special reading - cooperative breeding - 1 - helping effort in bell miners Flashcards Preview

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Flashcards in special reading - cooperative breeding - 1 - helping effort in bell miners Deck (6)
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1

what is the aim of this paper?

distinguish between the only remaining hypotheses, kin selection and group augmentation, for the evolution of helping-at-the-nest in a cooperative bird
- predict an incremental increase in helping effort with genetic relatedness

2

what are they exploring?

- explores in detail within- and between-individual variation in nest visit rates, load sizes and prey types delivered by parents and helpers according to sex and genetic relatedness in bell miners
- also examine visit-by-visit responses of breeders and helpers to nestling begging signals of brood need

3

what were the results?

- proved kin selected helping – however no evidence that bell miners were more likely to help at the nests of relatives
- Bell miner helpers seemed to attend hungry broods located within their coterie as required, irrespective of helper sex or relatedness to the brood
- no sex differences were detectable in any aspect of helping, and even non-relatives provided substantial aid

4

what do the results mean in relation to the hypotheses being tested?

- comprehensive test for both direct and indirect fitness effects on helping- showed no direct fitness benefits for some just that the visiting rates were strongly effected by the begging rates of the chick
- suggested within coterie relatedness could explain the apparent indirect effects

5

what do the results mean in relation to the study of animal behaviour in general?

- Helping behaviour in bell miners appears consistent with adaptive cooperative investment in the brood, and kin-selected care by relatives

6

methods

- studied two different bell minor populations in Australis
- molecular analyses of relatedness between individuals
- identified parent birds
- measured provisioning efforts between 6-12 days
- visual score of begging intensity

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