The cost of fidelity: foraging oligolectic bees gather huge amounts of pollen in a highly specialized cactus–pollinator association

2019 ◽  
Vol 128 (1) ◽  
pp. 30-43 ◽  
Author(s):  
Isabelle Cerceau ◽  
Samuel Siriani-Oliveira ◽  
Ana Laura Dutra ◽  
Reisla Oliveira ◽  
Clemens Schlindwein
Keyword(s):  
Male Reproductive Success ◽  
Flower Opening ◽  
Mechanical Filter ◽  
Pollen Presentation ◽  
Oligolectic Bees ◽  
The Cost ◽  
Fruit And Seed Set ◽  
Flower Handling ◽  
Plant Pollinator ◽  
Pollinator Foraging Behaviour

Abstract Plant–pollinator interactions vary along a specialization–generalization continuum. Advances in understanding the evolutionary and ecological consequences of different degrees of specialization depend on precise data on plant–pollinator interdependency. We studied the association of Parodia neohorstii (Cactaceae) and its bee pollinators focusing on pollinator foraging behaviour, flower functioning, female and male reproductive success, and pollen fate. Parodia neohorstii showed synchronized flower opening and pollen presentation but discontinuous blooming. The apparently generalized flowers partition pollen through thigmonastic stamen movements that function as a mechanical filter against generalist bees by restricting access to the major pollen reservoir to bees that show flower handling ‘know-how’, thereby favouring the oligolectic bee Arhysosage cactorum. This pollinator adjusted its pollen foraging to flower opening, removed pollen hurriedly, and promoted maximal fruit and seed set, which was minimal in its absence. Estimates of pollen fate revealed that a huge amount of pollen flows to specialized pollinators (86.5%), and only 0.9% reaches conspecific stigmas. The specialized interaction between P. neohorstii and Arhysosage cactorum, both threatened species, is efficient but fragile. Any environmental modification that causes a mismatch between the partners is likely to result in reproductive failure.

Solitary bee pollinators adjust pollen foraging to the unpredictable flower opening of a species of Petunia (Solanaceae)

2019 ◽  
Vol 129 (2) ◽  
pp. 273-287
Author(s):  
Fernanda Figueiredo De Araujo ◽  
Reisla Oliveira ◽  
Theo Mota ◽  
João Renato Stehmann ◽  
Clemens Schlindwein
Keyword(s):  
Floral Biology ◽  
Floral Resources ◽  
Pollen Foraging ◽  
Flower Opening ◽  
Foraging Patterns ◽  
Social Species ◽  
Pollen Presentation ◽  
Total Pollen ◽  
Flower Visiting ◽  
Effective Pollinators

Abstract Details of the foraging patterns of solitary bees are much less well known than those of social species, and these patterns are often adjusted to exploit floral resources of one or only a few species. The specialized flower-visiting bees of Petunia are good models for investigating such foraging patterns. Here we analysed the floral biology and pollen presentation schedule of the endangered Petunia mantiqueirensis in mixed Araucaria forests of Serra da Mantiqueira, Brazil. Pollinators and their pollen foraging behaviour and food specialization were determined through analyses of scopa pollen loads. Flowers opened throughout the day and presented all their pollen resources within the first 30 min of anthesis, thus providing their pollen resources in an asynchronous fashion in one-flower packages throughout the day. Females of Pseudagapostemon fluminensis were the most frequent flower visitors, contacting stigmas in 96% of their visits, and were the unique effective pollinators of Petunia mantiqueirensis. These pollinators were responsible for the first three visits to 115 individually monitored flowers at any daylight hour, removing ~86% of a flower’s total pollen supply during the first visit. Although female bees harvest the majority of pollen resources of Petunia mantiqueirensis, analyses of scopa loads revealed that most of them also collect pollen from plants of other families while foraging for pollen in Petunia flowers.

