534 Invasive Stink Bugs and Related Species (Pentatomoidea)
PhPR of adult diapause induction is most clear at high temperatures (27 to 30°C) and completely sup-
pressed by low temperature, whereas photoperiodic control of body color in nymphs manifested itself
under all tested conditions (Volkovich and Saulich 1995). Taking into consideration that incidence of
dark-colored nymphs is much higher under short-day and low-temperature conditions (Figure 11.20),
it might be speculated that appearance of pigmented nymphs is related to thermoregulation and takes
place in colder periods of late spring (and early autumn in the regions where two generations can be
produced per year; see Chapter 12). It is well documented that melanization of insect cuticle in the
spring and autumn (when days are short) enhances absorption of solar insulation and, as a result, the
body temperature can be up to 10 to 15°C higher than the air temperature (Hoffmann 1974, Tauber et
al. 1986). Lighter color, due to low pigmentation, helps avoid overheating during the hottest days in
mid-summer.
An interesting and complex case of seasonal body color change was reported in the parent bug, Sinopla
perpunctatus (Faúndez and Osorio 2010). In southern Chile (53°S), this species has a univoltine seasonal
cycle. Young adults of both sexes are dark green when they emerge in late summer as are the leaves on
ABCDEFGHFIGURE 11.17 (See color insert.) Diapause-associated body color changes in the southern green stink bug, Nezara
viridula, reared under laboratory or quasi-natural outdoor conditions. Laboratory rearing in Kyoto (Japan): reproductive
(i.e., nondiapause) green adult (A). Adults of the intermediate body color grade (B, C left). Diapausing russet (brown) adults
(C right, D). Outdoor rearing in Kyoto: mostly intermediate colored and russet overwintering adults at the early stages of
diapause (November–December; E, F); adults of different body color grades at the later stage of diapause (March; G);
diapause termination, body color change and beginning of postdiapause reproduction (April; H). (From D. L. Musolin,
Physiological Entomology 37: 309–322, 2012, with permission.)