Bulletin of Entomological Research (1989) 79, 145-161

G.P. Fitt, M.P. Zalucki and P. Twine (1989)
Temporal and spatial patterns in pheromone-trap catches of Helicoverpa spp. (Lepidoptera: Noctuidae) in cotton-growing areas of Australia
Bulletin of Entomological Research 79 (1), 145-161
Abstract: Helicoverpa armigera (Hübner) and H. punctigera (Wallengren) are major pests of cotton and other field crops in Australia. Using data on the abundance of males in pheromone traps at many sites over three seasons, the spatial and temporal variation in trap catch of both species were examined using Taylor's power law and spatial autocorrelation. The distribution of both species was highly clumped, both temporally and spatially. Regression coefficients for the relationship of spatial mean to variance (b_s) were similar to those for noctuids in general, while similarly derived temporal values (b_t) for H. armigera fell towards the upper end of the noctuid range and those for H. punctigera well above the range given by Taylor and Woiwood (1980). Taylor and colleagues suggested that patterns of dispersion are species specific and that they reflect density-dependent patterns of movement towards and away from centres of abundance. Although the relationship between variance and mean abundance for both spatial and temporal aspects of trap catches of Helicoverpa is well fitted by Taylor's power law, it is argued that these patterns of dispersion are a consequence of demographic and environmental stochasticity. Little need is seen to invoke specific density-dependent behaviours as the major factor responsible in this case. In addition, while Taylor's power law indicated both species had a similar clumped distribution, limited autocorrelation analysis suggested a random dispersion of pheromone-trap catches for H. armigera and small scale patchiness (over distances of 1-2 km) in trap catches of H. punctigera.
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Link to article at publishers website
Database assignments for author(s): Myron P. Zalucki

Research topic(s) for pests/diseases/weeds:
population dynamics/ epidemiology

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Helicoverpa armigera	Cotton (Gossypium)
	Helicoverpa punctigera	Cotton (Gossypium)