Costs and benefits of the mixed-mating system of Narcissus serotinus (Amaryllidaceae) in the conservation of small fragmented populations

Botany ◽  
2014 ◽  
Vol 92 (2) ◽  
pp. 113-122 ◽  
Author(s):  
Isabel Marques ◽  
David Draper ◽  
José María Iriondo
Keyword(s):  
Inbreeding Depression ◽  
Floral Biology ◽  
Mixed Mating ◽  
Reproductive Assurance ◽  
Evolutionary Potential ◽  
Mixed Mating System ◽  
Fragmented Populations ◽  
Large Populations ◽  
Fruit And Seed Set ◽  
Plant Pollinator

Small fragmented populations often exhibit reduced plant–pollinator interactions and scarce outcrossing opportunities. In this context, mixed-mating systems can be advantageous since selfing can provide reproductive assurance, but they may also carry relevant costs such as those involved in inbreeding depression. This study examines the advantages and costs of selfing in Narcissus serotinus L., a mixed-mating geophyte that currently occurs in several fragmented populations in Portugal, that resulted from the construction of the largest European dam. Observation of pollinators revealed that cross-pollination is less frequent in small than in large populations. Manual self-pollinations significantly increased fruit and seed set in small-size populations, also suggesting limited insect pollination. The existence of selfing may provide reproductive assurance in small-size populations of N. serotinus where outcrossing pollination is reduced. Although floral biology and experimental pollinations showed that N. serotinus is capable of autonomous selfing, four of the six fitness traits studied showed significant inbreeding depression in all populations. The high levels of inbreeding depression found in N. serotinus suggest that the initial reproductive assurance advantage of selfing may be counterbalanced by lower survival of the resulting individuals and a decrease in the evolutionary potential of the populations.

A half-day flowering pattern helps plants sharing pollinators in an oceanic island community

2021 ◽  
pp. 1-10
Author(s):  
Xiangping Wang ◽  
Tong Zeng ◽  
Mingsong Wu ◽  
Dianxiang Zhang
Keyword(s):  
Plant Species ◽  
Flowering Plants ◽  
Oceanic Island ◽  
Species Level ◽  
Community Level ◽  
Flower Opening ◽  
Flower Visitation ◽  
Visitation Rates ◽  
Island Community ◽  
Plant Pollinator

Abstract The temporal pattern of flower opening and closure is a feature of the biology of many plant species, particularly those inhabiting oceanic islands where flowering generally lasts for only a few hours per day. Additionally, flower visitors often seek different floral sources on a timely basis, thus the relative timing of interactions is central to their status in pollination competition, or in the facilitation of pollination among co-flowering plants sharing pollinators. However, few studies have examined the impacts of daily temporal variation in flowering patterns on the pollinator network and competition on a community scale. In order to examine whether the daily pattern of flower opening and closure can impose temporal dynamics on interspecific interactions within a single day, plant–pollinator interaction networks (AM subweb and PM subweb) were quantified, and the relevant interactions between the two subwebs were compared using the Bray–Curtis dissimilarity of visitation frequencies in an oceanic island community (Paracel Islands, South China Sea). The role of species within networks and its variation between two subwebs were assessed by calculating the species-level specialization and species strength of each plant and pollinator species. The quantitative plant–pollinator interaction dissimilarity between morning and afternoon subsets was 0.69, and this value dropped to 0.58 when considering plant species flowering throughout the day. In our study, this dissimilarity between the two subwebs might be explained by the morning peak activity rather than a preference for morning flowers. No significant differences were detected in the species-level specialization and species strength of plants flowering all day from morning to afternoon at the community level. The flower visitation rates of native honeybee Apis cerana were not significantly different between morning and afternoon for most of the whole-day flowering plants. However, plant species only flowering either in the morning or the afternoon differed in the rate of visitation by A. cerana. The analyses of variation in the visitation rates of pollinators shared by plants within a single day in the studied community suggest that daily structuring at a community level and half-day staggered flowering during the morning or afternoon might reduce competitive interactions in oceanic insular habitats.

