374 Invasive Stink Bugs and Related Species (Pentatomoidea)
preparation in autumn, and/or during the overwintering period, as suggested for some beetles (Fuzeau-
Braesch 1985, De Jong et al. 1996, Gross et al. 2004).
Laboratory experiments with the green morph show that the adult body color change is under pho-
toperiodic control (Figure 7.9). This also is the case in other color morphs of the species, as shown
in numerous outdoor rearing experiments (Dmitry L. Musolin, unpublished data). For the following
experiments, we used only adults that emerged as the green morph. Under long-day conditions, they
remain green their entire life (see Figure 7.1C); but under short-day conditions, virtually all adults
gradually start to change body color to intermediate and then russet brown after 12 days (median) at
25°C or 24 days at 20°C (Figure 7.1D; Musolin and Numata 2003a). Under near-critical photoperiodic
conditions, adults of the intermediate color always are present and some adults change color more
than once (e.g., from green to russet and then back to intermediate or green). The dynamics of color
change are similar in both sexes and comparable proportions of adults of both sexes reach deep rus-
set color. Unexpectedly, a lower temperature (20°C) fails to accelerate the change of the body color to
the overwintering coloration, whereas the short-day length does: the shorter the photophase, the faster
the rate of color change (Figure 7.9; Musolin and Numata 2003a). These observations provide strong
Males
30Females20
10
030
20
10
0(^3030)
(^3030)
(^3030)
20
(^2020)
20
20 20
20
10
10 10
(^1010)
0
20
10
0
0 0
0
(^00)
0
0 0
0 0
100 100
100 100
50 50
50 50
40 60 40 60
Days after adult emergence Photoperiod, h
L:D 10:14
L:D 12:12
L:D 13:11
L:D 14:10
L:D 15:9
L:D 16:8
Numb
er of ins
ects
FIGURE 7.9 Effect of day length on adult body color in Nezara viridula at 25°C. White, gray, and black sections of the
bars indicate the proportion of females and males with green, intermediately colored, and russet bodies, respectively.
(From D. L. Musolin and H. Numata, Physiological Entomology 28: 65–74, 2003a, with permission.)