Foraging efficiency and size matching in a plant–pollinator community: the importance of sugar content and tongue length

Abstract

A long‐standing question in ecology is how species interactions are structured within communities. Although evolutionary theory predicts close size matching between floral nectar tube depth and pollinator proboscis length of interacting species, such size matching has seldom been shown and explained in multispecies assemblages. Here, we investigated the degree of size matching among Asteraceae and their pollinators and its relationship with foraging efficiency. The majority of pollinators, especially Hymenoptera, choose plant species on which they had high foraging efficiencies. When proboscides were shorter than nectar tubes, foraging efficiency rapidly decreased because of increased handling time. When proboscides were longer than nectar tubes, a decreased nectar reward rather than an increased handling time made shallow flowers more inefficient to visit. Altogether, this led to close size matching. Overall, our results show the importance of nectar reward and handling time as drivers of plant–pollinator network structure.

Sex differences in pollinator behavior: Patterns across species and consequences for the mutualism

“…Bronstein and G. Davidowitz, unpublished data). Even if the visitor can access nectar, morphological mismatches between flower and visitor may reduce the efficiency of foraging (Klumpers, Stang, & Klinkhamer, 2019). Even if the visitor can access nectar, morphological mismatches between flower and visitor may reduce the efficiency of foraging (Klumpers, Stang, & Klinkhamer, 2019).…”

“…As many flowers have nectar spurs, deep corollas, or other structures that restrict access to the rewards they offer based on morphology, a pollinator's size and in particular the length of its mouthparts can determine which flowers are successfully visited, the pollination services provided to the plant, and the handling efficiency of the pollinator (Nilsson, 1988). Even if the visitor can access nectar, morphological mismatches between flower and visitor may reduce the efficiency of foraging (Klumpers, Stang, & Klinkhamer, 2019). It will also potentially reduce the quality of pollen transfer, as it will affect the likelihood that the same part of the pollinator's body contacts both the anthers and the stigma.…”

Geographic variation of reproductive traits and competition for pollinators in a bird‐pollinated plant

“…As a consequence, individuals in populations with smaller plants may be visited less frequently. Several studies have found that plant phenotype is highly predictive of pollination visitation networks (Biddick & Burns, ; Klumpers, Stang, & Klinkhamer, ). For example, Biddick and Burns () demonstrated that plant species with large flowers received higher visitation rates from birds than plants with smaller flowers.…”

“…As a consequence, individuals in populations with smaller plants may be visited less frequently. Several studies have found that plant phenotype is highly predictive of pollination visitation networks Klumpers, Stang, & Klinkhamer, 2019 Another plausible explanation for geographic variation in B. ringens phenotype is that it is driven by features of the abiotic environment, either as plastic responses or as evolved responses to local conditions. However, we found no relations between the most limiting resources (N, P, rainfall) in the Cape (see Cramer, West, Power, Skelton, & Stock, 2014) and perch size.…”

Fiber‐optic refractometer for in vivo sugar concentration measurements of low‐nectar‐producing flowers

“…Interest in flower nectar production is currently increasing and research is aimed at achieving very diverse goals: these include the evolution of plantpollinator interactions (e.g. Nepi et al, 2008;Klumpers et al, 2019;Parachnowitsch et al, 2019), predictive effects of climate changes (e.g. Phillips et al, 2018;Takkis et al, 2018), conservation of endangered species (e.g.…”