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Lake flies in Lake Victoria: Their biomass and potential for use in animal feeds

Published online by Cambridge University Press:  19 September 2011

J. Okedi
J. Okedi
Affiliation:
Department of Zoology, Makerere University, P. O. Box 7062, Kampala
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Abstract

Insects exhibiting swarming habits in Lake Victoria include mainly the Chironomidae, the Chaoboridae and Povilla adusta (Ephemeroptera). Their early life cycles are spent in the lake as benthos and standard bathymetrie procedures were undertaken to estimate the standing crop biomass of the larvae in Murchison Bay. Povilla was principally a boring invertebrate preferring dried logs (113 g Povilla nymphs per kg of host plant material). Cyperus papyrus carried 5 g C. denudalas 2.5 g and Phragmites mauritanus 1.0 g of Povilla per kg of host plant material. Povilla also occurred in the benthos at 40 g/m2. The Chironomidae and Chaoboridae had a mean standing crop biomass of 80 g/m2 and 3 g/m2 respectively. Their total biomass for the bay was estimated at 16060 metric tonnes for the Chironomidae, 7920 m. t. for Povilla and 660 m. t. for the Chaoborids. Adult swarming habits of the lakefly were closely correlated with lunar phases and the adults were easily trapped at night using kerosene lamps. Biochemical tests of the nutrient value of lakefly showed high levels of protein content (62%), minerals (18%), a low fat content (3.9%) and low moisture content (9%). This makes the lakefly ideal as an additive in animal feeds and growth experiments with poultry and aquaculture fish are currently going on to test the suitability of lakefly as an ingredient in animal feeds.

Résumé

Les insectes essaiment dans le Lac Victoria comprennent surtout les Chironomidae, les Chaoboridae et Povilla adusta (Ephemeroptera). La première partie de leur cycle est passée dans le Lac comme benthos et des proced ures standard de Bathymetrie étaient utilisées pour estimer la biomass des larves dans Murchison Bay. Povilla était principalement un invertebre qui préfère des pièces de bois sèche (113 gr Povilla nymphes par kilo de matériel végétal). Cyperus papyrus avait 5 gr., C. dennatus 2.5 gr., et Phragmites mauritanus 1.0 gr. de Povilla par kilo de matériel végétal. Povilla était aussi présent dans le benthos avec une densité de 40 gr. par metre carre. Les Chironomidae avait une densité moyenne de 80 gr. par metre carre, les Chaoboridae 3 gr. par metre carree. La biomasse totale de Murchison Bay est estimée à 16060 tonnes pour les Chironomidae, 7920 tonnes pour Povilla et 660 tonnes pour les Chironomidae, 7920 tonnes pour Povilla et 660 tonnes pour les Chaoborides. Le comportement d'essaimage des mouches du lac était en forte correlation avec le cycle de la lune, et les adultes était faciles à capturer pendant la nuit avec des lampes à kerosene. Des test biochemiques de la valeur nutritive des mouches du lac demontraient une haute contenance en proteine (62%), minéraux (18%), une faible contenance de gras (3.9%) et d'eau (9%). Cecl rend la mouche du lac une addition ideale pour la nutrition d'animaux, et des expériences avec des poules et aquaculture de poisson sont en cours, pour étudier la faisabilité d'utiliser cette mouche comme ingredient dans les nutritiments pour animaux.

Keywords

LakeflyPovilla adustaChironomidaeChaoboridaebiomassanimal feed
Type
Research Articles
Information
International Journal of Tropical Insect Science , Volume 13 , Issue 1 , February 1992 , pp. 137 - 144
Copyright
Copyright © ICIPE 1992

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References

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