Overwintering adult density and distribution in Plautia stali Scott (Heteroptera: Pentatomidae) and relationships of size of adult populations between the period of overwintering and the following spring-summer season

Leaf litter was collected for laboratory observation at overwintering sites of the brown-winged green bug, Plautia stali. No clear phenomenon of aggregation was detected from those leaf litter samples. Values of the index of contagiousness, Iδ were mostly close to unity. Density of over-wintering adults greatly fluctuated year by year, ranging from zero to 3.10, for the mean number of adults per sampling unit. When the total number of adult recruits at a mulberry thicket, one of the main habitats of this species, and the total number of catches in light traps in the spring-summer season were used as indicators of the population size after overwintering, the relationships between the overwintering adult density and each of these indicators were not simple but suggested density dependence. Possibility of utilizing overwintering density to monitor the population after overwintering was also discussed.