Fig. 2a–i.

Species compositions (w/w) of honeybee pollen pellets collected at Shibetsu City, northern Hokkaido. Proportions of minor species (< 5%), shown as “others” in the plots, were as follows: a Tilia sp. (3.8%), Actinidia polygama (3.0%), Hydrangea petiolaris (2.5%), Hydrangea paniculata (2.1%), Hypochaeris radicata (1.7%), Parasenecio sp. (0.8%); b H. petiolaris (2.8%), Parasenecio sp. (2.7%), H. paniculata (1.9%), H. radicata (1.5%); c Rudbeckia laciniata (3.6%), Parasenecio sp. (2.6%), Sinapis alba (1.2%); d Fagopyrum esculentum (3.9%), H. radicata (3.5%); e Trifolium pratense (2.2%), Parasenecio sp. (1.6%), Trifolium repens (1.4%), Chenopodium album (1.3%), Commelina communis (1.2%), unidentified (1.3%); f T. pratense (1.6%), Solidago gigantea (1.6%); g S. gigantea (4.2%); h Solidago virgaurea (3.8%), C. communis (1.9%); i Artemisia montana (4.2%), S. virgaurea (3.5%), Solanum nigrum (2.3%), T. pratense (1.6%), T. repens (1.1%)