Data from: Influence of the honeybee and trait similarity on the effect of a non-native plant on pollination and network rewiring

Introduced entomophilous non-native plants usually become well integrated
into the diet of generalist pollinators. This integration can affect the
entire recipient plant–pollinator network. Effects vary from facilitative
to competitive, and understanding the factors that govern such variability
is one of the fundamental goals in invasion ecology. Species traits
determine the linking patterns between plant and pollinator species.
Therefore, trait similarity among plants or among pollinators might
modulate how they affect each other. We conducted a flower removal
experiment to investigate the effects of the non-native entomophilous
legume Hedysarum coronarium on the pollination patterns of a Mediterranean
shrubland plant–pollinator network. Specifically, we explored whether
effects were influenced by similarity with the resident plant species in
flower morphology (papilionate vs. non-papilionate), and whether effects
on the pollinator community were influenced by similarity in functional
group with its main visitor species (bees vs. non-bees). In addition, we
explored whether Hedysarum had an effect on the identity of interactions.
For this purpose, we calculated the interaction rewiring, that is the
number of plant–pollinator interactions that were gained or lost after
invasion. Hedysarum was well integrated into the diet of 15 generalist
pollinators having the honeybee as its main visitor species. Such
integration did not affect visitation rates, normalized degree (i.e.
proportion of pollinators they are visited by) nor niche overlap (i.e.
proportion of plant species they share pollinators with) of plants,
irrespective of their flower morphology. Only the proportion of honeybee
visits to resident plants decreased with invasion. On the other hand,
Hedysarum reduced visitation rates and niche overlap of pollinators,
mainly those of bee species. Finally, we observed that changes in the
foraging behaviour of the honeybee were positively associated with the
interaction rewiring involving the rest (92 taxa) of pollinators. In
conclusion, pollinators show a plastic use of floral resources, responding
to the presence of non-native plants. When the non-native attracts highly
competitive pollinators such as the honeybee, plasticity is especially
significant in pollinators that are functionally close to that competitive
pollinator. The result is an interaction rewiring, probably due to
pollinators avoiding competition with the honeybee. Though this plasticity
might not quantitatively affect the pollination of plants, consequences on
their reproduction and the functioning of the network can derive from the
interaction rewiring.