32 S. Singh
(except body size:wing length) compared to be-
tween population differences (Table 4 ).
Correlations Between Traits Based on iso-
female lines data, within population analyses
for correlation of mating related traits (mat-
ing latency, copulation duration and fecundity)
with body melanisation are shown in Fig. 3 and
Table 4. There are significant correlations for
ML ( r =− 0.90); CD ( r = 0.81), and fecundity
( r = 0.95) with assorted dark and light flies on the
basis of body melanisation (Fig. 3 ). Small- and
large-sized flies assorted on the basis of body
size (wing length) show lack of correlations with
ML, CD and fecundity ( r = ns). Thus, within
population variation in body size show a lack
of correlation with body melanisation as well as
mating related traits (Fig. 3 ). This analysis fur-
ther supports correlated changes in body mela-
nisation (not body size) and mating related traits
in D. immigrans.Selection: Supporting Evidence Results of
laboratory selected dark (DSS) and light (LSS)
body color strains are illustrated as bars (Fig. 4 ).
For body melanisation, darker selected strain
showed about 1.6-fold increase while lighter
strain exhibited ~ 2 fold decrease in compari-
son to control population after 18 generations
of selection (Fig. 4 ). The selected strains variedMating Latency ( min )Number of Isofemale lines
024681012145101520Large
Mean = 14.1 8
Mean = 13.5 Small 0 S.D. = 2.21
S.D. = 2.10cWing length (mm)Number of Isofemale lines
024681012143.03.2 3.43.6 3.84.0 4.24.4Small
Mean = 3.58
SD = 0.08Large
Mean = 4.13
SD = 0.12bdCopulation duration ( min )
Number of Isofemale lines
0246810121430 40 50 60 70Large
Mean = 54.30
S.D. = 1.46Small
Mean = 55.12
S.D. = 1.37Melanisation ( % )Number of Isofemale lines
0246810121430 40 50 60 70Large
Mean = 55.60
S.D. = 3.43
Small
Mean = 54.70
S.D. = 3.37a
Fig. 1 Isofemales of D. immigrans similar in body size (a), but varying in body melanization ( dark vs. light) (b), differ
significantly in mating latency (c), and copulation duration (d)