Pollinator abundance, morphology, and flower visitation rate: analysis of the “quantity” component in a plant-pollinator system

Oecologia ◽  
1989 ◽  
Vol 80 (2) ◽  
pp. 241-248 ◽  
Author(s):  
Carlos M. Herrera

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e4998 ◽  
Author(s):  
Jan Klecka ◽  
Jiří Hadrava ◽  
Pavla Koloušková

Visitation of plants by different pollinators depends on individual plant traits, spatial context, and other factors. A neglected aspect of small-scale variation of plant–pollinator interactions is the role of vertical position of flowers. We conducted a series of experiments to study vertical stratification of plant–pollinator interactions in a dry grassland. We observed flower visitors on cut inflorescences ofCentaurea scabiosaandInula salicinaplaced at different heights above ground in two types of surrounding vegetation: short and tall. Even at such a small-scale, we detected significant shift in total visitation rate of inflorescences in response to their vertical position. In short vegetation, inflorescences close to the ground were visited more frequently, while in tall vegetation, inflorescences placed higher received more visits. Moreover, we found major differences in the composition of the pollinator community on flowers at different heights. In a second experiment, we measured flower visitation rate in inflorescences ofSalvia verticillataof variable height. Total flower visitation rate increased markedly with inflorescence height in this case. Data on seed set of individual plants provide evidence for a corresponding positive pollinator-mediated selection on increased inflorescence height. Overall, our results demonstrate strong vertical stratification of plant–pollinator interactions at the scale of mere decimetres. This may have important ecological as well as evolutionary implications.



2018 ◽  
Author(s):  
Jan Klecka ◽  
Jiří Hadrava ◽  
Pavla Koloušková

Visitation of plants by different pollinators depends on individual plant traits, spatial context, and other factors. A neglected aspect of small-scale variation of plant-pollinator interactions is the role of vertical position of flowers. We conducted a series of experiments to study vertical stratification of plant-pollinator interactions in a dry grassland. We observed flower visitors on cut inflorescences of Centaurea scabiosa and Inula salicina placed at different heights above ground in two types of surrounding vegetation: short and tall. Even at such a small-scale, we detected significant shift in total visitation rate of inflorescences in response to their vertical position. In short vegetation, inflorescences close to the ground were visited more frequently, while in tall vegetation, inflorescences placed higher received more visits. Moreover, we found major differences in the composition of the pollinator community on flowers at different heights. In a second experiment, we measured flower visitation rate in inflorescences of Salvia verticillata of variable height. Total flower visitation rate increased markedly with inflorescence height in this case. Data on seed set of individual plants provide evidence for a corresponding positive pollinator-mediated selection on increased inflorescence height. Overall, our results demonstrate strong vertical stratification of plant-pollinator interactions at the scale of mere decimetres. This may have important ecological as well as evolutionary implications.



2018 ◽  
Author(s):  
Jan Klecka ◽  
Jiří Hadrava ◽  
Pavla Koloušková

Visitation of plants by different pollinators depends on individual plant traits, spatial context, and other factors. A neglected aspect of small-scale variation of plant-pollinator interactions is the role of vertical position of flowers. We conducted a series of experiments to study vertical stratification of plant-pollinator interactions in a dry grassland. We observed flower visitors on cut inflorescences of Centaurea scabiosa and Inula salicina placed at different heights above ground in two types of surrounding vegetation: short and tall. Even at such a small-scale, we detected significant shift in total visitation rate of inflorescences in response to their vertical position. In short vegetation, inflorescences close to the ground were visited more frequently, while in tall vegetation, inflorescences placed higher received more visits. Moreover, we found major differences in the composition of the pollinator community on flowers at different heights. In a second experiment, we measured flower visitation rate in inflorescences of Salvia verticillata of variable height. Total flower visitation rate increased markedly with inflorescence height in this case. Data on seed set of individual plants provide evidence for a corresponding positive pollinator-mediated selection on increased inflorescence height. Overall, our results demonstrate strong vertical stratification of plant-pollinator interactions at the scale of mere decimetres. This may have important ecological as well as evolutionary implications.



2017 ◽  
Author(s):  
Jan Klecka ◽  
Jiří Hadrava ◽  
Pavla Koloušková

Interactions between plants and their pollinators vary in time and space at different scales. A neglected aspect of small-scale variation of plant-pollinator interactions is the role of vertical position of flowers. We conducted a series of experiments to study vertical stratification of plant-pollinator interactions in a dry grassland. We observed flower visitors on cut inflorescences of Centaurea scabiosa and Inula salicina placed at different heights above ground in two types of surrounding vegetation: short and tall. Even at such a small-scale, we detected significant shift in total visitation rate of inflorescences in response to their vertical position. In short vegetation, inflorescences close to the ground were visited more frequently, while in high vegetation, inflorescences placed higher received more visits. Moreover, we found major differences in the composition of the pollinator community on flowers at different heights. In a second experiment, we measured flower visitation rate in inflorescences of Salvia verticillata of variable height. Overall flower visitation rate increased markedly with inflorescence height. We also detected a corresponding positive pollinator-mediated selection on increased inflorescence height using data on seed set of individual plants. Overall, our results demonstrate strong vertical stratification of plant-pollinator interactions at the scale of mere decimetres. This may be an important, albeit underappreciated, driver of plant-pollinator coevolution.



