Pollinator effectiveness of a specialist bee exploiting a generalist plant—tracking pollen transfer by Heriades truncorum with quantum dots

AbstractHeriades truncorum (Megachilidae) is a specialist bee that forages on Asteraceae and collects pollen by tapping its abdomen on pollen-presenting florets which places the grains directly in the ventral scopa. We tracked pollen transfer by female H. truncorum between conspecific inflorescences of Inula ensifolia and Pulicaria dysenterica by labelling pollen with quantum dots. On average, bees transferred 31.14 (I. ensifolia) and 9.96 (P. dysenterica) pollen grains from the last visited inflorescence, 39% and 45% of which were placed on receptive styles. Pollen germination ratio is significantly lower for inflorescences of P. dysenterica visited by one H. truncorum (0.13%) compared with open control inflorescences (0.51%), which suggests that the bees mainly transfer self-pollen of these self-incompatible plants. Thus, a single visit by H. truncorum does not grant the plant high reproductive success, but the bees’ abundance and flower constancy might reduce this disadvantage.

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Generalist birds outperform specialist sunbirds as pollinators of an African Aloe

Biology Letters ◽

10.1098/rsbl.2019.0349 ◽

2019 ◽

Vol 15 (7) ◽

pp. 20190349 ◽

Cited By ~ 3

Author(s):

Carolina Diller ◽

Miguel Castañeda-Zárate ◽

Steven D. Johnson

Keyword(s):

Seed Production ◽

Pollen Grains ◽

Pollen Transfer ◽

Bird Pollination ◽

Single Visit ◽

Highly Effective ◽

Aloe Ferox ◽

Pollination Systems ◽

Effective Pollinators

Bird pollination systems are dominated by specialist nectarivores, such as hummingbirds in the Americas and sunbirds in Africa. Opportunistic (generalist) avian nectarivores such as orioles, weavers and bulbuls have also been implicated as plant pollinators, but their effectiveness as agents of pollen transfer is poorly known. Here, we compare the single-visit effectiveness of specialist and opportunistic avian nectarivores as pollinators of Aloe ferox, a plant that relies almost exclusively on birds for seed production. We found that the number of pollen grains on stigmas of flowers receiving single visits by opportunistic avian nectarivores was approximately threefold greater than on those receiving single visits by specialist sunbirds and about twofold greater than on those that received single visits by honeybees. The number of pollen grains on stigmas of flowers visited by sunbirds was similar to that on stigmas of unvisited flowers. These results show that opportunistic birds are highly effective pollinators of A. ferox , supporting the idea that some plants are specialized for pollination by opportunistic birds.

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Estimating pollinator performance of visitors to the self-incompatible crop-plant Brassica rapa by single visit deposition and pollen germination: a comparison of methods.

Journal of Pollination Ecology ◽

10.26786/1920-7603(2017)420 ◽

2017 ◽

Vol 21 ◽

Author(s):

Robert Brian Patchett ◽

Gavin Ballantyne ◽

Patricia Gillian Willmer

Keyword(s):

Brassica Rapa ◽

Pollen Germination ◽

Relative Effectiveness ◽

Pollen Grains ◽

The Self ◽

Pollen Deposition ◽

Single Visit ◽

Pollinator Performance ◽

Insect Visitors

Estimating the pollen-deposition effectiveness of flower visitors is fundamental to understanding their performance as pollinators. While estimates of visitation rates, pollen loads, and single visit deposition (SVD) are all useful proxies for performance, and so help to reveal the relative effectiveness of different visitors, none take into account the breeding system of the plants, or the quality of pollen deposited. Here we compare the performance of visitors to the self-incompatible plant Brassica rapa (turnip) using SVD and pollen germination. We also report the first use of the staining of Brassica rapa stigma papilla cells (known to reveal a specific reaction to self-pollen) to compare self-pollen deposition between insect visitors. We found that most of the pollen grains deposited by insect visitors (and therefore counted by SVD methods) were non-germinating self-pollen. A smaller proportion of grains were outcrossed and so germinated. There was also a significant positive relationship between environmental conditions (wind speed) and pollen deposition, but not pollen germination.Both methods identified Bombus spp. as the best-performing visitors on turnip flowers, followed by Eristalis spp., whereas performance estimates for Episyrphus balteatus and ‘other hoverflies’ were no higher than controls for both methods. This study provides further insight into the methodology for estimating pollinator performance, especially in plants when only cross-pollen can germinate.

