Pollinator visitation closely tracks diurnal patterns in pollen release

Abstract

Premise: Animal-pollinated plants face a high risk of pollen loss during its transfer. To limit the negative effect of pollen losses by pollen consumption and heterospecific transfer, plant species may adjust and stratify their pollen availability during the day (i.e., "schedule" their pollen presentation) and attract pollinators in specific time frames. Methods: We investigated diurnal patterns of pollen availability and pollinator visitation in three coflowering plant species: Succisa pratensis with open flowers and accessible pollen, pollinated mainly by pollen-feeding hoverflies; Centaurea jacea with open flowers and less accessible pollen, pollinated mainly by pollen-collecting bees; and Trifolium hybridum with closed flowers and pollen accessible only after the active opening of the flower, pollinated exclusively by bees. Results: The three plant species differed in the peak pollen availability, tracked by the visitation activity of their pollinators. Succisa pratensis released all pollen in the morning, while pollinator activity was still low and peaked with a slight delay. In contrast, C. jacea and T. hybridum had distinct pollen presentation schedules, peaking in the early afternoon. The pollinator visitation to both of these species closely matched their pollen availability. Conclusions: Stratifying pollen availability to pollinators during the day may be one of several mechanisms that allow coflowering plants to share their pollinators and decrease the probability of heterospecific pollen transfer.

Heterospecific pollen avoidance strategy prevails in the generalized plant–pollinator network on Yongxing Island

“…Interspecific separation of the sites of pollen assignment and stigma contact on the pollinator body can also reduce the HP load on the stigmas (Huang et al., 2015 ; Huang & Shi, 2013 ; Johnson, 2010 ). Co‐flowering plants that share pollinators can reduce the possibility of HP transfer by stratifying pollen availability to pollinators during the daytime (Štenc et al., 2023 ). In the Yongxing Island community, the half‐day staggered flowering between morning and afternoon might reduce the number of co‐flowering plant species and thus decrease the probability of HP transfer (Wang et al., 2021 ).…”

The pollen virome: A review of pollen‐associated viruses and consequences for plants and their interactions with pollinators

“…Indeed, generalist plants encounter a greater diversity and abundance of heterospecific pollen than specialist plants (Arceo‐Gómez et al, 2016; Wei et al, 2022). Plant traits such as large multiflowered inflorescences with relatively larger amounts of pollen (Ohara and Higashi, 1994; Koski et al, 2015; Leme da Cunha, Aizen, 2023; Rodríguez‐Otero et al, 2023) and/or long‐lived flowers that bloom and present pollen throughout the height of pollinator activity (McArt et al, 2014; Štenc et al, 2023) increase the likelihood of attracting a variety of pollinators. Recently, Fetters et al (2022) found more viral taxa in association with pollen collected from wild plant species with multiflowered inflorescences rather than single flowers.…”