Diversity, abundance, and pollen affinity of wild bee pollinators of almond: Insights from a Moroccan orchard
Data files
Feb 26, 2026 version files 37.51 KB
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README.md
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Suplimentary_Tables.xlsx
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Abstract
Almond trees are economically important and widely cultivated across the Mediterranean. Their yield depends on cross-pollination by insects, yet their pollinators remain largely unknown, particularly in North Africa. This study investigated the diversity, abundance, and pollen affinity of wild bee species in a Moroccan almond orchard. Using sweep netting and pan traps, a total of 813 specimens representing 104 species, 17 genera, and five families were recorded in the studied orchard. Bee diversity and abundance peaked during the flowering phase, reflecting the key role of bloom phenology in shaping pollinator activity. The most species-rich and abundant genera were Andrena, Eucera, and Lasioglossum. In total, 26 species were identified as almond floral visitors (AFV), with Andrena flavipes and Andrena bimaculata being the most abundant floral visitors. Among them, palynological data identified eight species as almond pollen victors (APV), with a total of 182 plant-bee interactions and confirmed strong almond pollen affinity for both Andrena species, particularly A. flavipes. While this study is limited to one orchard, it highlights the ecological importance of wild bees in Moroccan almond systems and underscores the potential of selecting native species to enhance pollination services, especially in light of reported pollination deficits. These findings support the development of conservation-oriented management strategies aimed at sustaining pollinator diversity and crop productivity.
Dataset DOI: 10.5061/dryad.3n5tb2rzj
Description of the data and file structure
The data presented in this repository were collected as part of a field study on wild bee communities. Sampling was conducted in an almond orchard in the Marrakech–Safi region. Data collection took place over multiple observation periods corresponding to the different flowering stages of the almond trees (pre-flowering, early flowering, peak flowering, and end of flowering), with standardized repetitions to ensure representative sampling of the species assemblages.
Files and variables
File: Suplimentary_Tables.xlsx
Description: Supplementary Tables provide information on wild bees in the almond orchard, listing all collected species and showing the flight activity periods of the 26 species identified as almond pollinators.
Variables
Table S1: Summary of statistical model outputs for the effect of bee species on the proportion of Prunus dulcis pollen.
The response variable was specified as the count of Prunus dulcis pollen grains and the count of non-P. dulcis grains among the 20 pollen grains recorded for each individual (i.e., binomial successes and failures entered as cbind(successes, failures)). The bee species was included as the predictor. The model was fitted using a binomial error distribution with a logit link. The dataset included N = 38 observations, comprising 19 Andrena bimaculata and 19 Andrena flavipes. All parameter estimates, standard errors, z statistics, and p-values correspond to this binomial model. Significance of predictors was assessed using a Type II Wald χ² test (Anova function). This table provides full transparency of the outputs of the model used to analyse the proportion of Prunus dulcis pollen among bee species:
Table S2: List of bee species collected on the almond orchard.
- Families: Taxonomic family to which the recorded organism belongs. This variable groups genera and species at the family level following standard biological classification.
- Genus: Genus name of the observed organism. This is the taxonomic rank below family and above species.
- Species: Scientific species name (binomial nomenclature) of the organism recorded during sampling.
- Flowering periods: Temporal category describing the flowering stage of the plant (almond tree) at the time of observation or sampling. This represents phenological phases (e.g., early flowering, peak flowering, late flowering).
- Plots: Identifier of the sampling unit or experimental plot where observations were conducted. Plots represent spatial replicates within the study area (orchard).
- Abundance: Total number of individuals recorded for a given taxon within the studied orchard.
- SamplingMethode: Sampling technique used to collect or observe organisms: sweepnet and pan traps.
- Sampling: represents the location where specimens are collected: Orchard for wild plant flowers and Prunus Dulcis for almond tree flowers.
Table S3: Flight activity periods of the 26 wild bee species identified as almond pollinators.
Before flowering: Period preceding the onset of flowering, during which no open flowers are present. This stage represents pre-flowering conditions.
Beginning of flowering: Early flowering stage marked by the appearance of the first open flowers. Floral resources are present but still limited compared to later stages.
Peak of flowering: Stage at which flowering intensity is maximal, with the highest density or proportion of open flowers. This period typically corresponds to maximum resource availability.
End of flowering: Late flowering stage during which flowering declines and only a small proportion of flowers remain open. This phase precedes the cessation of flowering.
File: Supplimentary_figures.docx
Description: Supplementary Figures show the orchard location and sampled plots, the flowering phases of almond trees, the sampling methods, and the total abundance and species richness of wild bees by collection method (sweep nets and colored pan traps: white, yellow, and blue).
Variables
- FIGURE S1: Map showing the location of the almond orchard and the three plots where the study was conducted
- FIGURE S2: The photos illustrate the different flowering phases of the almond tree during which the study was conducted.
- FIGURE S3: Illustration of the sampling methods applied during the survey in the orchard.
- FIGURE S4: Total abundance and species richness of wild bees by collection method: sweep net and colored pan traps (white, yellow, and blue)