scholarly journals Temporal changes in the most effective pollinator of a bromeliad pollinated by bees and hummingbirds

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e8836 ◽  
Author(s):  
Roberta Luisa Barbosa Leal ◽  
Marina Muniz Moreira ◽  
Alessandra Ribeiro Pinto ◽  
Júlia de Oliveira Ferreira ◽  
Miguel Rodriguez-Girones ◽  
...  

A generalist pollination system may be characterized through the interaction of a plant species with two or more functional groups of pollinators. The spatiotemporal variation of the most effective pollinator is the factor most frequently advocated to explain the emergence and maintenance of generalist pollination systems. There are few studies merging variation in floral visitor assemblages and the efficacy of pollination by different functional groups. Thus, there are gaps in our knowledge about the variation in time of pollinator efficacy and frequency of generalist species. In this study, we evaluated the pollination efficacy of the floral visitors of Edmundoa lindenii (Bromeliaceae) and their frequency of visits across four reproductive events. We analyzed the frequency of the three groups of floral visitors (large bees, small bees, and hummingbirds) through focal observations in the reproductive events of 2015, 2016, 2017, and 2018. We evaluated the pollination efficacy (fecundity after one visit) through selective exposure treatments and the breeding system by manual pollinations. We tested if the reproductive success after natural pollination varied between the reproductive events and also calculated the pollen limitation index. E. lindenii is a self-incompatible and parthenocarpic species, requiring the action of pollinators for sexual reproduction. Hummingbirds had higher efficacy than large bees and small bees acted only as pollen larcenists. The relative frequency of the groups of floral visitors varied between the reproductive events. Pollen limitation has occurred only in the reproductive event of 2017, when visits by hummingbirds were scarce and reproductive success after natural pollination was the lowest. We conclude that hummingbirds and large bees were the main and the secondary pollinators of E. lindenii, respectively, and that temporal variations in the pollinator assemblages had effects on its reproductive success. Despite their lower pollination efficacy, large bees ensured seed set when hummingbirds failed. Thus, we provide evidence that variable pollination environments may favor generalization, even under differential effectiveness of pollinator groups if secondary pollinators provide reproductive assurance.

Hoehnea ◽  
2019 ◽  
Vol 46 (1) ◽  
Author(s):  
Adriana de Oliveira Fidalgo ◽  
Aline Testoni Cécel ◽  
Juliana Ferrari de Oliveira Mazzi ◽  
Claudio José Barbedo

ABSTRACT This work evaluated the effect of pollination on the quality of seeds and plantlets of Eugenia uniflora L., as well as on the regenerative capacity of the seeds. Twelve individuals were monitored for their phenology and their floral visitors. Recently-opened flowers were subjected to self-pollination (SP), cross-pollination (CP) and natural pollination/control (C) treatments. The seeds obtained were evaluated for their germination and the resulting seedlings were transferred to a greenhouse and evaluated for their height, stem diameter, number of leaves, leaf area and fresh and dry mass of root, stem, and leaves. SP, CP and C seeds were fractionated into two and four parts and evaluated for their ability to germinate and produce normal seedlings. Seeds and seedlings from manual cross-pollination were the most vigorous. The worst performance of the natural pollination (C) evidenced the pollen limitation caused by the scarcity of efficient pollinators in the study area.


2020 ◽  
Author(s):  
Tetsuya K Matsumoto ◽  
Muneto Hirobe ◽  
Masahiro Sueyoshi ◽  
Yuko Miyazaki

Abstract Background and Aims Interspecific difference in pollinators (pollinator isolation) is important for reproductive isolation in flowering plants. Species-specific pollination by fungus gnats has been discovered in several plant taxa, suggesting that they can contribute to reproductive isolation. Nevertheless, their contribution has not been studied in detail, partly because they are too small for field observations during flower visitation. To quantify their flower visitation, we used the genus Arisaema (Araceae) because the pitcher-like spathe of Arisaema can trap all floral visitors. Methods We evaluated floral visitor assemblage in an altitudinal gradient including five Arisaema species. We also examined interspecific differences in altitudinal distribution (geographic isolation) and flowering phenology (phenological isolation). To exclude the effect of interspecific differences in altitudinal distribution on floral visitor assemblage, we established 10 experimental plots including the five Arisaema species on high- and low-altitude areas and collected floral visitors. We also collected floral visitors in three additional sites. Finally, we estimated the strength and contribution of these three reproductive barriers using the unified formula for reproductive isolation. Key Results Each Arisaema species selectively attracted different fungus gnats in the altitudinal gradient, experimental plots, and additional sites. Altitudinal distribution and flowering phenology differed among the five Arisaema species, whereas the strength of geographic and phenological isolations were distinctly weaker than those in pollinator isolation. Nevertheless, the absolute contribution of pollinator isolation to total reproductive isolation was weaker than geographic and phenological isolations, because pollinator isolation functions after the two early-acting barriers in plant life history. Conclusions Our results suggest that selective pollination by fungus gnats potentially contributes to reproductive isolation. Since geographic and phenological isolations can be disrupted by habitat disturbance and interannual climate change, the strong and stable pollinator isolation might compensate for the weakened early-acting barriers as an alternative reproductive isolation among the five Arisaema species.