2020 ◽  
Vol 51 (1) ◽  
pp. 319-340
Author(s):  
Amanda D. Benoit ◽  
Susan Kalisz

Plants are the foundation of the food web and therefore interact directly and indirectly with myriad organisms at higher trophic levels. They directly provide nourishment to mutualistic and antagonistic primary consumers (e.g., pollinators and herbivores), which in turn are consumed by predators. These interactions produce cascading indirect effects on plants (either trait-mediated or density-mediated). We review how predators affect plant-pollinator interactions and thus how predators indirectly affect plant reproduction, fitness, mating systems, and trait evolution. Predators can influence pollinator abundance and foraging behavior. In many cases, predators cause pollinators to visit plants less frequently and for shorter durations. This decline in visitation can lead to pollen limitation and decreased seed set. However, alternative outcomes can result due to differences in predator, pollinator, and plant functional traits as well as due to altered interaction networks with plant enemies. Furthermore, predators may indirectly affect the evolution of plant traits and mating systems.



2018 ◽  
Vol 285 (1880) ◽  
pp. 20180635 ◽  
Author(s):  
Matthew H. Koski ◽  
Jennifer L. Ison ◽  
Ashley Padilla ◽  
Angela Q. Pham ◽  
Laura F. Galloway

Seemingly mutualistic relationships can be exploited, in some cases reducing fitness of the exploited species. In plants, the insufficient receipt of pollen limits reproduction. While infrequent pollination commonly underlies pollen limitation (PL), frequent interactions with low-efficiency, exploitative pollinators may also cause PL. In the widespread protandrous herb Campanula americana , visitation by three pollinators explained 63% of the variation in PL among populations spanning the range. Bumblebees and the medium-sized Megachile campanulae enhanced reproductive success, but small solitary bees exacerbated PL. To dissect mechanisms behind these relationships, we scored sex-specific floral visitation, and the contributions of each pollinator to plant fitness using single flower visits. Small bees and M. campanulae overvisited male-phase flowers, but bumblebees frequently visited female-phase flowers. Fewer bumblebee visits were required to saturate seed set compared to other bees. Scaling pollinator efficiency metrics to populations, small bees deplete large amounts of pollen due to highly male-biased flower visitation and infrequent pollen deposition. Thus, small bees reduce plant reproduction by limiting pollen available for transfer by efficient pollinators, and appear to exploit the plant–pollinator mutualism, acting as functional parasites to C. americana . It is therefore unlikely that small bees will compensate for reproductive failure in C. americana when bumblebees are scarce.



2018 ◽  
Vol 12 (3) ◽  
pp. 339-349 ◽  
Author(s):  
Adinda Vanommeslaeghe ◽  
Ivan Meeus ◽  
Gerda Cnops ◽  
Tim Vleugels ◽  
Martine Merchiers ◽  
...  


Insects ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 512
Author(s):  
Liam M. Crowley ◽  
Jonathan P. Sadler ◽  
Jeremy Pritchard ◽  
Scott A. L. Hayward

The impact of elevated CO2 (eCO2) on plant–pollinator interactions is poorly understood. This study provides the first systematic review of this topic and identifies important knowledge gaps. In addition, we present field data assessing the impact of eCO2 (150 ppm above ambient) on bluebell (Hyacinthoides non-scripta)–pollinator interactions within a mature, deciduous woodland system. Since 1956, only 71 primary papers have investigated eCO2 effects on flowering time, floral traits and pollination, with a mere 3 studies measuring the impact on pollination interactions. Our field experiment documented flowering phenology, flower visitation and seed production, as well as the abundance and phenology of dominant insect pollinators. We show that first and mid-point flowering occurred 6 days earlier under eCO2, but with no change in flowering duration. Syrphid flies and bumble bees were the dominant flower visitors, with peak activity recorded during mid- and late-flowering periods. Whilst no significant difference was recorded in total visitation or seed set between eCO2 and ambient treatments, there were clear patterns of earlier flowering under eCO2 accompanied by lower pollinator activity during this period. This has implications for potential loss of synchrony in pollination systems under future climate scenarios, with associated long-term impacts on abundance and diversity.



2020 ◽  
Vol 125 (7) ◽  
pp. 1003-1012 ◽  
Author(s):  
Tia-Lynn Ashman ◽  
Conchita Alonso ◽  
Victor Parra-Tabla ◽  
Gerardo Arceo-Gómez

Abstract Background Pollen transfer via animals is necessary for reproduction by ~80 % of flowering plants, and most of these plants live in multispecies communities where they can share pollinators. While diffuse plant–pollinator interactions are increasingly recognized as the rule rather than the exception, their fitness consequences cannot be deduced from flower visitation alone, so other proxies, functionally closer to seed production and amenable for use in a broad variety of diverse communities, are necessary. Scope We conceptually summarize how the study of pollen on stigmas of spent flowers can reflect key drivers and functional aspects of the plant–pollinator interaction (e.g. competition, facilitation or commensalism). We critically evaluate how variable visitation rates and other factors (pollinator pool and floral avoidance) can give rise to different relationships between heterospecific pollen and (1) conspecific pollen on the stigma and (2) conspecific tubes/grain in the style, revealing the complexity of potential interpretations. We advise on best practices for using these proxies, noting the assumptions and caveats involved in their use, and explicate what additional data are required to verify interpretation of given patterns. Conclusions We conclude that characterizing pollen on stigmas of spent flowers provides an attainable indirect measure of pollination interactions, but given the complex processes of pollen transfer that generate patterns of conspecific–heterospecific pollen on stigmas these cannot alone determine whether competition or facilitation are the underlying drivers. Thus, functional tests are also needed to validate these hypotheses.



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