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While global patterns of bee diversity have been modelled, our understanding of fine‐scale regional patterns is more limited, particularly for under‐sampled regions such as Africa. South Africa is among the exceptions on the African continent; its bee fauna (ca. 1253 species) has been well collected and documented, including mass digitising of its natural history collections. It is a region with high floral diversity, high habitat heterogeneity and variable rainfall seasonality.Here, we combine a South African bee species distributional database (877 bee species) with a geospatial modelling approach to determine fine‐scale (~11 × 11 km grid cell resolution) hotspots of bee species richness, endemism and range‐restricted species.Our analyses, based on the probabilities of occurrence surfaces for each species across 108,803 two‐minute grid cells, reveal three bee hotspots of richness: Winter rainfall, Aseasonal rainfall and Early‐to‐late summer rainfall. These hotspots contain large numbers of endemic and geographically restricted taxa. Hotspots with particularly high bee diversity include the Fynbos, Succulent Karoo and Desert biomes; the latter showing 6–20 times more species per unit area than other biomes. Our results conform with global species‐area patterns: areas of higher‐than‐expected bee density are largely concentrated in Mediterranean and arid habitats.This study further enhances our knowledge in identifying regional and global hotspots of richness and endemism for a keystone group of insects and enabling these to be accounted for when setting conservation priorities. [ABSTRACT FROM AUTHOR]

We describe the male of Rediviva steineri Kuhlmann, 2012; distinguished by the shape and the margin of the apical plate of the eighth sterna and the vestiture of metasomal terga two and three. Five males were collected at the type locality of the female (Farm Doornbosch, Western Cape, South Africa). We examined the types of three other closely related species (R. pallidula, R. brunnea and R. whiteheadi) and provide images of the eighth sterna for comparison with R. steineri and update Whitehead et al.’s (2008) identification key for the males of these species. [ABSTRACT FROM AUTHOR]

Exaggerated traits of pollinators have fascinated biologists for centuries. To understand their evolution, and their role in coevolutionary relationships, an essential first step is to understand how traits scale allometrically with body size, which may reveal underlying developmental constraints. Few pollination studies have examined how traits can adaptively diverge despite allometric constraints. Here, we present a comparative study of narrow‐sense static and evolutionary allometry on foreleg length and body size of oil‐collecting bees. Concurrently, we assess the relationship between scaling parameters and spur lengths of oil‐secreting host flowers. Across species and populations, we found low variation in static slopes (nearly all <1), possibly related to stabilizing selection, but the static intercept varied substantially generating an evolutionary allometry steeper than static allometry. Variation in static intercepts was explained by changes in body size (∼28% species; ∼68% populations) and spur length (remaining variance: ∼36% species; ∼94% populations). The intercept–spur length relationship on the arithmetic scale was positive but forelegs did not track spur length perfectly in a one‐to‐one relationship. Overall, our study provides new insights on how phenotypic evolution in the forelegs of oil‐collecting bees is related to the variability of the allometric intercept and adaptation to host plants. [ABSTRACT FROM AUTHOR]

An appreciation of body size allometry is central for understanding insect pollination ecology. A recent model utilises allometric coefficients for five of the seven extant bee families (Apoidea: Anthophila) to include crucial but difficult-to-measure traits, such as proboscis length, in ecological and evolutionary studies. Melittidae were not included although they are important pollinators in South Africa where they comprise an especially rich and morphologically diverse fauna. We measured intertegular distance (correlated with body size) and proboscis length of 179 specimens of 11 species from three genera of Melittidae. With the inclusion of Melittidae, we tested the between family differences in the allometric scaling coefficients. AIC model selection was used to establish which factors provide the best estimate of proboscis length. We explored a hypothesis that has been proposed in the literature, but which has not been tested, whereby body and range sizes of bees are correlated with rainfall regions. We tested this by using body size measurements of 2109 museum specimens from 56 species of Melittidae and applied the model coefficients to estimate proboscis length and foraging distance. Our results from testing differences across bee families show that with the addition of Melittidae, we retained the overall pattern of significant differences in the scaling coefficient among Apoidea, with our model explaining 98% of the variance in species-level means for proboscis length. When testing the relationship between body size and rainfall region we found no relationship for South African Melittidae. Overall, this study has added allometric scaling coefficients for an important bee family and shown the applicability of using these coefficients when linked with museum specimens to test ecological hypothesis. [ABSTRACT FROM AUTHOR]

