Biology Reference
In-Depth Information
(a)
(b)
(c)
7
0.15
0.15
5
0.10
0.10
3
0.05
0.05
1
0.00
0.00
S.RT
S.RA
NS.RT
Pairs
NS.RA
Littermate
Littermate
Full-
sisters
Half-
sisters
Full-
sisters
Half-
sisters
Fig. 11.5
Kin recognition in Belding's ground squirrels. (a) Laboratory experiments: mean number (
±
1 SE)
of agonistic encounters between pairs of yearling Belding's ground squirrels in arena tests. Non-siblings reared
together (NS.RT) are no more aggressive than siblings reared together (S.RT). However, non-siblings reared apart
(NS.RA) are more aggressive than siblings reared apart (S.RA). (b) and (c) Field observations: aggression and
cooperation among yearling females which were full or half-sisters (genetic relatedness determined by blood
proteins). Full sisters are less aggressive to one another (b), and assist each other more (c). From Holmes and
Sherman (1982). Photo of a calling female © George D. Lepp.
(1982) show that sibling recognition in ground squirrels (
U. beldingi
) is also in part
based on association in the natal nest. They captured pregnant females and used their
pups to create four kinds of experimental rearing groups: siblings reared by one mother
(their own or a foster mother), siblings reared apart by different mothers, non-siblings
reared as a single litter and non-siblings reared apart. When they were older, animals
from the four groups were placed in pairs in arenas and their interactions were observed.
Holmes and Sherman found that regardless of true genetic relatedness animals that
were reared together rarely fought. Figure 11.5 shows that unrelated individuals reared
