Exploitation des fleurs de Ageratum conyzoides, Sida rhombifolia et Stylosanthes guianensis par Apis mellifera (Hymenoptera: Apidae) à Dang (Ngaoundéré, Cameroun)

A Dang (Ngaoundere, Cameroun), d’avril a decembre 2015 et 2016, les fleurs de Ageratum conyzoides L., Sida rhombifolia L. et Stylosanthes guianensis (Aublet) Swartz ont ete observees en vue de l’etude de l’activite de butinage de Apis mellifera L. Les fleurs de chacune de ces especes vegetales ont ete prospectees deux jours par semaine, les mercredis et vendredis, entre 7h 00 et 18h 00, periode subdivisee en trois tranches horaires (7h 00-11h 00, 11h 00-15h 00 et 15h 00- 18h 00). Les resultats montrent que les butineuses de A. mellifera frequentaient intensement et regulierement chacune de ces especes vegetales pour la recolte du pollen. Cette abeille prelevait fortement le nectar chez S. rhombifolia et S. guianensis . Chez A. conyzoides cette activite etait faible. Le plus grand nombre de butineuses de A. mellifera simultanement en activite sur 1000 fleurs variait de 54 ( A. conyzoides ) a 125 ( S. rhombifolia ). Ageratum conyzoides , S. rhombifolia et S. guianensis sont des plantes apicoles fortement polliniferes pouvant etre cultivees et protegees pour augmenter la production du pollen comme produit de la ruche. Sida rhombifolia et S. guianensis sont des plantes apicoles fortement nectariferes pouvant etre cultivees et protegees pour accroitre la production du miel. Sur chacune de ces plantes, les ouvrieres de A. mellifera transportaient le pollen de fleur en fleur et peuvent ainsi etre considerees comme des pollinisateurs. Mots cles: Ageratum conyzoides , Sida rhombifolia , Stylosanthes guianensis , Apis mellifera , plante apicole, pollinisation English Abstract At Dang, from April to December 2015 and 2016, Apis mellifera L. workers foraging activity was studied on the flowers of three plants species, Ageratum conyzoides L., Sida rhombifolia L. and Stylosanthes guianensis (Aublet) Swartz. At Dang, the flowers of each plants species were observed two days per week, the Wednesdays and Fridays between 07h.00 and 18h.00, for recording the pollen and/or nectar foraging behaviour of A. mellifera workers. Results show that, A. mellifera harvested intensely and regularly the pollen of each plant species. In addition, S. rhombifolia and S. guianensis were also visited intensely and regularly for nectar; A. conyzoides was also visited for nectar but slightly. The greatest mean number of workers foraging simultaneously on the flower was 1 for each plant species, per 1000 varied from 54 (A. conyzoides) to 125 ( S. rhombifolia ). Apis mellifera workers visited the flowers of plants species others during foraging bouts. Consequently, A. conyzoides , S. rhombifolia and S. guianensis are highly polliniferous bee plants that can cultivated and protected to increase pollen production as a hive product. Sida rhombifolia and S. guianensis are highly nectariferous bee plants that can be cultivated and protected to increase the honey production. During foraging, A. mellifera workers carried pollen from flower to flower and improved pollination possibilities of each plant species and can thus be considered as pollinator. Keywords: Ageratum conyzoides , Sida rhombifolia , Stylosanthes guianensis , Apis mellifera , bee plant, pollination