514 Invasive Stink Bugs and Related Species (Pentatomoidea)
11.3.2.1 Effect of Temperature on the Photoperiodic Response
Curve during Induction of Winter Diapause
Low temperature usually promotes induction of winter diapause. In some species, this effect is most
evident around the critical photoperiod, but, in others, it is most evident under short-day or long-day con-
ditions. High temperatures (such as 30 to 32°C) can strongly suppress the effect of day length and even
completely prevent induction of winter diapause in some species. On the other hand, low temperatures
(usually 15°C or below) enhance the tendency towards winter diapause and all individuals enter diapause
irrespective of the preceding day length.
Degree of sensitivity of the critical photoperiod to temperature varies in different species. It is even possible
to organize different species on the basis of temperature sensitivity of their PhPRs of diapause induction from
a strong dependence of the critical photoperiod on temperature to a temperature-stable PhPR with the critical
photoperiod almost insensitive to temperature (Saulich and Volkovich 2004). Based on the data from many
insect species, it has been shown that within a range of 20 to 27°C, a temperature shift of 5°C can cause a shift
of critical photoperiod of approximately 1 hour (Danilevsky 1961). In other species, including Podisus macu-
liventris, a critical photoperiod of diapause induction basically remains stable within a temperature range of
17.5 to 25.5°C, even though a proportion of diapausing individuals generally decreases under short-day condi-
tions and PhPR can be strongly suppressed under high temperatures (Figure 11.6; Goryshin et al. 1988a).
The results of experimental studies of winter adult diapause in the pentatomid Scotinophara lurida demon-
strate that temperature can affect the quantitative PhPR in a similar way: the higher the temperature, the more
diapause is suppressed even under typically diapause-inducing conditions (Figure 11.3; Cho et al. 2008).
The main ecological function of temperature in insect diapause onset is the optimal timing of dia-
pause induction during the season. In warm years, winter diapause induction shifts to later dates due
to the critical photoperiod decreasing under the action of high temperatures whereas in cold years, an
earlier induction of winter diapause takes place. In general, an increase in temperature suppresses the
tendency to enter winter diapause, whereas a drop in temperature facilitates induction of winter diapause.
However, the signal function of temperature cannot always be distinguished (or separated) from the
direct suppression of activity by low temperatures. In many cases, especially in southern species that
overwinter as adults, the absence of oviposition in the field might often be caused by the direct suppres-
sion of maturation and/or oviposition by the low ambient temperature rather than by induction of winter
adult diapause (Saulich and Musolin 2009).
1008060Incidence of diapause,%40200
812168 12 16 812161014
Photoperiod, h17.5°C 20.0°C 25.5°C 27.5°CFIGURE 11.6 Effect of constant temperature on the photoperiodic response of winter adult diapause induction in
females of the spined soldier bug, Podisus maculiventris. The laboratory culture originated from Missouri, the United
States of America (about 38°N). Nymphs were reared to adults and then maintained under constant experimental condi-
tions. Vertical lines are ranges of results in different replicates of the experiments. (From N. I. Goryshin, T. A. Volkovich,
A. Kh. Saulich, M. Vagner, and I. A. Borisenko, Zoologicheskii Zhurnal [Zoological Journal] 67: 1149–1161, 1988,
with permission.)