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Some effects of weather and moonlight on light-trap catches of the army-worm, Spodoptera exempta (Walker) (Lepidoptera: Noctuidae), at Muguga, Kenya

Published online by Cambridge University Press:  10 July 2009

R. J. Douthwaite
R. J. Douthwaite
Affiliation:
Centre for Overseas Pest Research, College House, Wrights Lane, LondonW8 5SJ, UK
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Abstract

The effects of wind speed, wind direction, strong moonlight and rainfall on hourly light-trap catches of adult Spodoptera exempta (Wlk.) made at Muguga, Kenya, between January and June in 1970 and 1971 were investigated. The highest catches occurred in winds of 2–3 m/s, but generally, fewer moths were caught as wind speed increased. In totally dark hours the geometric mean catch at wind speeds of 5–6 m/s was about one-tenth that at 0–1 m/s. The relationship between catch and wind speed changed between January and June. Wind direction and change in direction were not significantly related to catch. The geometric means of catches made in strong moonlight were about one-tenth those in total darkness at comparable wind speeds. Rainfall was associated with higher catches in seven out of eight months, but the differences were significant in only two months. Recognition of the association between light winds and large numbers of S. exempta should assist forecasting, but a fuller understanding of the relationship between light-trap catch and population requires a method of population assessment that is independent of the effects of weather and moonlight.

Type
Original Articles
Information
Bulletin of Entomological Research , Volume 68 , Issue 4 , December 1978 , pp. 533 - 542
Copyright
Copyright © Cambridge University Press 1978

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References

Aidley, D. J. (1974). Migratory capability of the African armyworm moth, Spodoptera exempta (Walk.).—E. Afr. agric. For. J. 40,202–203.CrossRefGoogle Scholar
Betts, E. (1976). Forecasting infestations of topical migrant pests: the desert locust and the Africian armyworm, pp. 113–134 in rainey, R.C. (Ed.). Insect flight. —287 pp. Oxford, Blackwell Scientific (Symp. R. ent. Soc. Lond. no.7).Google Scholar
Bowden, J. & Morris, M. G. (1975). The influence of moonlight on catches of insects in light-traps in Africa. III. The effective radius of a mercury-vapour light-trap and the analysis of catches using effective radius.—Bull. ent.Res. 65, 303–348.CrossRefGoogle Scholar
Brown, E. S., Betts, E. & Rainey, R.C. (1969). Seasonal changes in distribution of the African armyworm, Spodoptera exempta (Wlk.) (Lep., Noctuidae), with special reference to eastern Africa. —Bull. ent. Res. 58, 661–728.CrossRefGoogle Scholar
Haggis, M. J. (1971). Light-trap catches of Spodoptera exempta (Walk.) in relation to wind direction.—E. Afr. agric. For J. 37, 100–108.CrossRefGoogle Scholar
Ramsey, R. (1966). Low-level wind flow at Nairobi.—Met. Mag., Lond. 95, 47–57.Google Scholar
Siddorn, J. W. & Brown, E. S. (1971). A Robinson light trap modoified for segregating samples at predetermined time intervals, with notes on the effect of moonlight on the periopdicity of catches of insects.—J. appl. Ecol. 8, 69–75.CrossRefGoogle Scholar