Insect pollinators, both managed and wild, have become a focus of global scientific, political and media attention because of their apparent decline and the perceived impact of this decline on crop production. Crop pollination by insects is an essential ecosystem service that increases the yield and quality of approximately 35% of crops worldwide. Pollinator declines are a consequence of multiple environmental pressures, e.g. habitat transformation and fragmentation, loss of floral resources, pesticides, pests and diseases, and climate change. Similar environmental pressures are faced in South Africa where there is a high demand for pollination services. In this paper, we synthesise data on the importance of different pollinators as a basis for services to South African crops and on the status of managed honeybees. We also focus on insect pollination services for the Western Cape deciduous fruit industry, which is worth ZAR9800 million per year and is heavily reliant on pollination services from managed honeybees. We discuss landscape and regional level floral resources needed to maintain sufficient numbers of managed honeybee colonies. In summary, the available literature shows a lack of data on diversity and abundance of crop pollinators, and a lack of longterm data to assess declines. We highlight key areas that require research in South Africa and emphasise the critical role of floral resource availability at the landscape and regional scale to sustain pollinators. We conclude that understanding the dynamics of how floral resources are used will help inform how landscapes could be better managed in order to provide long-term sustainable pollination services. [ABSTRACT FROM AUTHOR]

Wild bees are threatened by multiple interacting stressors, such as habitat loss, land use change, parasites, and pathogens. However, vineyards with vegetated inter‐rows can offer high floral resources within viticultural landscapes and provide foraging and nesting habitats for wild bees. Here, we assess how vineyard management regimes (organic vs. conventional; inter‐row vegetation management) and landscape composition determine the inter‐row plant and wild bee assemblages, as well as how these variables relate to functional traits in 24 Austrian and 10 South African vineyards. Vineyards had either permanent vegetation cover in untilled inter‐rows or temporary vegetation cover in infrequently tilled inter‐rows. Proportion of seminatural habitats (e.g., fallows, grassland, field margins) and woody structures (e.g., woodlots, single trees, tree rows) were used as proxies for landscape composition and mapped within 500‐m radius around the study vineyards. Organic vineyard management increased functional richness (FRic) of wild bees and flowering plants, with woody structures marginally increasing species richness and FRic of wild bees. Wild bee and floral traits were differently associated across the countries. In Austria, several bee traits (e.g., lecty, pollen collection type, proboscis length) were associated with flower color and symmetry, while in South African vineyards, only bees' proboscis length was positively correlated with floral traits characteristic of Asteraceae flowers (e.g., ray–disk morphology, yellow colors). Solitary bee species in Austria benefitted from infrequent tillage, while ground nesting species preferred inter‐rows with undisturbed soils. Higher proportions of woody structures in surrounding landscapes resulted in less solitary and corbiculate bees in Austria, but more aboveground nesting species in South Africa. In both countries, associations between FRic of wild bees and flowering plants were positive both in organic and in conventional vineyards. We recommend the use of diverse cover crop seed mixtures to enhance plant flowering diversity in inter‐rows, to increase wild bee richness in viticultural landscapes. [ABSTRACT FROM AUTHOR]

Simple Summary: Flies with a particularly long proboscis are characteristic of flower-visiting insects in the Greater Cape Floristic Region of South Africa. We studied an endemic nemestrinid fly species in a small isolated area of semi-natural vegetation where these insects were the only flower visitors that could drink nectar from the available long-tubed flowers of one plant species. We examined the mouthpart structures that are important for nectar uptake and the length and diameter of the proboscis in comparison with the flower sizes. This local one-to-one interaction between the fly population and its nectar host flower gave the opportunity to quantify the nectar resources available for the nemestrinid flies at the study site. By comparing the offered nectar volumes before and after flower visits, the average meal size could be estimated. Assessments of the nectar levels from measured quantities and flower size allowed us to make predictions of how various proboscis lengths could reach nectar inside floral tubes. Several Prosoeca (Nemestinidae) species use a greatly elongated proboscis to drink nectar from long-tubed flowers. We studied morphological adaptations for nectar uptake of Prosoecamarinusi that were endemic to the Northern Cape of South Africa. Our study site was a small isolated area of semi-natural habitat, where the long-tubed flowers of Babiana vanzijliae (Iridaceae) were the only nectar source of P. marinusi, and these flies were the only insects with matching proboscis. On average, the proboscis measured 32.63 ± 2.93 mm in length and less than 0.5 mm in diameter. The short labella at the tip are equipped with pseudotracheae that open at the apical margin, indicating that nectar is extracted out of the floral tube with closed labella. To quantify the available nectar resources, measurements of the nectar volume were taken before the flies were active and after observed flower visits. On average, an individual fly took up approximately 1 µL of nectar per flower visit. The measured nectar quantities and the flower geometry allowed estimations of the nectar heights and predictions of necessary proboscis lengths to access nectar in a range of flower tube lengths. [ABSTRACT FROM AUTHOR]