Reading 6.2 Wright 2009 Flashcards
1
Q
Hypotheses tested
A
- 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.
2
Q
The methods
A
- 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
3
Q
When did the study take place?
A
2004-2006
4
Q
How many bell miner colonies were observed?
A
Two - Australia
5
Q
When was help provisioning data collected?
A
Day 6 onwards when help is at a maximum
6
Q
How many nests were observed?
A
27 each with two nestlings
7
Q
How was nestling begging recorded?
A
- Using a sound recorder
8
Q
Results
A
- 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.
9
Q
What the results mean in relation to the hypotheses being tested
A
- Good example for kin selected helping in a cooperative bird
- Less female helpers could be attributed to the young disperal of female
10
Q
Group augmentation in regard to the study
A
- “extreme sex - biased dispersal should produce large sex differences in the future fitness benefits accrued from increasing number of offspring recruits”
11
Q
What does the study support?
A
Facultative adjustment of bell miner in nest visit rates
12
Q
Could non- related helpers be explained by direct fitness benefits?
A
No
13
Q
Behavioural rules
A
- All individuals used same behavioural rules to regulate provisioning investment despite the investors receiving varying fitness benefits