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Pollinator effectiveness and importance between female and male mining bee ( Andrena )

Biology Letters ◽

10.1098/rsbl.2019.0479 ◽

2019 ◽

Vol 15 (10) ◽

pp. 20190479 ◽

Cited By ~ 2

Author(s):

Ju Tang ◽

Qiu-Mei Quan ◽

Jing-Zhu Chen ◽

Ting Wu ◽

Shuang-Quan Huang

Keyword(s):

Foraging Behaviour ◽

Pollen Grains ◽

Pollen Foraging ◽

Pollen Transfer ◽

Natural Ecosystems ◽

Pollinator Effectiveness ◽

Visit Frequency ◽

Pollen Transfer Efficiency ◽

Food Provision ◽

Effective Pollinators

Bees are often considered to be effective pollinators in both agricultural and natural ecosystems but could be ineffective pollinators in that they collect large quantities of pollen for food provision but deliver little to stigmas. Male bees do not collect pollen to feed larvae, and their pollination role has been underappreciated. Here we compare pollination effectiveness, visit frequency and pollen foraging behaviour between female and male individuals of a mining bee, Andrena emeishanica , visiting a nectariferous spring flower ( Epimedium pubescens ). Female bees were observed to forage for both pollen and nectar, but male bees foraged only for nectar. Female bees had large hairy hind tibiae with conspicuous scopae, and nearly 90% of the pollen grains they collected went onto the hind legs. Male bees removed less pollen from anthers than female bees but deposited more pollen on stigmas per visit. The higher pollen transfer efficiency of male bees was due to 48.4% of pollen grains remaining ungroomed on the thorax and abdomen, available for stigma contact, but their visitation rate to flowers was much lower. Our results indicate that male solitary bees could transfer more pollen on the stigma per visit but were less important (transferred less pollen in total, because they made fewer visits per unit time) than females.

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Asymmetric pollen transfer and reproductive success of the hawkmoth-pollinated distylous tree Palicourea tetragona (Rubiaceae) at La Selva, Costa Rica

Journal of Tropical Ecology ◽

10.1017/s0266467413000588 ◽

2013 ◽

Vol 29 (6) ◽

pp. 501-510 ◽

Cited By ~ 4

Author(s):

Silvana Martén-Rodríguez ◽

Paola Muñoz-Gamboa ◽

Ruth Delgado-Dávila ◽

Mauricio Quesada

Keyword(s):

