SR11: Green+ Hatchwell 2016- helper effort variation in cooperatively breeding birds Flashcards Preview

APS 209: Animal behaviour > SR11: Green+ Hatchwell 2016- helper effort variation in cooperatively breeding birds > Flashcards

Flashcards in SR11: Green+ Hatchwell 2016- helper effort variation in cooperatively breeding birds Deck (32)
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1
Q

what does the inclusive fitness theory predict cooperative investment should positively correlate with?

A

relatedness of helpers to recipients of their care

2
Q

what was the comparative analysis of?

A

helper investment in 36 cooperatively breeding bird species

3
Q

what increases as mean relatedness between helpers and recipients increases

A

species specific helper contributions

4
Q

what fact did the study support?

A

that variation in helping behaviour in cooperatively breeding birds is consistent with hamilton’s rule

5
Q

in vertebrate cooperative systems what are social groups mainly comprised of?

A

close relatives

6
Q

what is more likely to evolve in species with low promiscuity?

A

caring for others offspring

7
Q

what does hamilton’s rule predict?

A

conditions under which kin selected cooperation should evolve with investment in cooperation greater as relatedness between actor and recipient increases

8
Q

when are potential helpers more likely to help?

A

when recipients close kin

9
Q

when caring for young what is the trade off?

A

between fitness gained from current investment against costs of investment for future fitness gain

10
Q

what does comparing helper effort across species show?

A

that helper investment increases with kinship to the brood

11
Q

what was the mean provisioning rate of helpers expressed as a proportion of?

A

provisioning rate of parents

12
Q

when should helper investment be high?

A

when probability of future independent breeding is low

13
Q

if most individuals in a population can breed then what does this mean?

A

low constraints on reproduction and few pairs have helpers

14
Q

what should carers adjust their care according to

A

the number of carers at a nest

15
Q

typically what sex are the helpers?

A

male due to females dispersing and reproducing outside their natal group so the sex ratio is often male biased

16
Q

how many species in how many families was data collected from?

A

36 species in 23 families

17
Q

in all species what did care provided by helper increase with?

A

kinship to the brood

18
Q

what % did helper effort approach when r was close to 0.5? and what does this support?

A

100%

supports inclusive fitness theory

19
Q

when should kin discrimination only be selected for?

A

when risk to caring for non kin

20
Q

what may happen if costs are low and indirect benefits are high?

A

lots of helpers may care for non kin

21
Q

when did helper effort decrease?

A

with proportion of male helpers

22
Q

when do both sexes work harder relative to parental effort?

A

when more female biased helper sex ratios?

23
Q

if females remain in their natal territory what does it mean?

A

higher relatedness in groups which may select for more provisioning effort by helpers

24
Q

what does helper contributions to brood care increase with?

A

relatedness of helpers to recipients

25
Q

what is a direct fitness benefit that may arise?

A

inheritance of the breeding territory

26
Q

what does the optimal strategy for investment depend on?

A

investment of others in the same brood

27
Q

how does it provide evidence for hamiltons rule?

A

close relatives provide more care

28
Q

in cooperatively breeding species in some cases what do helpers assume most?

A

the responsibility for brood care

29
Q

what was it testing?

A

if variation in helper contribution is predicted by inclusive fitness theory

30
Q

what will happen when constraints on successful independent reproduction are high and an example

A

most pairs will have helpers such as the white winged chough

31
Q

what is the result for the females when helpers are typically male

A

higher probability of dispersing and of independent reproduction outside the natal group

32
Q

what findings from other studies does it support?

A

that there is consistent discrimination in favour of kin by helpers