2018 ◽  
Vol 24 (1) ◽  
pp. 42-51
Author(s):  
Yuji Tokumoto ◽  
Michinari Matsushita ◽  
Keiko Kishimoto-Yamada ◽  
Aoi Nikkeshi ◽  
Tomohiro Isogimi ◽  
...  

2012 ◽  
Vol 5 (1) ◽  
pp. 29-32
Author(s):  
Fábio Castro Verçoza

Este trabalho apresenta dados sobre a fenologia reprodutiva, a biologia floral e a ecologia da polinização de Vellozia candida Mikan (Velloziaceae) nos afloramentos rochosos do Costão de Itacoatiara, Niterói, RJ. Uma população de dez indivíduos da espécie foi estudada nessa localidade no período de junho de 2006 a dezembro de 2008. Foram realizadas observações sobre período de floração, morfologia, cor e odor das flores, ocorrência e comportamento dos visitantes florais. A floração de V. candida ocorreu de setembro a dezembro nos dois anos consecutivos do estudo. As flores são brancas, nectaríferas e exalam odor suave e adocicado. Reúnem características típicas da síndrome da melitofilia e foram intensamente visitadas por três espécies de abelhas. Xylocopa ordinaria Smith se destacou como o polinizador efetivo da espécie estudada. Por ser uma abelha de grande porte e robusta, durante a coleta de néctar e de pólen, deposita este último no estigma, polinizando as flores. Pollination of Vellozia candida Mikan (Velloziaceae) on Rock Outcrops of Costão de Itacoatiara, Niterói, RJ: A Case of Mellitophily Inselberg BrazilAbstract. This paper presents data on the reproductive phenology, floral biology and pollination ecology of Vellozia candida Mikan (Velloziaceae) on rocky outcrops of Costão Itacoatiara, Niterói, RJ. A population of ten individuals of the species was studied in this location from June 2006 to December 2008. Observations were made on flowering period, morphology, color and odor of flowers, the occurrence and behavior of floral visitors. The flowering of V. candida occurred from September to December in two successive years of study. The flowers are white, exude nectar and sweet odor. Meet typical syndrome melitophyly and were intensively visited by three species of bees. Xylocopa ordinaria Smith stood out as the effective pollinator of the species studied. Being a bee large and robust, while collecting nectar and pollen, the latter deposited on the stigma, pollinating the flowers.


Author(s):  
Anke Kloock ◽  
Lena Peters ◽  
Charlotte Rafaluk-Mohr

In most animals, female investment in offspring production is greater than for males. Lifetime reproductive success (LRS) is predicted to be optimized in females through extended lifespans to maximize reproductive events by increased investment in immunity. Males, however, maximize lifetime reproductive success by obtaining as many matings as possible. In populations consisting of mainly hermaphrodites, optimization of reproductive success may be primarily influenced by gamete and resource availability. Microbe-mediated protection (MMP) is known to affect both immunity and reproduction, but whether sex influences the response to MMP remains to be explored. Here, we investigated the sex-specific differences in survival, behavior, and timing of offspring production between feminized hermaphrodite (female) and male Caenorhabditis elegans following pathogenic infection with Staphylococcus aureus with or without MMP by Enterococcus faecalis. Overall, female survival decreased with increased mating. With MMP, females increased investment into offspring production, while males displayed higher behavioral activity. MMP was furthermore able to dampen costs that females experience due to mating with males. These results demonstrate that strategies employed under pathogen infection with and without MMP are sex dependent.


