Environmental Entomology (1983) 12, 380-385

Joseph J. Reilly and Winfield L. Sterling (1983)
Dispersion patterns of the red imported fire ant (Hymenoptera: Formicidae), aphids, and some predaceous insects in east Texas cotton fields
Environmental Entomology 12 (2), 380-385
Abstract: Discrete frequency distributions, obtained from count data on Solenopsis invicta Buren, Aphis spp., Pseudatomoscelis seriatus (Reuter) adults and nymphs, Orius insidiosus (Say), Nabis spp., and Geocoris spp., in 1973 and 1974, were fitted to seven mathematical frequency distribution models. The negative binomial distribution best described the dispersion pattern of these insects in both years, indicating an aggregated, nonrandom dispersion pattern. The parameter k of the negative binomial distribution was used to quantify the aggregation of these insects. The maximum likelihood estimate and the moment estimate were two methods used to estimate the parameter k. A common k was calculated for each insect studied, to determine whether the estimated k values were common to all sampling dates over a season. As indicated by common k values, Aphis spp. and S. invicta were highly aggregated. P. seriatus nymphs were more aggregated than the adults. Among the predators, Nabis spp. were more aggregated than O. insidiosus; and Geocoris spp. were the least aggregated. Taylor's power law was fitted to the variance and mean density values for each insect. The power function well described the relation between the variance and mean density value for each insect.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)

Research topic(s) for pests/diseases/weeds:
population dynamics/ epidemiology
surveys/sampling/distribution
Research topic(s) for beneficials or antagonists:
surveys/distribution/isolation
population dynamics/epizootiology

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Solenopsis invicta		U.S.A. (mid S)
Orius insidiosus (predator)			U.S.A. (mid S)
Nabis (genus - predators)			U.S.A. (mid S)
Solenopsis invicta (predator)			U.S.A. (mid S)
Geocoris (genus - predators)			U.S.A. (mid S)
Pseudatomoscelis seriatus (predator)			U.S.A. (mid S)