Megacopta cribraria ( F.) 309
(2008) stated that data labels on specimens of the genus Synona Pope (Coccinellidae) indicated the
involved species were predators of Coptosoma spp. and M. cribraria.
Megacopta cribraria appears to be attacked by a number of predators in its invasive range. Ruberson
et al. (2013) listed the following species that were observed feeding on M. cribraria in the laboratory or
field: Euthyrhynchus floridanus (L.) (Pentatomidae); Nabis roseipennis (Reuter) (Nabidae); Geocoris
uliginosus (Say), G. punctipes (Say) (Geocoridae); Zelus sp., Sinea sp. (Reduviidae); Hippodamia con-
vergens Guérin-Méneville (Coccinellidae); and Chrysoperla rufilabris (Burmeister) (Chrysopidae).
Greenstone et al. (2014) used molecular analysis of gut content to determine predators of M. cribraria
in soybean and cotton fields. Nine predators tested positive for DNA of the bug as follows: G. punctipes,
G. uliginosus; Orius insidiosus (Say) (Anthocoridae); Podisus maculiventris (Say) (Pentatomidae);
H. convergens; Zelus renardii (Kolenati) (Reduviidae); Oxyopes salticus Hentz, Peucetia viridans
(Hentz) (Oxyopidae); and Solenopsis invicta Buren (Formicidae). Leslie et al. (2014) provided a photo-
graph of Xysticus sp. (Thomisidae) feeding on an adult of M. cribraria.
5.4.3.4 Pathogens
Only one pathogen, the fungus Beauveria bassiana (Balsamo) Vuillemin (Clavicipitaceae), has
been reported from Megacopta cribraria. Borah and Dutta (2002) first reported this pathogen from
M. cribraria on pigeon pea in India with 31.5% of bugs infected in 1997 and 19.3% in 1998. Pathogenicity
was confirmed using Koch’s postulates (Borah and Dutta 2002, Borah and Sarma 2009b) by culturing
the fungus and reinfecting healthy individuals. They obtained 60–72% mortality of adults and 63–83%
of nymphs treated with aqueous spore suspensions in the laboratory.
Ruberson et al. (2013) reported the occurrence of Beauveria bassiana in Georgia in single individ-
uals of Megacopta cribraria found in kudzu and soybean. In South Carolina, Seiter et al. (2014a) also
found these bugs infected with B. bassiana and confirmed identity and pathogenicity with Koch’s
postulates. Initial infestation levels in field plots averaged about 7% at peak density and ranged from
9.1 to 78.5% in plots treated with conidial suspensions, depending on density of the bugs. During
the 2014 and 2015 growing seasons, widespread and significant epizootics of B. bassiana have been
reported in soybeans in Georgia and South Carolina (Wayne A. Gardner, personal communication).
In 2015, B. bassiana infected an average of 75.5 % of immature M. cribraria and 33.4 % of adults in
two counties in eastern Tennessee (Britt et al. 2016). Late in the season mortality of immatures was
as high as 100 % while the highest mortality of adults was a little over 60 %. In a laboratory assay
(Portilla et al. 2016), strains of B. bassiana isolated from M. cribraria and Lygus lineolaris (Palisot
de Beauvois) (Miridae) were highly effective against M. cribraria, with an LC 50 of 1.98-4.98 viable
spores per mm^2. These results suggest that B. bassiana has become an important biological control
agent for this bug.
5.4.4 Endosymbionts
Megacopta species are phloem feeders, which is a carbohydrate-rich, but amino acid and vitamin-poor,
food. Yet, these phloem feeders thrived, adapted, and dispersed rapidly into new environments (Prentis
et al. 2008). This has been shown, in part, to be due to an intimate association with vertically transmit-
ted bacterial endosymbionts in which insect and endosymbiont are interdependent or obligate partners
(Moran 2001; Hosokawa et al. 2006, 2007b). Data are accumulating that show such insect-bacteria sym-
biosis serve to enhance the invasive adaptive potential of an insect (Moran 2007) by providing insects
with the ability to adapt not only to nutrient-poor food sources (Gruwell et al. 2010) but to changing
environments (Moran 2001).
Ovipositing females of Megacopta cribraria lay eggs in two rows and deposit small dark capsules
under the eggs, generally between the two rows (Figure 5.1B). Fukatsu and Hosokawa (2002) found
that the capsules contained a gammaproteobacterial endosymbiont that was not found in the eggs, dem-
onstrating that it was transmitted orally rather than transovarially. First instar nymphs feed directly
on these capsules to obtain the symbionts. Removal of the symbiont capsules results in bugs that show