Co‐flowering neighbors influence the diversity and identity of pollinator groups visiting plant species

Abstract

The generalization–specialization continuum exhibited in pollination interactions currently receives much attention. It is well‐known that the pollinator assemblage of particular species varies temporally and spatially, and therefore the ecological generalization on pollinators may be a contextual attribute. However, the factors causing such variation and its ecological and evolutionary consequences are still poorly understood. This variation can be caused by spatial or temporal variation in the pollinator community, but also by variation in the plant community. Here, we examined how the floral neighbourhood influenced the generalization on pollinators and the composition of pollinators of six plant species differing in generalization levels and main pollinators. The diversity, identity and density of floral species affected both the level of generalization on pollinators and the composition of visitors of particular plant species. Although the relationships to floral neighbourhood varied considerably among species, generalization level and visitation by uncommon pollinators generally increased with floral diversity and richness. The generalization level of the neighbourhood was negatively related to the generalization level of the focal species in two species. The number of flowers of the pollinator‐sharing species and the number of flowers of the focal species had different effects on the composition of visits in different species; attributable to differences in facilitation/competition for pollinator attraction. We propose that an important ecological implication of our results is that variation in species interactions caused by the pollination context may result in increased community stability. The main evolutionary implication of our results is that selection on flower and pollinator traits may depend, to an unknown extent, on the composition of the co‐flowering plant community.

Temporal stability of pollinator preference in an alpine plant community and its implications for the evolution of floral traits

“…For example, shape preferences of butterflies, honeybees and beeflies varied across years, such that in 2007 open flowers did not show a higher level of ecological generalization than closed flowers. This result may be due to variation in the structure of the community (McCall and Primack 1992; Hingston and McQuillan 2000;Ollerton et al 2007;Lázaro et al 2008Lázaro et al , 2009). …”

“…2). This non-significant result in 1 year could be because the realized pollinator generalization level was influenced not only by floral traits but also by community structure (both composition and abundance of plants and pollinators) (McCall and Primack 1992;Hingston and McQuillan 2000;Ollerton et al 2007;Lázaro et al 2008Lázaro et al , 2009). Lázaro et al (2008) demonstrated that closed flowers were more generalized than open flowers in one of three Scandinavian plant communities because of the variation in composition of the pollinator assemblage.…”

“…For example, three of the most abundant plant species (three Pedicularis species), which are also the most specialized closed flowers, were not flowering in 2007, which may have led to the increase of overall generalization level of closed flowers. Similarly, a recent study conducted by Lázaro et al (2009) demonstrated that the ecological generalization on pollinators can be influenced by variation in the diversity, identity and density of co-flowering neighbors.…”

Plant–pollinator interactions between an invasive and native plant vary between sites with different flowering phenology

“…Sites were analyzed separately and responses compared using t tests or z tests ( Feinsinger 1987;Ghazoul 2006;Rathcke 1983). Plant density and diversity affect both the composition and abundance of pollinators on plants (Conner and Neumeier 1995;Hegland and Totland 2005;Lazaro et al 2009;Moeller 2005), consistent with the idea that L. maackii affected the composition and abundance of pollinators on H. macrophyllum. Data from our pollinator observations suggest that L. maackii attracted to the plots a variety of pollinator species that also visited H. macrophyllum; we found more pollinator taxa on H. macrophyllum in plots in which L. maackii was present.…”

Restabelecimento das interações entre plantas e visitantes florais em áreas restauradas de floresta estacional semidecidual

“…De qualquer maneira, a similaridade na composição destas comunidades é baixa: cinquenta e sete das espécies vegetais floridas foram de ocorrência exclusiva de alguma das áreas, sendo RD3 e RA3 as áreas com maior número de ocorrências exclusivas (19 e 14 respectivamente), seguidas de RA1 (11), (Lázaro et al 2009). …”