Authors:Boiteau, G., J. R. Bradley, Jr., J. W. Van Duyn, and R. E. Stinner
Title:Bean leaf beetle: micro-spatial patterns and sequential sampling of field populations
Summary:Pedigo 2002]">Dispersion of teneral and mature Cerotoma trifurcata (Forst.) in soyabean in North Carolina approximated to a negative binomial, with the single individual being the basic component of the distribution. Aggregation indices indicated departure from randomness but only a slight degree of clumping. The common k of the negative binomial was distinctly lower for young C. trifurcata than for mature ones. The degree of aggregation of mature adults was correlated with the seasonal fluctuations in abundance of the callow beetle. It is suggested that the oviposition behaviour of females is the causative factor of subsequent aggregation. Using sampling decision rules for adult beetles based on Morisita's I delta and Lloyd's coefficients, 30-50 random samples of 20 sweeps were adequate to estimate beetle densities in homogeneous soyabean fields. Simple sequential sampling methods suited to ecological population studies and estimation of population levels in relation to a predetermined threshold are suggested.