Table 2 Concentrations of active substances [ng/g] detected in provisions collected by Osmia bicornis bees as food for their larvae in twelve nests located in the agricultural landscape.

From: Floral resources,energetic value and pesticide residues in provisions collected by Osmia bicornis along a gradient of oilseed rape coverage

Active substance

Typea

Concentrations of active substances [ng/g] detected in provisions in different nests

LOQ [ng/g]b

Number of nests detected

Percent of nests detected [%]

Min [ng/g]c

Max [ng/g]c

Median [ng/g]

Oral 48-h LD50 for honeybee [µg/bee]d

A1

A2

A3

A4

A5

A6

A7

A8

A9

A10

A11

A12

Acetamiprid

I

–

0.37

–

0.83

–

0.28

0.33

0.12

0.11

1.16

0.11

0.22

0.10

9

75.00

0.11

1.16

0.28

14.53

Azoxystrobin

F

–

22.55

10.60

–

–

8.95

5.50

8.90

12.00

198.40

–

–

1.00

7

58.30

5.50

198.40

10.60

> 25.00

Boscalid

F

15.45

10.20

15.75

–

16.95

11.25

–

–

–

–

7.90

5.90

0.01

7

58.30

5.90

16.95

11.25

100.00

Chlorothalonil

F

–

–

–

–

–

2.15

–

–

–

–

–

–

1.00

1

8.30

2.15

2.15

–

> 40.00

Difenoconazole

F

–

–

–

–

–

–

6.55

–

–

40.30

–

–

0.01

2

16.70

6.55

40.30

23.43

> 177.00

Fluopyram

F, N

–

4.93

–

41.10

–

2.88

12.23

–

–

–

10.03

2.08

1.00

6

50.00

2.08

41.10

7.48

> 102.30

Fluxapyroxad

F

–

2.05

–

–

–

2.75

–

–

–

–

2.40

6.55

1.00

4

33.30

2.05

6.55

2.58

> 110.90

Picoxystrobin

F

3.70

–

–

–

–

–

–

–

–

–

–

–

0.10

1

8.30

3.70

3.70

–

> 200.00

Tebuconazole

F

24.35

–

16.20

–

–

–

10.45

18.55

–

6.30

–

–

1.00

5

41.70

6.30

24.35

16.20

> 83.05

Dimethoate

I, A

–

2.75

–

12.05

–

7.85

4.35

17.08

–

–

1.70

3.00

1.00

7

58.30

1.70

17.08

4.35

0.10

Omethoate

I, A

–

1.13

–

6.33

–

4.98

1.40

9.13

–

–

–

1.33

5.00

6

50.00

1.13

9.13

3.19

0.05

Prosulfocarb

H

–

–

–

–

–

26.40

–

–

–

–

–

–

1.00

1

8.30

26.40

26.40

–

103.40

Provision mass [mg]e

 

246.50

241.80

239.80

233.20

252.20

216.30

238.90

241.30

212.20

254.30

229.50

231.90

       

Pesticide Risk Indexf

 

0.01 × 10–3

1.26 × 10–3

0.02 × 10–3

5.89 × 10–3

0.004 × 10–3

3.96 × 10–3

1.75 × 10–3

8.72 × 10–3

0.01 × 10–3

0.21 × 10–3

0.40 × 10–3

1.34 × 10–3

       
  1. Twelve active substances were detected above their limits of quantification (LOQb), including 8 fungicides, 3 insecticides and 1 herbicide, and were used to calculate pesticide risk index with toxic unit (TU) approach based on 48-h LD50 values for orally exposed adult honeybee; ‘– ‘ means not detected.
  2. aI—Insecticide, H—Herbicide, F—Fungicide, N—Nematicide, A—Acaricide.
  3. bLOQ values for the 510 active substances tested can be found in Table S7 of the Supplementary materials in Bednarska et al.26. Four concentrations of omethoate were detected below the LOQ.
  4. cMin and max given for detected active substance.
  5. dBecause neither larval nor adult LD50 values specific to Osmia sp. were available, the oral acute 48-h LD50 values for adult honeybees were used to calculate pesticide Risk Index. Oral acute 48-h LD50 values for adult honeybees available from the Pesticide Properties Database (https://sitem.herts.ac.uk/aeru/ppdb/en/Reports/321.htm).
  6. eProvision mass expressed as the average provision mass in the nest calculated based on data for the two types of cells: the most inner cells in the nesting cavities (i.e., those in which females would most likely develop) and the outermost cells located at the posterior end of the nesting cavity (i.e., those in which males would most likely develop) (data not published).
  7. fPesticide Risk Index calculated for all detected active substances based on oral acute 48-h LD50 values for adult honeybee using Toxic Unit approach. To overcome the problem that in several cases the value for oral 48-h LD50 was expressed as > x, we used exactly the x value which is a conservative approach.
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