Morphological trait matching in plant–Hymenoptera and plant–Diptera mutualisms across an elevational gradient

Morphological trait-matching and species abundance are thought to be the main factors affecting the frequency and strength of mutualistic interactions. However, the relative importance of trait-matching and species abundance in shaping species interactions across environmental gradients remains poorly understood, especially for plant–insect mutualisms involving generalist species.

Here, we characterised variation in species and trait composition and the relative importance of trait-matching and species abundance in shaping plant–Hymenoptera and plant–Diptera mutualisms in four meadows across an elevational gradient (2,725–3,910 m) in Yulong Snow Mountain, Southwest China. We also evaluated the effects of morphological traits of flower visitors and plant composition on their foraging specialisation (d’ and normalised degree).

There was a high degree of dissimilarity in the composition of Hymenoptera and Diptera visitors and their visited plants between communities. This variation w...