Data from: Exotic flower visitors exploit large floral trait spaces resulting in asymmetric resource partitioning with native visitors

1.Exotic species often cause severe alterations in native communities due
to their ability to rapidly and efficiently utilize a broad spectrum of
resources. In flower-visitor interactions, the breadth of resource use by
native and exotic animals as well as the partitioning of resources among
them is often estimated based on the number of (shared) plant species used
as resources. However, whether a flower visitor is able to exploit plant
resources has been shown to be delimited by functional floral traits such
as morphological barriers or attractive or repellent chemical cues. Each
of the ecologically relevant traits can be viewed as a dimension of a
Hutchinsonian n-dimensional hypervolume, which characterizes the range of
phenotypes exploitable by a species. 2.In this study, we quantified the
sizes and overlaps of n-dimensional hypervolumes defined by floral traits
that are exploitable by native and exotic flower visitors (afterwards
referred to as exploited space, ES). In the heavily invaded Hawai'i
Volcanoes National Park, USA, we phenotyped 40 native and exotic plant
species and recorded flower-visitor interactions. To quantify the size and
overlap of ES, we applied dynamic range boxes (dynRB). 3.On average,
exotic flower visitors were more generalized in resource use (larger ES)
than natives ones, which is additionally indicated by the absence of
native flower visitors on exotic flowering plant species. In particular,
ES based on floral scent emission was larger for exotic flower visitors
compared to native ones. The unevenly expanded ES of native and exotic
animals led to an asymmetric overlap of floral ES where the exotic flower
visitors shared only a small proportion of their ES with natives but
occupied a large proportion of the ES of natives. 4.The asymmetry in
resource use of native and exotic flower visitors suggests a potential
advantage in resource exploitation of the latter, potentially explaining
their success in Hawaiian ecosystems. Predicted range expansion of exotic
plant and animal species may further increase the competition for and
reduce the availability of resources for native animals. This may lead to
further declines of native species and increasing threats for Hawaiian
ecosystems.