De. Legg et al., ESTIMATING DENSITIES OF GRASSHOPPER (ORTHOPTERA, ACRIDIDAE) ASSEMBLAGES USING BINOMIAL SAMPLING, Environmental entomology, 22(4), 1993, pp. 733-742
Counts of grasshoppers from Wyoming and New Mexico were related to the
proportion of 0.1-m2 samples that contained grasshoppers through bino
mial sampling models. Three models were investigated. One was based on
the Poisson probability density function and two were based on the Na
chman and logit binomial regressions. The Nachman and logit regression
s were tested extensively for an influence of predominant instar, samp
ling year, and location on the estimated parameters. Results indicated
that instar and sampling year did not influence the parameter estimat
es, but location did. All models were then tested to determine which p
rovided the smallest error for predicting densities from incidence and
vice versa. Results showed that no differences occurred between model
s. Based on this finding, the Poisson sampling model was selected for
use in wide-scale surveys because it is simple and easy to use. An ind
ependent data set from Montana was used to validate this model. Implic
ations of this and other findings in context of using binomial samplin
g as a management and research tool are discussed.