Improving the Adaptability of Animals by Selection - Genetics and the Behavior of Domestic Animals - page 303

SOCIAL BEHAVIOR
The influence of selection for social reinstatement behavior on the tendency
to approach flockmates has been measured in various ways. Launay et al.
(1991) compared approach tendencies toward paired goal boxes which either
were empty or contained a group of conspecific (flockmate) chicks. High SR
line chicks spent more time close to goal boxes containing conspecifics than
low SR line chicks ( Figure 8.15 ). Mills et al. (1992) and Francois and Mills
(1996) compared interindividual distances in mixed or same-line pairs of
high SR and low SR line chicks in open-field tests. At 1 and 3 weeks of age,
interindividual distances were greatest in the low SR/low SR pairs, interme-
diate in high SR/low SR line pairs, and lowest in the high SR/high SR pairs,
intermediate in high SR/low SR line pairs, and lowest in the high SR/high
SR line pairs ( Figure 8.16 ). In other words, low social reinstatement chicks
stand away from each other and high social reinstatement chicks group
together. At 6 weeks of age,

there were no significant differences in

(a) (b)

200 100

150 75

100 50

50 25

0 0

FIGURE 8.15 Proximity indices in lines of Japanese quail selected for high or low level of
social reinstatement behavior over five generations. ( ' ) HSR, ( ) CSR, ( & ) LSR.

300
250
200
150

100
50
0

Week 1 Week 3 Week 6

FIGURE 8.16 Interindividual distances in the open field between pairs of 1-, 3-, and 6-week-

old quail from lines selected for high or low level of social reinstatement behavior over 18 gen-
erations. ( ' ) HSR/HSR, ( ) HSR/LSR, ( & ) LSR/LSR.