The microbial community interacts with the environment and the health and immune function of its host both directly and indirectly. However, very few studies about microbial communities have considered habitat and external environmental variables. This study examined environmental influences on the microbial community of Pachygrontha antennata, which is found in various habitats (e.g., urban, forested, and agricultural areas). The results demonstrated that the composition of the microbial community differed according to land use, while the bacterial diversity did not. In urban areas with high environmental heterogeneity, microbial community diversity tended to be high. Furthermore, bacteria in forests and agricultural areas (e.g., Paraburkholderia, Burkholderia) have been found to be highly correlated with habitat variables. Therefore, we suggest that habitat variables should be considered in future symbiotic studies.

In this study, we investigated the occurrence patterns and densities of cicadas in 18 urban parks in Seoul, Korea. Considering the ecological characteristics of cicadas that occured only in summer, the temporal changes of cicadas were investigated every week from June to September in 2017. Cicadas densities were measured using the final instar exuviae of cicada, which showed distinct morphological differences between species. A total of 7,369 cicada exuviae of six species were collected, and the dominant species in urban park were Hyalessa fuscata (44.8%) and Cryptotympana atrata (41.7%). There was no clear difference in the pattern of occurrence by species, but it occurred most frequently around August when the rainy season ended.

Endosymbiotic bacteria influence the ecology and evolution of insects through complex associations within host cells. To explore how these relationships vary among environments and taxa, we examined 1028 insect specimens from 14 orders across Korea for infections by three representative endosymbionts (Wolbachia, Rickettsia, and Spiroplasma). Overall, 33.8% of specimens were infected, with single infections predominating and co-infections remaining relatively less common. Weak-to-modest but statistically significant associations were detected between several symbiont pairs (Rickettsia–Spiroplasma, Wolbachia–Spiroplasma, and Wolbachia–Rickettsia). Infection rates exhibited no significant variation among host orders except for Spiroplasma, and Wolbachia infections were more frequently detected in terrestrial than in aquatic insects. These results indicate that endosymbiont infection patterns might be shaped by factors operating at multiple biological scales, including host taxonomy and habitat types. As this study relied on polymerase chain reaction detection, infection frequencies should be interpreted as comparative rather than absolute measures. This survey provides baseline data that might help characterize regional patterns of endosymbiont distributions and their variation across taxonomic and ecological contexts.

This study investigates the relationship between cicada emergence patterns and climatic variables (temperature and humidity) in two urban parks in Seoul, Asian Park and Cheongdam Park. Weekly collections of cicada exuviae were conducted during the summers (June to August) from 2015 to 2017 to analyze emergence rates and their associations with climatic factors. A total of six cicada species were identified, with Hyalessa maculaticollis being the dominant species in Cheongdam Park (76.2%) and Cryptotympana atrata in Asian Park (54.3%). Emergence rates increased from mid-July, peaked in early August, and exhibited an overall upward trend during the study period. The observed differences between the parks appear to stem from variations in microclimatic conditions. Asian Park, characterized by open and flat urban landscapes, consistently recorded higher average temperatures over the three years. In contrast, Cheongdam Park, with its cooler oak-dominated, semi-forested environments, maintained more consistent microclimatic conditions within the urban setting. This study highlights the role of cicada emergence patterns in reflecting urban microclimatic conditions and provides baseline data for understanding the ecological impacts of urbanization and climatic variability.

Synchronous emergence is a widespread adaptive strategy in cicadas, yet the proximate cues governing its timing in urban environments remain poorly understood. We examined the emergence phenology of three common urban cicada species (Cryptotympana atrata, Hyalessa maculaticollis, Graptopsaltria nigrofuscata) across two urban parks with contrasting habitat structure (a closed-canopy urban forest park vs. an open urban park) in Seoul, South Korea, over three summers (2015–2017). Despite interannual variation in rainfall amount and timing, peak emergence consistently occurred about two weeks after the monsoon rainfall peak. Poisson generalized estimating equation (GEE) analyses confirmed that antecedent precipitation at a 2–3-week lag significantly increased emergence counts across all three species, while precipitation one week prior had no significant effect. Emergence synchrony varied among species and habitat conditions, but the rainfall–emergence lag relationship was robust across years and sites. These findings demonstrate that precipitation timing is a key driver of peak cicada emergence in urban habitats. As East Asia experiences increasingly variable monsoon rainfall under climate change, understanding precipitation-based phenological cues will be essential for predicting the dynamics of urban insect populations.