Floraison et récolte du pollen par les abeilles domestiques (Apis mellifera L var ligustica) dans la pampa argentine

Abstract - Flowering and pollen collection by the honeybee (Apis mellifera L var ligustica) in the pampas region of Argentina
This paper reports pollen collection by bees and the relation with flowering phenology in different environments from one sector of the "pampa" phytogeographic province (Cabrera, 1963) (fig 1). The samples were collected from September 1985 to April 1986. The intensity of flowering (Anderson and Hubritch, 1940) and the relative abundance (Braun-Blanquet, 1950) were registered for each species in every environment. The pollens were collected with traps placed in 3 hives from 8-16 h. The sampling was carried out every fortnight. Figure 2 shows the percentage of species based on the geographical origin and figure 3 flowering of the native and exotic plants and pollen collection. Table I presents the data on flowering and pollen collection of the most important species together with field distributions, abundance and geographical origin. The pollen collection from herbaceous plants and shrubs throughout the season is compared in figure 4. Table II presents a list of least visited species grouped by botanical family and season. Under the ecological conditions of the Pampas, the foraging behaviour of bees is similar to that reported by other investigators (Louveaux, 1968, 1990; Battaglini Bernardini, 1970; Lobreau-Callen et al, 1986; Debbagh, 1988; Le Thomas et al, 1988). The most visited plant species, based on pollen collected during our study, also provide the predominant pollens in honey from the pampas region (Telleria, 1988, 1992). However, a very selective choice made by the honeybees within the Leguminosae and Compositae was found; this could be explained by a high degree of adaptation between the honeybees and the plants from the same continent.