Use of Insect Folivory in Biomonitoring of Particulate Matter in Shrubs of Makati and Manila

Abstract

Particulate matter has been a growing concern affecting the environment and human health. However, there are limited and conflicting studies regarding the role of particulate matter on the folivory in plants. As such, this study aims to assess the use of insect folivory as a biomonitor of particulate matter in the shrubs found in Makati and Manila City. A total of 60 attached leaves were sampled from different shrub species along the major roadsides. The total leaf area, consumed leaf area, and folivory index were obtained through the LeafByte mobile application, and PM2.5 and PM10 concentrations were recorded using Plume Labs real-time air quality mobile application. Results showed that particulate matter in Makati and Manila City had no significant difference, while the insect folivory index differed at various roadsides, including the common species in Makati and Manila City. Furthermore, a significant negative correlation was determined between particulate matter and insect folivory index, indicating an inverse relationship between the two variables (P < 0.05). This may be due to the adverse effect of the high concentration of particulate matter on low insect folivory and the advantageous effect of the low levels of particulate matter on high insect folivory. With this, insect folivory acts as an exemplary biomonitor of air pollution. This study provides baseline information on evaluating particulate matter and its effect on insect folivory. Consistent evaluation of air pollutants and urban greening development is necessary for the mitigation of the impact of air pollution and the restoration and monitoring of roadsides, acting as valuable habitats for diverse flora and fauna.