Invasive Stink Bugs and Related Species (Pentatomoidea)

(Tuis.) #1

Nezara viridula ( L .) 369


It is common for laboratory studies to not provision first instars with a food source because of earlier
reports indicating that these nymphs do not feed. The findings of Esquivel and Medrano (2014) broach
the issue of whether fitness of first instars is being compromised when these insects are not provided
a food source. Although these authors re-defined the feeding behavior of these nymphs, questions still
remain regarding the amount of resources ingested during this stadium and the potential impact of
these ingested resources on subsequent life stages. This is further emphasized because cohorts of these
nymphs were allowed to molt and the pathogen also was detected in second instars, demonstrating reten-
tion of the marked pathogen through the molting process (Esquivel and Medrano 2014). The importance
of ingestion and retention of pathogens by first instars is amplified further when one considers that adult
Nezara viridula can transmit Pantoea agglomerans (Ewing) Fife, a pathogen that causes seed- and boll-
rot disease in cotton (Medrano and Bell 2007; Medrano et al. 2007, 2009a,b; Esquivel et al. 2010; also
see Chapter 13). Ingestion of P. agglomerans by early instars and retention of this pathogen through
later instars and into adulthood could have implications for management of N. viridula (e.g., through
more stringent thresholds).


7.4.1.3 Adults


Developmental time from egg to adulthood is approximately 30 days but will greatly vary based on
rearing temperatures and food source. Nondiapausing adults began mating as early as 5 days for females
and 6 days for males, indicating females reach sexual maturity earlier than males (Figure 7.1C; Mitchell
and Mau 1969, Musolin and Numata 2003a). Mated females deposited viable eggs within 7–8 days after
mating. This premating period (= precopulation period) differs from that reported by Fortes (2010).
However, the time frame for oviposition corresponds with Fortes (2010) and Fortes et al. (2011) who
observed chorionated eggs ready for fertilization at 10 days of age. Detailed descriptions of changes
to the developing and presumably senescing (i.e., late-season) reproductive systems can be found in
Esquivel (2009, 2016b).
Longevity of adults is variable and greatly depends on whether a particular adult reproduces directly
or enters winter diapause and reproduces after overwintering. Thus, under summer field conditions
in central Japan, nondiapausing (i.e., actively reproducing) adults lived on average less than 50 days,
whereas those adults that emerged later in the season (e.g., in September) entered diapause and survived
until the next summer (most of this time in diapause), began reproducing in April–May, and died in
July–August (Musolin et al. 2010).
In the laboratory, at 25°C, postdiapause females lived up to 351 days (including a long diapause period)
(Musolin et al. 2007). Fecundity of females also is variable. Under laboratory conditions at 25°C, fecun-
dity of reproductive females ranged from 18 to 1,496 eggs, and 1 to 19 egg clusters, per female (Musolin
and Numata 2003a, Musolin et al. 2007).
As noted earlier, adults exhibit several color morphs (see Section 7. 2) including gold (or orange),
blue, green, and black forms (Figure 7.1E–H). Although the green and orange forms have been
known for some time (Yukawa and Kiritani 1965, Kiritani 1970, Vivan and Panizzi 2002, Golden
and Follett 2006), a blue form was observed in a field collection in Brazil in 2015 (Antônio R.
Panizzi, personal communication) and, most recently, a black form was reported in a laboratory col-
ony in Texas (Esquivel et al. 2015). In all likelihood, polymorphism is under genetic control (Ohno
and Alam 1992, Follett et al. 2007, Musolin 2012) and seasonal color polymorphism is under abi-
otic influences (Figure 7.1C,D; see Section 7.4.4.2 and Chapter 11; Musolin and Numata 2003a,
Musolin 2012).


7.4.2 Symbiotic Relationships


Heteropterans possess endosymbiotic organisms in their gut and gastric caeca (Glasgow 1914, Malouf
1933). Glasgow (1914) observed bacteria in embryos of Murgantia sp., suggesting that endosymbiotic
bacteria are transferred from the gut (or gastric caeca) through the germaria walls into the egg; how
this transfer occurs remains unknown. Similarly, Nan et al. (2016, and references therein) observed
movement of yeast-like symbionts from the fat bodies to the developing oocytes of brown planthopper,

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