QUESTION 1: Emlen and Wrege (1988) reported that in 88.5% of cases of white-fronted bee-eaters ing at the nest, the recipients (le, parents of the

QUESTION 1:
Emlen and Wrege (1988) reported that in 88.5% of cases of white-fronted bee-eaters ing at the nest, the recipients
(le, parents of the nestlings) were kin to the er. Moreover, in 44.8%% of all cases, the ers were offspring of the
recipients, so they were ing their parents rear full siblings. In somewhat fewer cases (19.0%), the ers were
ing one parent and a step-parent to rear half-siblings. In 10.3% of cases, a parent was ing a son and daughter-
In-law. Why are these data not enough to show that bee-eaters preferentially direct their ald to the closest genetic
relatives? other information did Emlen and Wrege need in order to determine whether these birds actually prefer
to kin more than non-kin members of the clan? Are the findings of Emlen and Wrege (1988) consistent with
Hamilton’s Rule? Explain why, or why not.
1. Because of lack of attention to the availability of potential recipients from varying kinship classes. When
giving the birds a choice for the recipient of their and contrasting the distribution of given vs that
expected if recipients had been chosen at random. To the same effect, the coefficient of relatedness needed to
be analyzed. In both Instances, It was once again found that bee-eaters preferentially direct their based on
levels of kinship.
2. Clan membership status needed to be taken into account. The mates who had left their clan to join their present
one aren’t closely genetically related to those in their new clan. Natal members of clans were seen to be far
more likely to become ers, coinciding with the kinship prediction. Equally, instances outside of the norm
needed to be taken Into account. When analyzing the instances where individuals decided to In another
clan and the instances where er aided seemingly unrelated recipients, the same findings regarding the
Importance of kinship were found.
3. Hamilton’s rule suggests that more Individuals should become ers when the fitness benefits towards the
recipient (B) are large, when the cost to the er (C) is small, and when the coefficient of relatedness (r)
between the er and recipient is large. In the study, the benefit variable (B) was analyzed and they found
that nestlings greatly benefit from increasing numbers of ers, with it rarely reaching a point of diminishing
returns. Similarly, the cost variable (C) was analyzed looking at both presumed costs: energy cost of ing
and deferring their own reproduction. When it came to the first cost, it was found that individuals that would
require more effort to (higher cost) were significantly less likely to become ers compared with those
that ing would require less effort (lower cost). As for the second cost, it was assumed that the potential cos
would be higher for paired birds, as they would have a greater chance of becoming breeders. When analyzed,
was seen that paired birds (higher cost) were significantly less likely to become ers than single birds
(lower cost). Finally, when analyzing the coefficient of relatedness (n) It was expected that the likelihood of a
bird becoming a er decreased with decreasing n value. This was seen to be the case in low cost birds, but in
high cost birds there seemed to be a lower threshold, implying that for these high cost birds the fitness benefit
of ing rarely outweighed the costs when the relatedness of the recipient was below 0.25. Taking all of this
Into account, it can be seen that the findings of the study are consistent with Hamilton’s Rule.