The cost of trying: weak interspecific correlations among life-history components in male ungulates

2012 ◽  
Vol 90 (9) ◽  
pp. 1072-1085 ◽  
Author(s):  
Marco Festa-Bianchet
Keyword(s):  
Life History ◽  
Reproductive Success ◽  
Life History Traits ◽  
Male Reproductive Success ◽  
Main Determinant ◽  
Young Males ◽  
Asymptotic Size ◽  
Trade Offs ◽  
The Cost ◽  
Slow Growing

Life-history trade-offs are well known in female mammals, but have seldom been quantified for males in polygynous species. I compared age-specific mass, weapon size, survival, and reproductive success of males in eight species of ungulates, and found weak interspecific correlations among life-history traits. Young males tended to have higher reproductive success in rapidly-growing than in slow-growing species, and in species where horns or antlers reached near-asymptotic size over the first few years of life. There was no clear interspecific trade-off between early reproduction and early survival. Reproductive senescence was evident in most species. Generation length, calculated as the mean age of fathers, was negatively correlated with the reproductive success of young males and positively with life expectancy of 3-year-olds, but not with early mortality. The main determinant of male reproductive success in polygynous ungulates is the ability to prevail against competing males. Consequently, the number and age structure of competitors should strongly affect an individual’s ability to reproduce, making classic trade-offs among life-history traits very context-dependent. Most fitness costs of reproduction in male ungulates likely arise from energy expenditure and injuries sustained while attempting to mate. Individual costs may be weakly correlated with fitness returns.

scholarly journals Pollinator niche partitioning and asymmetric facilitation contribute to the maintenance of diversity

2020 ◽  
Author(s):  
Na Wei ◽  
Rainee L. Kaczorowski ◽  
Gerardo Arceo-Gómez ◽  
Elizabeth M. O’Neill ◽  
Rebecca A. Hayes ◽  
...  
Keyword(s):  
Rare Species ◽  
Niche Partitioning ◽  
Abundant Species ◽  
Transport Dynamics ◽  
Fitness Advantage ◽  
Pollinator Specialization ◽  
Biodiversity Maintenance ◽  
The Cost ◽  
Plant Pollinator ◽  
Maintenance Of Diversity

Abstract:Mechanisms that favor rare species are key to the maintenance of diversity. One of the most critical tasks for biodiversity conservation is understanding how plant–pollinator mutualisms contribute to the persistence of rare species, yet this remains poorly understood. Using a process-based model that integrates plant–pollinator and interspecific pollen transfer networks with floral functional traits, we show that niche partitioning in pollinator use and asymmetric facilitation confer fitness advantage of rare species in a biodiversity hotspot. While co-flowering species filtered pollinators via floral traits, rare species showed greater pollinator specialization leading to higher pollination-mediated male and female fitness than abundant species. When plants shared pollinator resources, asymmetric facilitation via pollen transport dynamics benefited the rare species at the cost of the abundant ones, serving as an alternative diversity-promoting mechanism. Our results emphasize the importance of community-wide plant–pollinator interactions that affect reproduction for biodiversity maintenance.

Inbreeding and competition, but not abiotic stresses, increase fluctuating asymmetry of Mimulus guttatus flowers

2020 ◽  
Vol 130 (2) ◽  
pp. 410-418
Author(s):  
Tobias M Sandner
Keyword(s):  
Fluctuating Asymmetry ◽  
Leaf Shape ◽  
Handling Time ◽  
Developmental Instability ◽  
Mimulus Guttatus ◽  
Plant Demography ◽  
Genetic Constraints ◽  
Pollinator Preference ◽  
Flower Handling ◽  
Plant Pollinator

Abstract Genetic and environmental disturbances are expected to increase developmental instability, which may result in higher fluctuating asymmetry (FA), i.e. small random deviations from symmetry. Plant leaves often do not show this pattern, possibly due to high phenotypic plasticity of leaf shape and low adaptive significance of leaf symmetry. In contrast, symmetry in many animal traits but also in flower shape is considered to be under selection, and FA in such traits may better reflect developmental instability. Using geometric morphometrics, I analysed the symmetry of flowers of inbred and outbred Mimulus guttatus (Phrymaceae) plants grown under five stress treatments with and without grass competition. Flower FA was not increased by abiotic stress, but by inbreeding and competition. As inbreeding and competition affected different principal components of flower FA, different mechanisms may be involved in their effects on FA. FA decreased with individual biomass particularly in selfed offspring, which suggests that inbreeding increased FA particularly when growth was limited by environmental or genetic constraints. Increased flower FA of inbred offspring may explain increased flower handling time and reduced pollinator preference for inbred plants in other M. guttatus studies, and could thus have important consequences for plant demography and plant–pollinator interactions.

scholarly journals A putative novel role for Eip74EF in male reproduction in promoting sperm elongation at the cost of male fecundity