Costa Rica ◽

Reproductive Success ◽

Fruit Set ◽

Pollen Grains ◽

Pollen Transfer ◽

Female Reproductive Success ◽

Pollinator Visitation ◽

La Selva ◽

Floral Variation ◽

Sexual Interference

Abstract:Distyly is a floral polymorphism that presumably evolved to facilitate cross-pollination and to prevent sexual interference. However, pollen transfer is often asymmetric, with one floral morph acting as a pollen donor and the other as a pollen recipient. We evaluated the association between floral morphology, pollinator visitation and effectiveness on patterns of pollen transfer in distylous Palicourea tetragona at La Selva Biological Station in Costa Rica. To assess floral variation we measured corolla, pistil and stamen traits from 66 plants. We quantified pollinator visitation and efficiency on 56 individuals and counted pollen loads on stigmas of flowers observed for 1 h. We determined fruit set 2 mo later and assessed between-morph variation in pollen transfer and female reproductive success. Floral variation was mostly consistent with a typical distylous system; however, there was overlap in the stigma heights of pin and thrum individuals in the study population. Primary pollinators were two species of hawkmoths that visited both morphs at a frequency of 2 visits per flower h−1. The mean number of pollen grains deposited on stigmas was 89 for pin and 153 for thrum individuals. However, loads of illegitimate pollen were higher on stigmas of thrum individuals, while loads of legitimate pollen were higher on stigmas of pin individuals. Consistently, fruit set was higher in pin (31%) than in thrum individuals (22%). High deposition of illegitimate pollen, in addition to the lower female reproductive success in the thrum morph reveal that distyly in P. tetragona does not always prevent sexual interference. We suggest that in long and narrow tubular flowers, like those of P. tetragona, stigma clogging by deposition of self- or same-morph pollen may reduce legitimate fertilization of ovules causing the observed asymmetric fruit set.

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Effects of herbivory and its timing on reproductive success of a tropical deciduous tree

Annals of Botany ◽

10.1093/aob/mcaa117 ◽

2020 ◽

Vol 126 (5) ◽

pp. 957-969

Author(s):

Enya N Quiroz-Pacheco ◽

Francisco Mora ◽

Karina Boege ◽

César A Domínguez ◽

Ek del-Val

Keyword(s):

Reproductive Success ◽

Structural Equation ◽

Structural Equation Models ◽

Pollen Grains ◽

Leaf Damage ◽

Deciduous Tree ◽

Herbivore Damage ◽

Male And Female ◽

Foliar Damage ◽

The Impact

Abstract Background and Aims The implications of herbivory for plant reproduction have been widely studied; however, the relationship of defoliation and reproductive success is not linear, as there are many interacting factors that may influence reproductive responses to herbivore damage. In this study we aimed to disentangle how the timing of foliar damage impacts both male and female components of fitness, and to assess when it has greater impacts on plant reproductive success. Methods We measured herbivore damage and its effects on floral production, male and female floral attributes as well as fruit yield in three different phenological phases of Casearia nitida (Salicaceae) over the course of two consecutive years. Then we tested two models of multiple causal links among herbivory and reproductive success using piecewise structural equation models. Key Results The effects of leaf damage differed between reproductive seasons and between male and female components of fitness. Moreover, the impact of herbivory extended beyond the year when it was exerted. The previous season’s cumulated foliar damage had the largest impact on reproductive characters, in particular a negative effect on the numbers of inflorescences, flowers and pollen grains, indirectly affecting the numbers of infructescences and fruits, and a positive one on the amount of foliar damage during flowering. Conclusions For perennial and proleptic species, the dynamics of resource acquisition and allocation patterns for reproduction promote and extend the effects of herbivore damage to longer periods than a single reproductive event and growing season, through the interactions among different components of female and male fitness.

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Biology of Flowering, Fruit and Viability of Pollen of Varieties and Forms of Quince Cultivated on the Territory of the Nakhchivan Autonomous Republic

Bulletin of Science and Practice ◽

10.33619/2414-2948/64/07 ◽

2021 ◽

Vol 7 (3) ◽

pp. 64-69

Author(s):

L. Bayramov

Keyword(s):

