Table 1.
Megachile (Megachilidae) selected for study from different biomes in South Africa.
The number of specimens in the National Collection of Insects that contained pollen for sampling is also indicated, as well as the age range of specimens based on collection dates.
Table 2.
Summary statistics of merged reads (after quality and adapter trimming was performed, and subsequent merging of forward and reverse reads) of the six Megachile species investigated in this study.
Failed samples’ reads are excluded.
Fig 1.
Visual representation of the proportion of bee specimen samples in which each plant family was identified in each biome group.
Families from the phylum Chlorophyta were removed prior to plotting the graph. The family Pteridaceae was identified in nearly all samples in all three bee groups (Savanna, Succulent Karoo and widespread), with clear differences in the prevalence for plants belonging to Asteraceae, Fabaceae and Magnoliaceae by the widespread bee group. The absence of a group marker in a column indicates that the particular plant family was not detected in pollen loads from any bee specimens in that biome group.
Fig 2.
Frequency distribution of plant species detected in each bee species studied.
Bees from the Succulent Karoo (M. karooensis and M. murina) and Savanna (M. felina and M. maxillosa) show similar species abundances, with the two widespread bee species (M. niveofasciata and M. venusta) both detecting up to 14 different plant species each.
Fig 3.
Model-adjusted means for plant species OTUs detected in pollen samples in the three regions studied.
The mean number of species detected on bees from the Succulent Karoo (M. karooensis and M. murina) and the Savanna (M. felina and M. maxillosa) are lower than those on widespread bee species (M. niveofasciata and M. venusta). Means sharing a letter do not differ significantly at a 95% significance level after Sequential Dunn-Sidak post-hoc testing.
Fig 4.
Sample-based rarefaction curve to estimate plant species richness for each bee species studied.
Megachile venusta (e) was shown to have the highest estimated species richness. Sample labels represent bee species and are labelled as follows: (a) M. felina (b) M. karooensis (c) M. maxillosa (d) M. murina (e) M. venusta (f) M. niveofasciata.
Fig 5.
Non-metric multidimensional scaling (NMDS) analysis using Bray-Curtis distances representing plant species OTUs detected on bees from the three groups.
Bee species from the same region are represented by the same shape, and different bee species colour-coded. Bees from the Succulent Karoo are represented by squares, circles represent bees from the Savanna, and crosses represent widespread species.