Figure 5. Relation between habitat structure and mean body length of bee species and the mean foraging trip duration: (a) Foraging trip duration of *O. rufa* in different habitat types anova: *F* = 2·89, *n* = 41, *P* = 0·048. (b) Foraging trip duration of *O. rufa* in relation ▪ to the number of plant species. Linear regression model: *y* = 1118–7·14 *x*, *F* = 9·88, *r*^{2} = 59%, *n* = 7, *P* = 0·026. Field type symbols: set-aside fields sown with grass–clover mixture, • field margin strips, extensively used grassland, ◆ chalk grassland. (c) Foraging trip duration in relation to the mean body length of eight solitary bee species. Linear regression model: *y* = −1395 + 244·8*x*, *r*^{2} = 56%, *F* = 7·77, *n* = 7, *P* = 0·032. (d) Foraging trip duration for different solitary bee species. Species on the *x*-axis were sorted by their mean body length (left small, right large). anova: *F* = 18·1, *n* = 72, *P* < 0·001. Species abbreviations: H.t., *H. truncorum*; C.r., *C. rapunculi*; O.l., *O. leucomelana*; O.p., *O. parietina*; O.r., *O. rufa*; O.le., *O. leaiana*; M.l., *M. lapponica*; M.v., *M. versicolor*. In Fig. 5a and d, arithmetic means and standard errors are given. Identical letters show homogeneous groups (Tukey test).

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