Pollen Fertility ◽

Pollen Germination ◽

Glucose Solution ◽

Pollen Viability ◽

Pollen Grains ◽

Weather Conditions ◽

Distilled Water ◽

Water Control ◽

Germinated Pollen ◽

Autonomous Republic

Abstract. The zones of distribution of varieties and forms of quince on the territory of the Nakhchivan Autonomous Republic have been established, phenological observations have been carried out, their flowering and fruiting have been studied. On the territory of the Autonomous Republic, flowering of varieties and forms of quince begins in the second decade of April, depending on the distribution zone, with an average daily temperature of 12–13 °C and lasts 12–13 days, depending on weather conditions. Each flower has 10–12 stamens arranged in one row. The article also studied the viability of pollen in a number of quince varieties. Pollen viability was studied in the varieties Sary, Tursh, Ordubad, Gara and wild forms. Pollen fertility was determined by staining with acetocarmine. Pollen germinates in 2–5–10–15 and 20% glucose solution. Counting of germinated pollen grains was carried out under a microscope. The study showed that of all the experimental varieties, the pollen fertility of the Sary quince and Tursh quince varieties is high (up to 96.6–97.1%). The best medium for the germination of quince pollen is a 10–15% glucose solution. Pollen germination in this solution reaches 47.4–88.0%. In distilled water (control), the germination of quince pollen reached from 9.7% to 35.6% for varieties. Quince pollen remains viable for 31–43 days.

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Impact of Manganese on Pollen Germination and Tube Growth in Lily

Acta Agrobotanica ◽

10.5586/aa.746 ◽

2021 ◽

Vol 74 ◽

Author(s):

Thomas Sawidis ◽

Gülriz Baycu ◽

Elżbieta Weryszko-Chmielewska ◽

Aneta Sulborska

Keyword(s):

Pollen Tube ◽

Pollen Germination ◽

Surrounding Medium ◽

Pollen Grains ◽

Lilium Longiflorum ◽

Tube Growth ◽

Low Concentrations ◽

Main Effect

Abstract In vitro culture of Lilium longiflorum pollen grains was carried out to determine the role of manganese in pollen germination and pollen tube growth. Pollen germination was adversely affected by the presence of manganese (>10 −8 M), whereas low concentrations (10 −12 –10 −10 M) stimulated the process. Manganese caused morphological anomalies during tube growth, characterized by irregular pollen tube thickening and swollen tips. The main effect was the anomalous cell wall formation at the tip, in which the presence of several organelles reduced the number of secretory vesicles. A loose network of fibrillar material and spherical aggregates, mostly in the tip region, was detected, and this material was progressively loosened into the surrounding medium. As a response to potential toxicity, the excess manganese was isolated in vacuoles, which formed an internal barrier against penetration of manganese to the tip area. Elevated manganese concentrations might affect plant reproduction, resulting in anomalies in gamete development. Consequently, the loss in genetic diversity and decreased fruit set ultimately lower yield.

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Types of Flower Visitors: Syndromes, Constancy, and Effectiveness

Pollination and Floral Ecology ◽

10.23943/princeton/9780691128610.003.0011 ◽

2011 ◽

Author(s):

Pat Willmer

Keyword(s):

Adaptive Radiation ◽

Convergent Evolution ◽

Pollination Syndromes ◽

Pollinator Effectiveness ◽

Flower Constancy ◽

Flower Visitors ◽

Floral Constancy ◽

Effective Pollinators

This chapter examines pollination syndromes, floral constancy, and pollinator effectiveness. Flowers show enormous adaptive radiation, but the same kind of flower reappears by convergent evolution in many different families. Thus many families produce rather similar, simple bowl-shaped flowers like buttercups; many produce similar zygomorphic tubular lipped flowers; and many produce fluffy flower heads of massed (often white) florets. These broad flower types are the basis of the idea of pollination syndromes—the flowers have converged on certain morphologies and reward patterns because they are exploiting the abilities and preferences of particular kinds of visitor. After providing an overview of pollination syndromes, the chapter explains why pollination syndromes can be defended. It then considers flower constancy, along with the distinction between flower visitors and effective pollinators. It concludes with some observations on how flower visitors can contribute to speciation of plants through specialization and through their constancy.

