The corbicula or pollen basket plays a central role in pollen collection in honey bees and stingless bees, and thus can be applied to study floral resource use by foraging bees. We investigated corbicular pollen load composition and foraging activity of sympatric honey bees (Apis cerana) and stingless bees (Geniotrigona thoracica and Heterotrigona itama) in a beekeeping area in North Sumatra, Indonesia. A total of 44 corbicular pollen loads were collected from the three bee species (two colonies per species). Pollen samples were processed using the acetolysis method and identified based on morphology. Pollen types were quantified by relative abundance and differences among species were evaluated using diversity indices and multivariate analyses based on Bray-Curtis dissimilarity. Vegetation surveys were conducted to assess floral resource availability and their relationship with pollen composition. Foraging activity was observed over three consecutive days and analyzed in relation to environmental factors, with temporal overlap assessed using overlap indices. Pollen composition differed among species, with stingless bees showing higher pollen diversity than A. cerana, particularly in H. itama compared to G. thoracica. Multivariate analyses revealed significant but weakly separated pollen composition, indicating partial overlap in pollen use among the three bee species, with Cocos nucifera as a shared key floral resource. Despite the availability of flowering plants, pollen composition reflected selective rather than proportional use of available floral resources. Differences in pollen composition were associated with distinct pollen-foraging timing influenced by environmental factors. Apis cerana exhibited higher pollen-collecting activity in the morning that declined toward midday, whereas stingless bees maintained relatively consistent activity throughout the day. Temporal overlap analysis indicated partial separation in foraging activity, suggesting temporal resource partitioning between honey bees and stingless bees. These findings highlight the importance of maintaining diverse and continuous floral resources to support coexistence in sympatric managed bee communities.
This study presents the micromorphology and taxonomic significance of the pollen and seeds of members of the genus Thymbra in T & uuml;rkiye. Pollen and seed samples were analyzed using light and scanning electron microscopy, and quantitative measurements were recorded. Multivariate statistical analyses, including principal component analysis (PCA) and cluster analysis, were applied to assess variation and relationships among the taxa. Pollen grains were hexacolpate, mostly suboblate in equatorial view and hexagonal in polar view, with a bi-reticulate exine pattern. The polar axis (P) ranged from 25.31 to 32.45 mu m, and the equatorial axis (E) ranged from 32.25 to 39.04 mu m. Seed surface and size also varied among taxa, providing additional diagnostic traits. PCA and cluster analyses showed that pollen micromorphological traits effectively distinguish the five taxa, highlighting their taxonomic significance. Thymbra capitata, T. spicata, and T. sintenisii formed distinct groups, primarily influenced by P, E, amb (E1 and E2) and colpus measurements (Clg and Clt). Intine thickness, P/E ratio, lumina diameter, and reticula diameter were effective characters for differentiation, particularly enhancing discrimination at the subspecies level. The results obtained in this study are consistent with the most recent revision of the studied taxa. This study represents the first comprehensive pollen and seed morphology of Thymbra taxa in T & uuml;rkiye, offering valuable data for species identification and classification within the genus.
The Elandsfontyn Formation at Langebaanweg in southwestern South Africa preserves an Oligocene-Miocene palaeo-record that offers key insights into the evolution of the Fynbos Biome. To clarify the timing and drivers of vegetation change, including sea-level fluctuations and climate, we reassessed the palynology of core BH2. Traditional palynological methods were applied to 77 samples, yielding 104 palynomorph taxa, including pollen, spores, and dinoflagellate cysts. Results confirm humid, warm-temperate to subtropical forests dominated by Podocarpaceae, palms, vines, and ferns, while mangroves indicate warm sea-surface temperatures. Patches of proto-fynbos, represented by Ericaceae and Proteaceae, likely formed part of the forest understorey or margins and fluctuated alongside forest elements. As forests retreated, wetlands with Sparganiaceae, Restionaceae, Cyperaceae, and Poaceae expanded. Marine incursions linked to global Late Oligocene-Miocene sea-level change affected the coastline, with three transgressions (I-III) recognized. These correlate with global events occurring between 27.82 Ma (Late Oligocene) and 17.8 Ma (Early Miocene). Increasing sea levels and aridity gradually replaced forests with woodlands containing Combretaceae, Peregrinipollis nigericus (Brachystegia), proto-fynbos, and nearby Restionaceae-dominated wetlands. Continued Transgression II likely caused the retreat of this woodland, while persistently high sea levels during Transgression III may have promoted the emergence of the Fynbos Biome. A strongly fluctuating micro-charcoal record suggests shifting fire regimes, probably driven by changing seasonality and local moisture conditions. Quantitative palaeoclimate reconstruction using Nearest Living Relative (NLR) methods remains limited by uncertain botanical affinities and conflicting signals between taxa indicating winter- versus summer-rainfall climates.
