Reading 6.2 Wright 2009

Question 1

Hypotheses tested

Answer 1

• to distinguish between kin selection and group augmentation, for the evolution of helping-at-the-nest in a cooperative bird
  • test for both direct and indirect fitness effects on helping, as well as an exploration of the behavioural rules of thumb used to regulate individual helping effort within each nest.

Question 2

The methods

Answer 2

• 2004 -2006 at two different bell miner colonies in australia
  • Birds relationships were calculated from blood samples
  • Provisioning data was collected from day 6 onwards when helping is at a maximum
  • 27 nests observed all containing two nestlings
  • Average of 8.5 hours per nest

Question 3

When did the study take place?

Answer 3

2004-2006

Question 4

How many bell miner colonies were observed?

Answer 4

Two - Australia

Question 5

When was help provisioning data collected?

Answer 5

Day 6 onwards when help is at a maximum

Question 6

How many nests were observed?

Answer 6

27 each with two nestlings

Question 7

How was nestling begging recorded?

Answer 7

• Using a sound recorder

Question 8

Results

Answer 8

• Most non-breeding individuals were seen attending at least one nest

Provisioning effort

- Effect of relatedness on visit rates, load size and biomass but not for lerp delivered.

Question 9

What the results mean in relation to the hypotheses being tested

Answer 9

• Good example for kin selected helping in a cooperative bird
  • Less female helpers could be attributed to the young disperal of female

Question 10

Group augmentation in regard to the study

Answer 10

• “extreme sex - biased dispersal should produce large sex differences in the future fitness benefits accrued from increasing number of offspring recruits”

Question 11

What does the study support?

Answer 11

Facultative adjustment of bell miner in nest visit rates

Question 12

Could non- related helpers be explained by direct fitness benefits?

Answer 12

No

Question 13

Behavioural rules

Answer 13

• All individuals used same behavioural rules to regulate provisioning investment despite the investors receiving varying fitness benefits