Species diversity of environmentally-transmitted bacteria colonizing Riptortus pedestris (Hemiptera: Alydidae) and symbiotic effects of the most dominant bacteria.

Riptortus pedestris (Hemiptera: Alydidae) establish endosymbiosis with specific bacteria from extremely diverse microbiota in soil. To better understand ecology and evolution of the symbiosis, it is important to characterize bacterial species diversity colonizing R. pedestris and evaluate their symbiotic effects. Nonetheless, previous research was limited to a few bacteria strains such as Caballeronia insecticola. In this study, second-instar nymphs were provided with field soils and reared to adult. Then, bacteria colonizing the midgut M4 region of R. pedestris were analyzed for bacterial species identification based on the 16S rRNA gene. First, a total of 15 bacterial species were detected belonging to Burkholderiaceae. Most of R. pedestris were found to harbor single bacterial species, whereas several insects harbored at most two bacterial species simultaneously. Among the total insects harboring single bacterial species, 91.2% harbored genus Caballeronia. The most dominant species was C. jiangsuensis, not previously documented for symbiotic associations with R. pedestris. Second, in laboratory conditions, C. jiangsuensis significantly enhanced the development, body size, and reproductive potentials of R. pedestris, compared to individuals with no symbiotic bacteria. These results add novel information to better understand symbiotic bacteria community establishing in R. pedestris and symbiotic effects on the host insects.

Dispersal and oviposition patterns of Lycorma delicatula (Hemiptera: Fulgoridae) during the oviposition period in Ailanthus altissima (Simaroubaceae).

The spotted lanternfly (SLF), Lycorma delicatula (Hemiptera: Fulgoridae), has the potential to become a global pest and is currently expanding its range in the United States. In this study, we investigated the dispersal patterns of SLF in Ailanthus altissima during its oviposition period in South Korea using a fluorescent marking system. Oviposition patterns of SLF were then analyzed by surveying egg masses in A. altissima patches. The recapture rate of fluorescent-marked SLF rapidly decreased to 30% within the first two weeks. During the oviposition period, seven cases of among-patch dispersal of SLF adults were observed. The minimum distance that SLF could have traveled to achieve these among-patch dispersal events ranged from 10 to 1740 m, with most events spanning under 60 m. Also, the number of A. altissima trees on which fluorescent marked SLF were detected increased until September. Based on the egg mass survey, a total of 159 egg masses were detected from 38 out of 247 A. altissima trees. Furthermore, 79.2% of egg masses were located < 2.5 m above the ground. Finally, a generalized linear mixed model showed that tree height and diameter at root collar (DRC) of A. altissima trees had significant effects on the number of egg masses.