1998

1999

2000

2001

2002

2003 ³

Number of nests

19.4±6.1
(0–159)

26.9±5.7
(0–127)

117.2±26
(0–708)

229.6±51.4
(1–903)

720.4±166
(4–3790)

18.5±2.9
(0–60)

Number of brood cells

78.6±20.3
(0–418)

126.6±22.3
(0–521)

518.5±110.7
(0–2909)

1009±225
(3–4356)

2741±627
(4–14734)

80.9±13.7
(0–283)

Brood cells per nest

4.74±0.29
(2.33–7.0)

5.28±0.17
(2.76–7.33)

4.31±0.18
(1.75–6.03)

4.22±0.12
(2.4–5.59)

3.77±0.14
(1.0–4.95)

4.53±0.31
(1.0–10.0)

Parasitism (%) ¹

27.4±4.7
(0–80)

20.6±3.2
(0–53.2)

20.7±2.8
(2.8–52.1)

28.7±2.8
(4.1–58.1)

12.9±1.3
(2.9–25.8)

31.7±3.3
(6.6–64.7)

Larval mortality (%) ¹

19.6±2.4
(0–52.9)

13.2±2.6
(0–54.5)

14.7±1.1
(3.8–28.3)

14.9±2.1
(4.1–58.3)

11.8±1.0
(1.4–21.9)

28.3±2.4
(7–57.5)

Pupal mortality (%) ¹

27.9±4.8
(0–92.8)

8.8±3.7
(0–82.6)

8.9±1.2
(1.2–23.9)

5.4±2.1
(0–59.9)

-

-

Occupied reed stems (%) ²

1.22±0.5
(0–14.36)

1.46±0.3
(0–6.69)

6.01±1.22
(0–31.97)

10.11±2.15
(0.05–38.05)

25.91±4.99
(0.21–95.83)

0.98±0.16
(0–3.16)

O. rufa
(% brood cells)

35.8

52.7

69.4

78.7

84.8

21.7

Other bees
(% brood cells)

11.3

6.9

5.6

5.9

4.0

27

Wasps
(% brood cells)

52.9

40.4

25

15.4

11.2

51.3