Foraging Behaviour of Apis mellifera L. and Scaptotrigona bipunctata on Dombeya wallichii Flowers in Southern Brazil

This research was carried out to evaluate the foraging behaviour of Apis mellifera and Scaptotrigona bipunctata and its relationship with environmental variables in Dombeya wallichii considering the following aspects: 1) Type of resource harvested, 2) Visitation rate, 3) Length of visit, 4) sugar concentration in the stored nectar in the honey crop of A. mellifera and secreted by the flower and 5) floral constancy. Both species collected mainly nectar, with a visitation rate of 4.2 flowers for A. mellifera and 1.1 flowers for S. bipunctata and visit length of 9.2 and 34.2 seconds, respectively. The sugar concentration had a positive relationship with temperature and luminosity, with mean values of 12.3% in the nectar and 14.2% in the honey crop. Bees were classified by specialists because the pollen of D. wallichii was predominant in the pollen basket, but the pollen of Emilia sonchifolia and Raphanus sativus was also found. These results suggest that the species under study take advantage of the resources offered by D. wallichii, therefore, this species is an important source for the maintenance of the bees in the season of lack of food.