Submitted to: Environmental Entomology
Publication Type: Peer reviewed journal
Publication Acceptance Date: 10/28/2008
Publication Date: 3/1/2009
Citation: Prado, S., Golden, M., Follett, P.A., Daughtery, M., Alameida, R. 2009. Demography of gut symbiotic and aposymbiotic Nezara viridula (L.) (Hemiptera: Pentatomidae). Environmental Entomology. 38: 103-109. Interpretive Summary: The cosmopolitan pest, Nezara viridula (southern green stink bug), has gut associated bacterial symbionts. Tests were conducted to determine if the symbionts were important to fitness in the insect. Various life history traits were measured in symbiotic and aposymbiotic (sterilized; bacteria removed) bugs at three temperatures. Development time increased with decreasing temperatures but differences between symbiotic and aposymbiotic bugs were not significant. Life table analysis of N. viridula adults showed that net reproductive rate, intrinsic rate of increase, finite rate of increase, and gross reproductive rate were not significantly different among sterilized and normal bugs.
Technical Abstract: Nezara viridula (L.) is a highly polyphagous and cosmopolitan pentatomid stink bug. Despite its economic importance, aspects of its biology are poorly understood. Nezara viridula has one primary bacterium associated with the gastric caeca, which females provide to offspring by smearing it on the surface of eggs during oviposition. We studied the impact of three temperatures and egg mass surface sterilization on N. viridula’s nymphal development rate and reproductive performance. Our results demonstrate that maintenance of the symbiont is affected both by temperature and by egg mass surface sterilization. We detected the symbiont in 100%, 84% and 8.3% of the untreated control insects at 20, 25 and 30ºC, respectively, by using PCR. In insects originated from surface sterilized egg masses, the symbiont was never detected at 20 or 30ºC, and was detected in only 1 out of 21 insects at 25ºC. Nymphal mean development time decreased with increasing temperature, but there were no differences between the sterilized and control treatments. Sterilized insects at 20ºC lived longer than insects in any other treatment, but never laid eggs. Life table analysis of N. viridula adults showed that net reproductive rate, intrinsic rate of increase, finite rate of increase, and gross reproductive rate were not significantly different among treatments except at 20ºC for the surface sterilized treatment. Mean generation time, however, was significantly longer at 20ºC (70.96±4.43) regardless of sterilization. Our results highlight the effect that temperature has on the maintenance of this symbiosis and its relationship with N. viridula host’s development and reproductive life.