Occurrence dataset of wild bees (Hymenoptera, Apoidea) present in agricultural and non-farmed landscapes of Central Uganda

Study Extent

Bees were collected from 34 sample plots established in farmland, grassland, and natural woodland areas to represent different land-use categories. The site was pre-selected based on the advice of sub-county extension staff and community leaders. Thereafter ground-truthing was done and 100m x100m plots delineated and georeferenced using a hand-held GPS device (Garmin; eTrex 10, Garmin Ltd, Taiwan). Surveys were conducted in wet and dry season periods for two years. Each round of sampling was 8-10 days long. Sampling rounds were separated by a 6-8 week period. Eight surveys, equivalent to 266 sampling events were conducted over the two years.

Sampling

Bees were collected using a combination of UV-reflecting pan traps (yellow, white, and blue) and sweep-netting techniques. Each plot was subdivided into five sub-plots measuring 20m x 20m; one sub-plot at each corner and the fifth in the center of the main plot. Additionally, two 2m wide by 50m long transects were set in an X-fashion across the main plot. A transect walk while sweep-netting was conducted along each transect for 20 minutes, giving a total of 40 minutes of sweep-netting per plot. Collected bees were transferred into 20ml vials of 70% ethanol. In each sub-plot, three pan-traps (one of each color) were placed on the ground, in plots that had less than 10cm high vegetation or, on 50cm high stakes in plots whose vegetation exceeded 10cm in height. Each pan-trap was filled with 200-300 ml of water to which a few drops of scentless liquid detergent had been added to break the surface tension. Pan-traps were recovered 30-36 hr later and the contents were decanted into 20ml vials containing 70% ethanol. For some events, opportunistic sampling using sweep nets was undertaken for 30-40 minutes in areas adjacent to the sample plots. In the lab, bees from each sampling event were dried, pinned, sorted into morphospecies groups, and identified first to genus level. Species identifications were done thereafter by collaborating bee systematists.

Method steps

1. Farmland included perennial gardens of Robusta coffee and subsistence gardens of short-term food crops like legumes, vegetables, and starchy staples (root crops, maize). Grasslands were mixed species grasses interspersed with herbaceous weeds and used for grazing. Woodland included degraded savanna woodland and one Eucalyptus plantation

Uganda. Bees were collected from Nakaseke, Luwero, and Kayunga districts. These districts lie within the southern part of the Lake Kyoga basin and the northeastern reaches of the Lake Victoria Basin agroecological zones.