Original Articles

Pollination activity and behaviour of honeybees (Apis mellifera L.) in commercial sunflower in the Transvaal

Published in: South African Journal of Plant and Soil
Volume 9, issue 4, 1992 , pages: 168–172
DOI: 10.1080/02571862.1992.10634623
Author(s): A.P. du Toit, Republic of South Africa, E. HolmDepartment of Entomology, Republic of South Africa

Abstract

Honeybee foraging activity in commercial sunflower fields was studied at Settlers, 100 km north of Pretoria. Foraging activity, which was studied by means of the conventional strip count method, commenced after sunrise and reached a peak of 38 foragers per 100 capitula at 10:00. A moderate decline followed between 11:00 and 15:00 (mean number of 32 foragers per 100 capitula), whereafter another peak of 40 foragers per 100 capitula was reached two hours before sunset. Examination of returning foragers revealed that pollen foraging predominated until 09:00 and nectar foraging prevailed thereafter. Cross-pollination efficiency of honeybee foragers was good as more than 50% of foragers landed on the outer ring of florets and then moved to the inner ring where fresh pollen is available, before flying to the next head. Movement between heads was indiscriminate, which enhanced pollen movement.

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