2019 ◽  
Author(s):  
Sharif Chebbo ◽  
Sarah Josway ◽  
John M. Belote ◽  
Mollie K. Manier
Keyword(s):  
Reproductive Success ◽  
Oocyte Maturation ◽  
Male Reproduction ◽  
Male Reproductive Success ◽  
Sperm Length ◽  
Female Reproductive Success ◽  
Fitness Advantage ◽  
Males And Females ◽  
Opposing Effects ◽  
The Cost

ABSTRACTSpermatozoa are the most morphologically variable cell type, yet little is known about genes controlling natural variation in sperm shape. Drosophila fruit flies have the longest sperm known, which are evolving under postcopulatory sexual selection, driven by sperm competition and cryptic female choice. Long sperm outcompete short sperm but primarily when females have a long seminal receptacle (SR), the primary sperm storage organ. Thus, selection on sperm length is mediated by SR length, and the two traits are coevolving across the Drosophila lineage, driven by a genetic correlation and fitness advantage of long sperm and long SR genotypes in both males and females. Ecdysone induced protein 74EF (Eip74EF) is expressed during post-meiotic stages of spermatogenesis, when spermatid elongation occurs, and we found that it is rapidly evolving under positive selection in Drosophila. Hypomorphic knockout of the E74A isoform leads to shorter sperm but does not affect SR length, suggesting that E74A may be involved in promoting spermatid elongation but is not a genetic driver of male-female coevolution. We also found that E74A knockout has opposing effects on fecundity in males and females, with an increase in fecundity for males but a decrease in females, consistent with its documented role in oocyte maturation. Our results suggest a novel function of Eip74EF in spermatogenesis and demonstrates that this gene influences both male and female reproductive success. We speculate on possible roles for E74A in spermatogenesis and male reproductive success.RESEARCH HIGHLIGHTSEip74EF promotes oocyte maturation in Drosophila. We found evidence that it also promotes sperm elongation in males, but at a cost to male fecundity. Mutant males have shorter sperm but have higher reproductive success, while females have reduced fecundity.

scholarly journals Early Spring Nectar and Pollen and Insect Visitor Behavior in Two Corydalis Species (Papaveraceae)

2014 ◽  
Vol 58 (1) ◽  
pp. 93-102 ◽  
Author(s):  
Bożena Denisow ◽  
Monika Strzałkowska-Abramek ◽  
Małgorzata Bożek ◽  
Anna Jeżak
Keyword(s):  
Deciduous Forest ◽  
Botanical Garden ◽  
Early Morning ◽  
Early Spring ◽  
Flowering Pattern ◽  
Flower Opening ◽  
Visitor Behavior ◽  
Pollen Presentation ◽  
Current Area ◽  
The Moment

Abstract This study, conducted in 2008 and 2012 - 2013, evaluated the flowering pattern (seasonal and diurnal), the abundance of flowering, nectar, and pollen yield, and insect visitor activity for Corydalis solida (L.) Clairv. and C. cava Schweig. et Koerte. The populations occur in the ground layer of a deciduous forest (Fagetalia ordo, Querco-Fagetea class) in a natural gorge within the current area of the UMCS Botanical Garden in Lublin, Poland (51° 16’ N, 22° 30’ E). The phenology of Corydalis species showed distinct year-to-year plasticity (e.g., blooming period in March - April or in April - May; duration 18 - 42 days). The most intensive flower opening was noted in the early morning hours (85 - 90% of daily openings occurred between 6.00 and 10.00 h, GMT +2 h). The average sugar yield was similar at 4.6 kg/ha (C. cava) and 5.2 kg/ha (C. solida), but the average pollen production differed and reached 2.1 kg/ha (C. cava) and 4.1 kg/ha (C. solida). The flower-visitor interaction in Corydalis species involved both biological (early pattern of diurnal flowering, protandry, pollen presentation at the moment of anthesis) and morphological (nectar hidden in deep spur) features. Apis mellifera foragers predominated on both Corydalis species (mean of total visitors, 68.0% to C. solida; 62.5% to C. cava) and foraged mainly for pollen (82% of foragers), while bumblebee queens (mean of total visitors, 32.0% to C. solida; 37.5% to C. cava) collected mainly nectar (68.0% of foragers).

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