Seasonal Cycles of Pentatomoidea 591
low temperatures, it can become a serious nuisance pest (Hoebeke and Carter 2003, Nielsen and Hamilton
2009, Nielsen et al. 2011, Inkley 2012, Cambridge 2015; see Chapter 4).
In different parts of its native range in Asia, Halyomorpha halys produces one or two generations
per year (Lee et al. 2013). In laboratory experiments with the bugs from the Nagano population (Japan;
36.5°N), Yanagi and Hagihara (1980) have demonstrated that induction of the facultative winter adult
diapause is controlled by day length. At 25°C under a day length of 14 hours 45 minutes or shorter, adults
entered winter diapause, whereas all adults were reproductive if the day was 15 hours 30 minutes or longer
(Figure 12.20).
When the nymphs were reared to adults and then maintained under semi-natural outdoor conditions in
Nagano, it was demonstrated that adults that had emerged after July 15–25 did not reproduce but began
to enter facultative winter adult diapause (Figure 12.21). At this time of the year, natural day length is
similar to the critical photoperiod determined under laboratory conditions plus 30 minutes that usually
are reserved for the civil twilights because, as had been shown experimentally, many insect species
recognize the civil twilights as a part of photophase (i.e., a light part of the day cycle; Goryshin and
Geispitz 1975).
Thus, even early studies of the seasonal development of Halyomorpha halys within its natural range
clearly demonstrated that this species has the day-length-controlled facultative winter adult diapause,
which allows it to produce different number of annual generations in different parts of its native range
depending on the local temperature or other environmental conditions. Later, it also was demonstrated
100500
14:00 14:30 15:00 15:30 16:00
Photoperiod, hIncidence of diapause,%FIGURE 12.20 Effect of photoperiod on induction of the facultative winter adult diapause in the brown marmorated stink
bug, Halyomorpha halys, from Nagano (36.5°N), Japan. Nymphs were reared to adults and then maintained at 25°C under
constant photoperiodic conditions (indicated under the horizontal axis). (From T. Yanagi and Y. Hagihara, Shokubutsu-
Boeki [Plant Protection] 34: 315–321, 1980, with permission.)
100
15:10
15:00
14:50
14:40501 20
15 30510152025315101520 30
June July AugustIncidence of diapause,%FIGURE 12.21 Diapause induction in the brown marmorated stink bug, Halyomorpha halys, under natural day length
in Nagano (36.5°N), Japan. Curve 1 is natural day length in Nagano + 30 minutes of the civil twilight (inserted vertical
axis); curve 2 is incidence of facultative winter adult diapause (black symbols are at outdoor temperature; white symbols
are at room temperature). (From T. Yanagi and Y. Hagihara, Shokubutsu-Boeki [Plant Protection] 34: 315–321, 1980, with
permission.)