Fig 1.
Volume composition and quality of seasonal pollen mixes harvested in an agricultural landscape of western France (46 ° 09′ 13″ N; 0° 41′ 20″ W).
Protein and lipid levels, and Shannon Weaver index were calculated for each mix. Pollen protein and lipid are expressed as % of dry matter. Name of species written in red are the main crop species, in blue the fodder species, and in black the wild flowers species.
Fig 2.
Effect of pollen depletion on worker survival.
Data show the percentages of surviving workers over 60 days (n = 10 cohorts per treatment) according to the amount of pollen available (by weight in %). Different letters denote significant differences (p < 0.001, Cox proportional hazards regression model).
Fig 3.
Effects of oilseed rape pollen depletion on (A) the diameter of hypopharyngeal gland acini and (B) vitellogenin expression levels, in honey bees.
Box plots are shown for 30 workers (acini) and 10 pools of 3 bees (vitellogenin) for each diet treatment. Different letters indicate significant differences between pollen quantities (p < 0.001, Wilcoxon tests with Bonferroni correction for HPGs and Tukey post-hoc tests for vitellogenin expression levels, respectively). Boxes show 25th and 75th percentiles range with the line denoting the median. Whiskers encompass 90% of the individuals, beyond which outliers are represented by dots.
Table 1.
Pesticide residues in the seasonal pollen mixes.
Fig 4.
Amounts of the different pollen mixes consumed per bees.
Box plots are shown for 10 cages per treatment. Different letters indicate significant differences between the amounts of pollen consumed (p < 0.001, Wilcoxon test with Bonferroni correction). Boxes show 25th and 75th percentiles range with line denoting the median. Whiskers encompass 90% of the individuals, beyond which outliers are represented by dots.
Fig 5.
Influence of different seasonal pollen mixes on bee survival.
Data show the percentages of surviving workers over 90 days (n = 10 repetitions per treatment). Different letters denote significant differences (p < 0.001, Cox proportional hazards regression model).
Fig 6.
Influence of different seasonal pollen mixes on (A) the diameter of hypopharyngeal gland acini and (B) the vitellogenin expression levels, in honey bee workers.
Box plots are shown for 30 bees (acini) and 10 pools of 3 bees (vitellogenin) per diet treatment. Different letters indicate significant differences between pollen quantities (p < 0.001 based upon Wilcoxon tests with the Bonferroni correction for HPGs and Tukey post-hoc tests for vitellogenin expression levels). Boxes show 25th and 75th percentiles range with the line denoting median. Whiskers encompass 90% of the individuals, beyond which outliers are represented by dots.