DYNAMICS OF FIELD POPULATION OF PINE LOOPER
265
diameter will be correlated with larval density, a:3 illustrated in Fig. 24
for both males and females. In the former the effect of density is much
less pronounced than in the latter, which is in accordance with the
results of the experiment described earlier (see p. 251). As in the larvae,
the growth inhibiting effect of density is particularly evident in the
low range, and again appears to be slight or absent at densities higher
than 12 larvae/m2 (cf. Figs. 21 and 22).
3. Adult Fecundity
It was shown (Fig. 14) that within a generation, fecundity is highly
correlated with pupal diameter (means indicated by crosslets). As said
L L -
4 3 -
\ 0 5 3
MALES
W
I
4
.58
L.7L61
FEMALES
. 5 j \
a56
m51
i
8
12
16
20
U
28
LARVAL DENSITY (NUMBERS PER S Q H.)
Fro. 24. Correlation between larval density and pupal size. The numerals refer to yeam
(autumn). See Table XXI, columns 2, 7, and 8.