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Some factors affecting substrate preferences by black-fly pupae (Diptera: Simuliidae)

Published online by Cambridge University Press:  19 September 2011

D. M. Roberts
Affiliation:
Department of Zoology, University of Jos, P.M.B. 2084, Jos, Nigeria
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Abstract

A comparison was made of the relative abundance of three species of black-fly pupae colonising three natural substrates in the River Assob, in central Nigeria. Simulium hargreavesi, S. squamosum and S. vorax preferred trailing roots, whereas S. cervicomutum, S. unicomutum and S. impukane preferred dead leaves and to a lesser extent, rocks.

In order to see whether this was a preference between cylindrical and flat surfaces, polythene strips were compared with polythene strings and a smooth surface was compared with a rough one. Results are presented for the three most abundant species S. squamosum, S. hargreavesi and S. cervicomutum. All markedly avoided the rough string. S. squamosum and S. hargreavesi preferred smooth strings, whereas S. cervicomutum had no significant preference between smooth strips and strings (although slightly preferring strips). These findings are discussed in relation to natural habitats and sampling bias.

Résumé

On a fait une comparison de l'abondance relative de trois espèces des nymphes des simulies qui colonisent trois supports naturels de la rivière Assob au Nigeria central. Simulium hargreavesi, S. squamosum et S. vorax préféraient les racines traînantes pendant que S. cervicomutum, S. unicomutum et S. impukane préféraient les feuilles fanées, et un peu moins, les roches.

Pour voir si cette préférence venait des surfaces cylindriques ou plates, on comparait des bandes de polythene avec les cordes de polythene; au même temps on comparait une surface lisse avec une surface rugeuse. On présente les résultats pour les trois espèces les plus abondantes, S. squamosum, S. hargreavesi et S. cervicomutum. Tous n'ainaient pas les cordes rugeuses. S. squamosum et S. hargreavesi préferaient les cordes lisses, pendant que S. cervicomutum ainait presque également les bandes lisses et les cordes lisses; les bandes lisses etaient un petit peu plus populaires. On discute ces découvertes au rapport des habitats naturels et du biais des echantillons.

Type
Research Articles
Copyright
Copyright © ICIPE 1986

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References

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