212 Invasive Stink Bugs and Related Species (Pentatomoidea)
total nymphal stadia of ≈34 days at 25°C, with total developmental time from egg to adult averaging
≈42 days. Husain (1925) reported that the total developmental time from egg to adult took less than
three weeks at temperatures greater than 35°C. Not surprisingly, the total time required for nymphs
under various rearing conditions was variable, taking longer at cooler temperatures or when fed non-
brassicaceous plants (Rohilla et al. 2004).
The overall aggregation and feeding behavior of Bagrada hilaris nymphs generally is similar to that
of other pentatomids. Upon hatching, first instars do not appear to feed but remain closely associated
with the empty egg choria for several hours (Atwal 1959). Nymphs and adults may remain aggregated
throughout their lifetime but also disperse to locate nearby food sources (Dhiman and Gandhi 1988).
Under field conditions, it is common to find all stages together on a single host plant while other nearby
plants appear unoccupied and undamaged (Reed et al. 2013b). When disturbed, all stages disperse, either
dropping to the ground and/or quickly crawling down the plant to soil level.
As with nymphs (Taylor et al. 2015), there is evidence of color variation among adults. Darcy A.
Reed (unpublished data) has observed distinct differences in coloration of the venter of the abdomen.
Specifically, the venter is much lighter in color (predominantly cream-colored) in populations found in
hotter, drier areas than the venter in populations in colder, wetter areas, where it is predominantly black.
Aldrich (1986) has reported that the overall coloration in other pentatomids can be darker when the bugs
are reared under cooler temperatures.
The adult stage averages 8–26 days (Gunn 1918, Singh and Malik 1993, Colazza et al. 2004, Ghosal et
al. 2006) when feeding on preferred hosts. Females generally have been reported to survive longer than
males (Batra and Sarup 1962, Singh and Malik 1993, Ghosal et al. 2006); however, there are reports of
males living slightly longer than females (Rakshpal 1949, Verma et al. 1993). Adults have been reported
to live as long as 96 days (Hutson 1935), which may be a reflection of poor food quality.
Mating typically occurs within 2–6 days after eclosion (Rakshpal 1949, Batra and Sarup 1962,
Azim and Shafee 1986, Verma et al. 1993, Ghosal et al. 2006); however, mating has been reported as
early as 1 day after eclosion under certain conditions (Hutson 1935, Batra and Sarup 1962, Singh and
Malik 1993).
Guarino et al. (2008) described three phases of courtship/mating behavior. First, upon encountering
a female, the male antennates her body (“contact” phase). Second, the male mounts the female and con-
tinues to antennate her antennae and abdomen (“mount-antennation” phase). Finally, the male dismounts
and initiates copulation by placing his hind legs on the dorsum of her abdomen and backing his abdo-
men into hers (“engagement” phase). His wings take a position above hers to allow contact between the
genitalia of the two bugs. Courtship behavior may last seconds to minutes (Guarino et al. 2008), whereas
copulation may be greatly prolonged (several hours). Males tend to remain with females for prolonged
periods of time. Azim and Shafee (1986) reported copulation lasting 10–12 hours at a time, with pairs
separating when the female prepares to oviposit. Competing males often were found in close proxim-
ity to a copulating couple and could be found atop the couple awaiting an opportunity to mate with the
female (C. Scott Bundy and Darcy A. Reed, personal observations).
Following mating, there is a preovipositional period of 2–14 days before eggs are deposited (Rakshpal
1949, Batra and Sarup 1962, Azim and Shafee 1986, Singh and Malik 1993, Ghosal et al. 2006). A
single female has been reported to deposit up to 19 eggs per day (Rakshpal 1949) and from 36 to 217
eggs during her lifetime (Hutson 1935, Mukerji 1958, Batra and Sarup 1962, Singh and Malik 1993,
Verma et al. 1993).
Adults are active and present on plants primarily during the daytime (1300 to 1800 hours) with peak
mating activity occurring between 1000 and 1600 hours (Huang et al. 2013). They spend the majority
of their time in copula, and females exert more feeding damage than males during this time (Huang
et al. 2013). Undisturbed copulation may last approximately 12 hours and repetitive and multiple mat-
ings with different males are common (Azim and Shafee 1986). Unmated females do not lay eggs and
repetitive matings are not necessary for additional egg production (Rakshpal 1949). However, Thomas
M. Perring (unpublished data) observed infertile egg production from unmated females within 4 days
of adult emergence. He also observed that male replacement or repetitive mating increased number of