Spatial distribution of small white butterflyPieris rapae(L.) in the cauliflower fields of Tehran

Abstract

One of the most basic information to understand insect population dynamics is the pattern of their spatial distribution. This study was conducted on spatial distribution of the small white butterfly, Pieris rapae (Lepidoptera: Pieridae), in the cauliflower fields in the south of Tehran from late May until October 2011. Each cauliflower plant was presumed to be a sampling unit. The pattern of spatial distribution was determined for each development stage of P. rapae by using regression models (Taylor’s power law and Iwao’s patchiness regression). The results indicated that the spatial distribution pattern was clumped for all life stages of P. rapae. In Taylor’s and Iwao’s models, the slopes of regression lines were more than one for all life stages. Also, population fluctuations of different stages of this pest were high during the season. The spatial distribution pattern can be used to improve the sampling programme, estimate the exact population density and to plan and perform integrated management of th...