The Behaviour of a Population of Honeybees on an Artificial and on a Natural Crop

Abstract

One hundred and twelve Petri dishes filled with sugar syrup were arranged at 20 yd. intervals from each other in a meadow. Individual bees were observed to visit one chosen dish with great regularity for one or more days, provided that the supply did not become exhausted. Occasionally bees maŕked on one dish were observed to visit an adjacent dish. This occurred most frequently when the supply of syrup temporarily failed at the original site of feeding, but, even after a 3-day interruption in the syrup supply bees often returned to feed at the original site. Bees feeding at a dish full of syrup spent only a fraction of their time (about 1 min.) per visit drinking, but several times as long flying to and from the hive and delivering their load. When the supply of syrup in a dish became exhausted all the bees accustomed to visit that dishgradually accumulated there impatiently seeking for food; after some minutes they extended their radius of search, and many located another source near at hand. Thereafter they visited either the new source or the old, or both, when the syrup at the original site was replenished. The nearer such a new source was to the original one the more likely a bee was to find it; a dish 20 yd. away from the original site was quickly found despite the fact that such a second dish would seldom be visited if the syrup at the original site was constantly maintained. Bees were deterred from collecting syrup from dishes placed even partially in shade; they veryseldom worked beneath the shade of trees. There were even some indications that they prefered not to fly in the direction of shady trees. Over the range of distances covered (160-400 yd.) there were always more visitors to the nearer than to the more distant dishes. The extent of this difference, however, varied from day to day. Bees accustomed to collect syrup from the dishes farthest from the hive did not move to sites nearer home when the weather became unfavourable. There was some evidence, however, that bees working a long way away from the hive were more easily deterred, from foraging by unfavourable weather than those working close to the apiary. When two different concentrations of syrup were offered in different groups of dishes simultaneously the number of visitors to the dishes containing the syrup of high concentration rose considerably higher than that of the visitors to the dishes containing low-concentration syrup; even after all the dishes had been refilled with syrup of uniform concentration on the following day, this difference remained noticeable. Bees marked on a patch of willow-herb (Epilobium angustifolium) situated in the midst of a large crop of this plant, were usually recovered within 5 yd. of the point of marking. Such bees remained ‘fixed’ to this area for several days. Observations were made upon isolated patches of the cultivated thistle; Echinops sphaerocephalus, of bees which continued to visit the patches upon which they were marked for periods up to 16 days. The majority of the bees working the patches showed great constancy: and of such regular visitors the percentage per day observed to stray to other patches of Echinops 18 yd. away was comparatively small. The time spent by foraging bees upon the flowerheads of Echinops on any one visit greatly exceeded the time spent in collecting syrup from a dish (20-60 min. as against 1 min.); but the time spent in flying between the hive and the flowers, or dish, and unloading was approximately equal in each case. Only a small proportion of the population of bees working on a particular dish could be found feeding there at any one time, whereas on a patch of flowering plants, under good weather conditions, most of the population visiting that patch would be found there at any one time. This great difference in behaviour on dishes as compared with plants must be borne in mind in any attempt to draw conclusions from dish experiments as to the behaviour of bees.