Landscape-scale spatial dynamics of Riptortus pedestris (Hemiptera: Alydidae): Implications for areawide management

Abstract

The bean bug, Riptortus pedestris (Fabricius) (Hemiptera: Alydidae) is highly mobile and has a wide host range, making field-by-field control difficult and inefficient. We conducted a 3-year spatial study to determine the potential for areawide management of R. pedestris by investigating their landscape-level population dynamics, characterizing the spatial distribution patterns of R. pedestris, and describing its seasonal movement in a landscape. The study site covered ca. 6.5km2 including typical suburban areas with forest and cultivated fields. A total of 24 georeferenced pheromone traps were deployed in the area and the number of R. pedestris caught in the traps was counted weekly. Data were analyzed with spatial analysis by distance indices (SADIE) and geographic information systems (GIS) to characterize the spatial distribution patterns of R. pedestris. This study identified four distinctive peaks of R. pedestris populations showed distinctive patterns of R. pedestris movement throughout the study site. The first and second peaks of R. pedestris populations were found in forested areas and field crops (e.g. soybean and rice), respectively, indicated by buffer analysis with GIS. Significant spatial aggregation was found at the third and fourth peaks by SADIE when R. pedestris propagated in soybean fields and moved to overwintering sites. The results of spatial association analyses confirmed that R. pedestris moved among different commodities and surrounding land-use types throughout the season. This study implies the potential of areawide management of R. pedestris in agricultural landscapes.