oa Journal of East African Natural History - Migration of the butterflies Glycesthia aurota, Catopsilia florella and Crenis occidentalum in East Africa in 1967-68
The complex patterns of insect migration in Africa are not well understood for even the two commonest pierid migrants Glycesthia aurota Fab. and Catopsilia florella L. For a review of existing records and illustrations of these two species see Williams (1958), and for the most recent discussion of the problems involved, Johnson (1969). From July, 1967 to July, 1968 all butterflies which appeared to be migrating (most fly below 20 ft. and are very conspicuous) were counted for five minutes (Table I) as they crossed an open area 50 yards wide in front of my office at the Botany Department, University College, Nairobi. Field trips away from Nairobi generally took less than one week and, as major migrations usually take longer than this, probably few were missed during the year. No attempt was made to select days or times of day of special abundance for the counts, which were made whenever butterflies were sufficiently numerous to be noticed. Wind direction varied and did not seem to affect orientation at all, but most movement occurred in sunshine. The butterflies were identified from collections in the National Museum, Nairobi.
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