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Breeding biology and distyly in Palicourea rigida H. B. & K. (Rubiaceae) in the Cerrados of Central Brazil

Acta Botanica Brasilica ◽

10.1590/s0102-33062010000300012 ◽

2010 ◽

Vol 24 (3) ◽

pp. 686-696 ◽

Cited By ~ 15

Author(s):

Adriana de Oliveira Machado ◽

Ana Palmira Silva ◽

Helder Consolaro ◽

Mariluza A. Granja e Barros ◽

Paulo Eugênio Oliveira

Keyword(s):

Reproductive Success ◽

Fruit Set ◽

Pollen Grains ◽

Floral Biology ◽

Nectar Production ◽

Central Brazil ◽

Palicourea Rigida ◽

Floral Visitors ◽

Compatible Pollen ◽

Incompatibility Reactions

Distyly is a floral polymorphism more common among the Rubiaceae than in any other angiosperm group. Palicourea rigida is a typically distylous species of the Rubiaceae widely distributed in the Brazilian Cerrados. This work aimed to study the floral biology and breeding system of P. rigida in order to verify if there wasasymmetry between floral morphs. The work was carried out at Fazenda Água Limpa, Brasília-DF, from 1993 to 1995; and at Serra Caldas Novas State Park-Goias and in Clube Caça e Pesca Itororó de Uberlândia-Minas Gerais in 2005 and 2006. Density, height and pin/thrum ratio were assessed for flowering individuals in all areas. Plants were investigated for differences in floral morphology, nectar production, reproductive success and site of self incompatibility reactions. Blooming period was long and concentrated during the rains. Flowers were clearly distylous and with reciprocal herkogamy. They produced nectar and lasted for a single day. In spite of differences in density and height, populations were mostly isoplethic. Nectar production varied in volume and concentration but the differences could not be associated with floral morphs. The species is self-incompatible but reproductive success was always high and independent of floral morphs. There were differences in the site of incompatibility barriers between floral morphs, which were similar to those observed for other Rubiaceae. The main floral visitors and pollinators were the hummingbirds Colibri serrirostris and Eupetomena macroura. High fruit-set indicates that the pollinators transported enough compatible pollen grains between floral morphs, despite their territorial behavior.

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Effect of high temperature on the reproductive development of chickpea genotypes under controlled environments

Functional Plant Biology ◽

10.1071/fp12033 ◽

2012 ◽

Vol 39 (12) ◽

pp. 1009 ◽

Cited By ~ 72

Author(s):

Viola Devasirvatham ◽

Pooran M. Gaur ◽

Nalini Mallikarjuna ◽

Raju N. Tokachichu ◽

Richard M. Trethowan ◽

...

Keyword(s):

Heat Stress ◽

High Temperature ◽

Pollen Germination ◽

Pollen Viability ◽

Pollen Grains ◽

High Temperature Stress ◽

Pollen Production ◽

Seed Number ◽

Controlled Environments

High temperature during the reproductive stage in chickpea (Cicer arietinum L.) is a major cause of yield loss. The objective of this research was to determine whether that variation can be explained by differences in anther and pollen development under heat stress: the effect of high temperature during the pre- and post-anthesis periods on pollen viability, pollen germination in a medium, pollen germination on the stigma, pollen tube growth and pod set in a heat-tolerant (ICCV 92944) and a heat-sensitive (ICC 5912) genotype was studied. The plants were evaluated under heat stress and non-heat stress conditions in controlled environments. High temperature stress (29/16°C to 40/25°C) was gradually applied at flowering to study pollen viability and stigma receptivity including flower production, pod set and seed number. This was compared with a non-stress treatment (27/16°C). The high temperatures reduced pod set by reducing pollen viability and pollen production per flower. The ICCV 92944 pollen was viable at 35/20°C (41% fertile) and at 40/25°C (13% fertile), whereas ICC 5912 pollen was completely sterile at 35/20°C with no in vitro germination and no germination on the stigma. However, the stigma of ICC 5912 remained receptive at 35/20°C and non-stressed pollen (27/16°C) germinated on it during reciprocal crossing. These data indicate that pollen grains were more sensitive to high temperature than the stigma in chickpea. High temperature also reduced pollen production per flower, % pollen germination, pod set and seed number.

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