Foraging behaviour of Apis cerana indica and Apis mellifera in pollinating apple flowers
L. R. Verma And P. C. Dulta
The foraging behaviour of A. mellifera and A. c. indica honeybees on apple flowers was studied at three altitudes in the north-west Himalayas (1350, 1875 and 2400 m above sea level). A. cerana indica began to forage earlier in the morning than A. mellifera and stopped later in the evening at all three altitudes. Foraging trips by A. mellifera lasted significantly longer (P0·01). In both species nectar collectors outnumbered pollen collectors (P<0.01), the mean ratio of pollen to nectar collectors being 1:2.08 for A. c. indica and 1 :2.78 for A. mellifera. Peak foraging activity for A. c. indica occurred at 09.00-11.30 h. min when the temperature ranged between 15.5 and 21°C and 11.00-13.30 h. min for A. mellifera when the temperature was 21 to 25°C. By placing both species in the same orchard the duration of peak activity might be prolonged and better pollination obtained. Foragers of A. mellifera carried significantly heavier pollen loads, touched more stigmas and remained longer on individual apple flowers than those of A. c. indica. Altitude affected the times of initiation and termination of foraging activity and the duration of a foraging trip but not other behavioural parameters such as preference for nectar or pollen, peak time of foraging, pollen load, number of stigmas touched or average time spent in visiting a flower.