2010 ◽  
Vol 24 (3) ◽  
pp. 686-696 ◽  
Author(s):  
Adriana de Oliveira Machado ◽  
Ana Palmira Silva ◽  
Helder Consolaro ◽  
Mariluza A. Granja e Barros ◽  
Paulo Eugênio Oliveira

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.


2019 ◽  
Vol 35 (4) ◽  
pp. 185-198 ◽  
Author(s):  
Allison Louthan ◽  
Emily Valencia ◽  
Dino J. Martins ◽  
Travis Guy ◽  
Jacob Goheen ◽  
...  

AbstractCascading effects of high trophic levels onto lower trophic levels have been documented in many ecosystems. Some studies also show evidence of extended trophic cascades, in which guilds dependent on lower trophic levels, but uninvolved in the trophic cascade themselves, are affected by the trophic cascade due to their dependence on lower trophic levels. Top-down effects of large mammals on plants could lead to a variety of extended trophic cascades on the many guilds dependent on plants, such as pollinators. In this study, floral-visitor and floral abundances and assemblages were quantified within a series of 1-ha manipulations of large-mammalian herbivore density in an African savanna. Top-down effects of large mammals on the composition of flowers available for floral visitors are first shown, using regressions of herbivore activity on metrics of floral and floral-visitor assemblages. An extended trophic cascade is also shown: the floral assemblage further altered the assemblage of floral visitors, according to a variety of approaches, including a structural equation modelling approach (model with an extended trophic cascade was supported over a model without, AICc weight = 0.984). Our study provides support for extended trophic cascades affecting floral visitors, suggesting that trophic cascades can have impacts throughout entire communities.


2019 ◽  
Vol 30 (6) ◽  
pp. 2321-2330
Author(s):  
Yanhua Zhang ◽  
Fangping Tang ◽  
Jian Ni ◽  
Lijia Dong ◽  
Lifu Sun

Abstract Species of the Ericaceae or heath family are widely distribute in continental ecosystems and their special ericoid mycorrhizas (ERM) are considered beneficial to their survival and persistence in variable habitats. Currently, increasing anthropogenic disturbances and improper forest management are affecting subtropical forests of China where these native species located. These activities not only affect plant communities above-ground, but also impose pressures on microbial communities below- ground. In this study, root-associated fungal communities of Rhododendron simsii in four forest types under different anthropogenic disturbances were identified using an Illumina Miseq platform, i.e., old growth forests, secondary forests with one cutting (SEC I), secondary forests with two cuttings (SEC II), and Chinese-fir plantations (PLF). Intra- and inter-annual variations were analyzed by comparing samples taken in different seasons and years. The results show that: (1) over 1000 OTUs were found in hair roots with most from the division Ascomycota and Basidiomycota belonging to different functional groups; (2) while there were a few indicator OTUs specific to different forest types, seasons and years, the proportion of shared taxa was quite large, accounting for 44.9–79.4% of the total OTUs; (3) significantly positive correlations were found between disturbance sensitivity and temporal variations in common fungal orders, and both in major fungal orders were significantly different among fungal functional groups in which putative and possible ERM fungi were highly resistant to disturbances and low temporal variations. The high disturbance resistance and temporal persistence of putative ERM fungi may be essential for the successful adaptation of R. simsii in disturbed subtropical forests of China.


Hoehnea ◽  
2018 ◽  
Vol 45 (1) ◽  
pp. 93-102 ◽  
Author(s):  
Adriana de Oliveira Fidalgo ◽  
Débora Marcouizos Guimarães ◽  
Gabriela Toledo Caldiron ◽  
José Marcos Barbosa

ABSTRACT The present study evaluates and compares the phenology, pollination biology and breeding systems of Chamaecrista desvauxii (Collad.) Killip.and Clitoria laurifolia Poir. in a coastal plain degraded by sand mining in São Paulo State, Brazil, from January 2006 to May 2008. Flowering and fruiting events occurred in the warm and rainy season. Both species are self-compatible but only C. desvauxii was pollinator-dependent to set fruits. A small group of bees, comprising Eufrisea sp., Eulaema (Apeulaema) cingulata and Bombus morio, accessed the male and female floral structures and moved among individuals resulting in cross-pollinations. However, only B. morio was a frequent visitor and an effective pollinator. Although recruitment and survival of population in the study area are high for both species, we observed lower abundance and richness of visitors suggesting the possible lack of pollinators and pollen limitation.


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