid early when high risk egg destruction
in terms of breeding vs helping what is the meerkat example? (3)
- 3-50 dominant F + M subordinate F and subordinate M
- negative effect of subordinate reproduction on fitness of dominants pups results in reproductive suppression by dominants of subordinate reproduction
- reproductive suppression by dominants + subordinates
in terms of breeding vs helping for meerkats what often fails?
more subordinate pregnancies and litters fail
how is subordinate meerkat reproduction costly? (4)
- if dom breeds alone without sub, pups weigh more (vital for survival)
- pregnant dominants evict subordinates
- allowed back into group when sub pups born
- more likely evicted if less related
what % chance is there of sub meerkats being evicted if they are daughter/sister vs grandmother/niece?
25%
over twice as high
what can some eusocial insect species workers do event though they don’t mate?
retain functional ovaries to produce sons as M develop from unfertilised eggs produced
in hymenoptera how is a F worker related to…
a) son
b) worker/sister
c) nephew
- so what should workers do?
a) 0.5
b) 0.75
c) 0.375 (0.75/2)
- lay eggs and produce sons
what is the relatedness for a sister-sister diagram when the queen mates once?
via mother: 0.5X0.5=0.25
via father: 1X0.5=0.5
r= 0.75
what is the relatedness for a sister-sister diagram when the queen mates multiple times?
- what does this mean? (2)
via mother: 0.5X0.5=0.25 via multiple possible fathers: =0 r=0.25 - less chance of having same father - this is why monogamy is importance in evo of eusociality
when queen mates multiple times what do queens prefer (1) and what do workers prefer (2)?
- queens prefer sons (r=0.5) to grandsons (r=0.25)
- workers prefer sons (r=0.5) to brothers/queens sons (r=0.25)
- workers prefer brothers (0.25) to nephews (r=0.125)
what is worker policing?
workers prevent other workers from reproducing
what is ratneiks + visschers example of worker policing in hymenoptera? (4)
- worker laid M eggs eaten within 7-8 hours
- queen laid M eggs not targeted
- workers eat introduced eggs from other workers more than eggs from queens
- can discriminate between eggs laid by workers and laid by queens
what is foster + ratneiks 2000 example of worker policing in wasps? (3)
- worker reproduction depends on mating frequency
- high worker r means lots of worker reproduction
- policing of egg laying by workers facultative behaviour depending on mating frequency
what did Wenseleers + Ratnieks 2006 find about worker policing?
occurs interspecifically and also serves to enforce altruism
what did Loope 2015 discover about queen mating and worker relatedness?
- mates once: workers more closely related to nephews (0.375) than brothers (0.125)
- mates multiple times: workers more closely related to brothers (0.25) than nephews (0.125)
what should occur in monogamous colonies when a colony switches from producing workers to producing sexual?
workers should kill queen
what causes certain colonies to be queenless?
where workers kill queen when high worker relatedness
in emlen and wrege study on white fronted bee eater harassment what is the harassment and who do breeders harass?
chasing, interference in courtship + blocking nest access/egg removal
in emlen and wrege study on white fronted bee eater what % of victims became helpers at the nest of the harasser?
34%
in emlen and wrege study on white fronted bee eater if the breeder + helper are close kin how many young does breeding alone produce and how many young does each helper add?
0.51 young
adds 0.47 young
in emlen and wrege study on white fronted bee eater if breeder + helper are close kin what is the difference in the breeder and the helpers perspective?
helpers: helping has about the same pay off as breeding does, pay off similar if breeders closely related
breeders: helpers breeding alone produces 0.26 young for the breeder which isn’t as good as 0.47 if helper could breed
in emlen and wrege study on white fronted bee eater when do breeders gain more inclusive fitness?
if they help kin rather than breeding independently
in emlen and wrege study on white fronted bee eater what are the % of recruitment of victims as helps at each of these relatedness:
a) r=0.5
b) r=0.25
c) r=0.125
a) 75%
b) 35%
c) 0%
what can also result in conflict between breeders + helpers?
the risk of inbreeding
what is the risk of inbreeding/incest in Koenig 1998 study of acorn woodpeckers?
- potential for incest if breeder dies + replaced by helper related to remaining breeder
- conflict over who reproduces in the group likely after death of one parent between remaining parent + opposite sex offspring
- 5% of 75 cases of potential breeding resulted in incest
how is incest avoided in acorn woodpeckers? (4)
- power struggle over who remains in territory, 50% of cases resolved in a month
- 10% these take a year
- max take 3.8 years
- helpers evicted from territory
in acorn woodpeckers what % of helpers + breeders left when F breeder + helper sons?
helper left: 64%
breeder left: 27%
in acorn woodpeckers what % of helpers + breeders left when M breeder + helper daughters?
helper left: 91%
breeder left: 2%
what does resolution of family conflict depend on?
sex of protagonists but may be substantial costs in terms of reproductive output?
