Green et al., 2016 (Cooperative breeding birds)

Question 1

Inclusive fitness predicts that cooperative investment should correlate … with the … of helpers to the recipients of their care

Answer 1

positively, relatedness

Question 2

This study compares helper … in … cooperatively breeding bird species

Answer 2

investment, 36

Question 3

Show that species-specific helper contributions to cooperative care increase as the mean … between helpers and recipients increases

Answer 3

relatedness

Question 4

Helper contributions are also related to the … … of helpers

Answer 4

sex ratio

Question 5

Neither … … nor the proportion of nests with … influence helper effort

Answer 5

group size, helpers

Question 6

Consistent with … rule: indicating key role for … … in the evolution of cooperative investment in social birds

Answer 6

Hamilton’s, kin selection

Question 7

Interspecific studies show that alloparental care by helpers is more likely to evolve in species with low ….

Answer 7

promiscuity

Question 8

Mean provisioning rate of helpers was expressed as a..

Answer 8

proportion of the provisioning rate of the parents

Question 9

Mean kinship (r) of helpers to brood was determined fro…

Answer 9

published pedigree information, supplemented where possible by relatedness estimates from genetic analyses

Question 10

What were the three variables, other than kinship, that were investigated for their influence on helper effort?

Answer 10

• reproductive constraint, using the proportion of breeding pairs in study populations that had helpers as a measure of this (if constraints are lower, helpers more likely to go and breed independently
• The mean group size (breeders+helpers) of each species, excluding breeders without any helpers and any non-helping group members (see next card for why)
• average helper sex ratio, as the care of helpers could vary consistently in relation to their sex.

Summary: kinship, helper sex ratio, group size and percentage of nests with helpers

Question 11

In cooperative breeding systems, breeders often benefit from reduced reproductive costs if they reduce their own … rate when ….

Answer 11

provisioning, helped

Question 12

Helper effort approached 100% (that is, very similar to that of breeders) when r was close to ….

Answer 12

0.5

Question 13

only … and … had an effect on helper effort

Answer 13

kinship, sex ratio (helper effort was found to decrease significantly with the proportion of helpers that were male)

• in species with more female-biased helper sex ratios, helpers of both sexes work harder relative to parental effort

Question 14

What could explain the sex-ratio effect on helper effort?

Answer 14

Increased kinship to brood arising from strong ecological constraints and reduced female dispersal provides a potential explanation for the increased provisioning effort of helpers in species with more female-biased helper sex ratios

Question 15

Finding provides an explanation for at least some of the unexplained variation in helper investment across ….

Answer 15

species

Question 16

Does not necessarily imply that that …-… gains are the only fitness benefits derived by helpers (other possibilities include increased survivorship or inheritance of the breeding territory) - but do reaffirm the central role of relatedness in the expression of cooperative behaviours

Answer 16

kin-selected