CHECK APS 209 DECK 6
SS
what does family conflict involve conflict over?
resources
what does Trivers 1974 parent offspring conflict model suggest parents and offspring will disagree over?
optimal investment of parental care when parents are investing more than offspring
give 5 points about Trivers 1974 parent offspring conflict model
- more investment in offspring means more likely to survive but is curve of diminishing returns
- investment is costly
- offspring cost is cost/2
- parents should aim for max inclusive fitness
- optimal investment for parent less than optimum for offspring
what does sibling rivalry involve conflict over, what does it often result in + give 2 examples
- limited resources
- siblicide + cannibalism
- sand tiger shark: multiple eggs fertilised internally but only 1 offspring as largest foetus eats siblings
- spadefoot toad: cannibal morphs
what is Frank et al 1991 example of hyena sibling rivalry? (4)
- twin pups unsupervised in burrows + fight often resulting in one dying
- rivalry more intense in same sex twins
- would expect 50% same sex twins but actually 15%
- same sex siblings are future reproductive competitors
describe the black eagle example for sibling rivalry (3)
- in 199/200 nests 2 eggs hatch 3 days apart, only 1 survives
- canism
- older chicks attack younger siblings when they hatch
describe the blue footed boobie example for sibling rivalry (3)
- 2 chicks hatch asynchronously
- larger occasionally pecks smaller
- if food scarce, violence escalates until younger chick killed or evicted
describe the great white egret example for sibling rivalry (4)
- 3-4 young hatch at 1-2 day intervals producing hierarchy in size
- intrabrood aggression: older chicks get more food + grow quicker
- smaller chicks evicted from nest
- 1/3 nests attacks end in siblicide
what are the 5 main characteristics of siblicide?
> resource competition > monopolise resources > spatial conflict > weaponry > competitive disparities
what is the white winged chough example of resource competition (Boland 1997)?
- often chicks die of starvation
- less competition in siblings in nests with more food + higher survival
how can resources be monopolised?
larger chicks get more food faster from parents
how are competitive disparities under parental control?
set up by parents as some offspring are older than others
list 2 main reasons for why siblicide occurs
- insurance
- parental optimism
what is insurance? + what species?
only enough resources for one chick so the second is produced as insurance against the first not surviving
- black eagle
what is parental optimism?
large clutch produced where in good conditions all survive but in poor conditions sibling rivalry reduces brood size
give an example of parental optimism
cattle egrets (mock + ploger 1987)
- brood hierarchy arises from parental strategy to engineer optimal hatching asynchrony
- time eggs hatch is manipulated
explain sibling rivalry in humans, as studied by Rickard et al 2007 (5)
- sibling rivalry may have subtler effects than siblicide
- could occur in siblings from different broods
- may affect fitness
- sons more costly to produce
- if elder sibling F then higher lifetime reproductive success
what is the parent offspring conflict in the american coot (lyon et al 1994)? (5)
- parental care essential for survival as 50% chicks starve
- parents control who does + doesn’t get food
- orange feathered chicks signal to parents offspring quality
- those painted orange rather than blacks were fed more, grew faster + survived better
- parental favoritism
what is parental favouritism?
only a fraction of the brood survives so offspring compete for parental care using ornaments such as signals
a) in humans what are foetal genes selected to maximise?
b) what are maternal genes selected to maximise?
c) what happens as a result?
a) transfer of nutrients to foetus
b) not to exceed maternal optimal
c) genetic conflict between mother + foetus over control of nutrient supply to foetus
during implantation what do fetal cells do and what 3 things does this result in?
modify endometrial arteries into low resistance non constricting vessels
- foetus gains direct access to maternal blood
- blood flow to placenta not under local control
- placenta can release hormone into mothers blood
what 2 things can foetal manipulation result in and explain each
- GESTATIONAL DIABETES: placenta release human lactogen to maintain blood glucose levels, mother increases insulin in response, diabetes occurs in mother if inadequate response
- PRE-ECLAMPSIA: foetus enhances blood + nutrient flow to placenta by increasing maternal blood pressure, if too high then both lives threatened and risk of hemorrhage in mother
describe findings from lawson + mace 2011 study on parental investment + child development (4)
- more offspring = less parental care to share
- more offspring = more economic hardship
- more offspring = -ve effect on school attainment
- family conflict occurs after birth where fitness measures are negatively related to family size
what are families characterised by?
conflict + coop
