scholarly journals Floral biology and a pollinator effectiveness test of the diurnal floral visitors of Tabernaemontana undulata Vahl. (Apocynaceae) in the understory of Amazon Rainforest, Brazil

2011 ◽  
Vol 25 (2) ◽  
pp. 380-386 ◽  
Author(s):  
Thaysa Nogueira de Moura ◽  
Antonio Carlos Webber ◽  
Liliane Noemia Melo Torres

In this paper we examined the floral biology, per-visit effectiveness, frequency of visits and relative abundance of the diurnal floral visitor taxa of T. undulata (Apocynaceae) at two populations located in the primary forest and in a disturbed area connected to the continuous forest. Its hermaphrodite flowers show a long and narrow floral tube and introrse anthers form a cone around the apex of the style head where the pollen is deposited. The stigmatic head has three functional regions, in a complex pollination mechanism favoring cross-pollination. In the pollinator censuses conducted in the primary forest population we registered Eulaema bombiformis. In the disturbed area Euglossa sp. was responsible for visits on T. undulata fl owers. Eulaema bombiformis was not absent in the disturbed area, but preferred to forage on pollen and nectar-rich flowers of two neighboring flowering species. In the primary forest, T. undulata was the only fl owering treelet at the end of the dry season. Signifi cant differences were not observed regarding the frequency of visits and relative abundance among the diurnal flower visitors at both sites. In the per-visit effectiveness experiment among flower visitors, we observed one fruit produced aft er E. bombiformis' visits. Due to the complex breeding system of T. undulata in that it is characterized by very low fruit production even under natural conditions, an indirect measure of pollinator effectiveness is needed in at a future stage of this study in order to clarify the role of these bee species as pollinators of T. undulata.

2020 ◽  
Vol 105 (3) ◽  
pp. 281-299
Author(s):  
Javier Carreño-Barrera ◽  
Luis Alberto Núñez-Avellaneda ◽  
Maria José Sanín ◽  
Artur Campos D. Maia

Solitary, dioecious, and mostly endemic to Andean cloud forests, wax palms (Ceroxylon Bonpl. ex DC. spp.) are currently under worrisome conservation status. The establishment of management plans for their dwindling populations rely on detailed biological data, including their reproductive ecology. As in the case of numerous other Neotropical palm taxa, small beetles are assumed to be selective pollinators of wax palms, but their identity and relevance in successful fruit yield were unknown. During three consecutive reproductive seasons we collected data on population phenology and reproductive and floral biology of three syntopic species of wax palms native to the Colombian Andes. We also determined the composition of the associated flower-visiting entomofauna, quantifying the extent of the role of individual species as effective pollinators through standardized value indexes that take into consideration abundance, constancy, and pollen transport efficiency. The studied populations of C. parvifrons (Engel) H. Wendl., C. ventricosum Burret, and C. vogelianum (Engel) H. Wendl. exhibit seasonal reproductive cycles with marked temporal patterns of flower and fruit production. The composition of the associated flower-visiting entomofauna, comprised by ca. 50 morphotypes, was constant across flowering seasons and differed only marginally among species. Nonetheless, a fraction of the insect species associated with pistillate inflorescences actually carried pollen, and calculated pollinator importance indexes demonstrated that one insect species alone, Mystrops rotundula Sharp, accounted for 94%–99% of the effective pollination services for all three species of wax palms. The sequential asynchronous flowering of C. parvifrons, C. ventricosum, and C. vogelianum provides an abundant and constant supply of pollen, pivotal for the maintenance of large populations of their shared pollinators, a cooperative strategy proven effective by high fruit yield rates (up to 79%). Reproductive success might be compromised for all species by the population decline of one of them, as it would tamper with the temporal orchestration of pollen offer.


2017 ◽  
Vol 7 (1) ◽  
Author(s):  
Gavin Ballantyne ◽  
Katherine C. R. Baldock ◽  
Luke Rendell ◽  
P. G. Willmer

AbstractAccurate predictions of pollination service delivery require a comprehensive understanding of the interactions between plants and flower visitors. To improve measurements of pollinator performance underlying such predictions, we surveyed visitation frequency, pollinator effectiveness (pollen deposition ability) and pollinator importance (the product of visitation frequency and effectiveness) of flower visitors in a diverse Mediterranean flower meadow. With these data we constructed the largest pollinator importance network to date and compared it with the corresponding visitation network to estimate the specialisation of the community with greater precision. Visitation frequencies at the community level were positively correlated with the amount of pollen deposited during individual visits, though rarely correlated at lower taxonomic resolution. Bees had the highest levels of pollinator effectiveness, with Apis, Andrena, Lasioglossum and Osmiini bees being the most effective visitors to a number of plant species. Bomblyiid flies were the most effective non-bee flower visitors. Predictions of community specialisation (H2′) were higher in the pollinator importance network than the visitation network, mirroring previous studies. Our results increase confidence in existing measures of pollinator redundancy at the community level using visitation data, while also providing detailed information on interaction quality at the plant species level.


Author(s):  
Pat Willmer

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.


2014 ◽  
Vol 86 (1) ◽  
pp. 229-238 ◽  
Author(s):  
TARCILA L. NADIA ◽  
ISABEL C. MACHADO

Rhizophora mangle is considered as a self-compatible mangrove, and is pollinated by wind and insects. However, there is no information about fruit production by autogamy and agamospermy and on the foraging behavior of its flower visitors. Hence, the present study analyzed the pollination and reproductive systems of R. mangle in a mangrove community in northern Pernambuco, Brazil. Floral morphology, sequence of anthesis, and behavior of flower visitors were described; the proportion of flowers that resulted in mature propagules was also recorded. Autogamy, agamospermy, and wind pollination tests were performed, and a new anemophily index is proposed. The flowers of R. mangle are hermaphrodite, protandric, and have high P/O rate. Flies were observed on flowers only during the male phase, probably feeding on mites that consume pollen. Rhizophora mangle is not agamospermic and its fruit production rate by spontaneous self-pollination is low (2.56%) compared to wind pollination (19.44%). The anemophily index was high 0.98, and thus it was considered as a good indicator. Only 13.79% of the flowers formed mature propagules. The early stages of fruit development are the most critical and susceptible to predation. Rhizophora mangle is, therefore, exclusively anemophilous in the study area and the propagule dispersal seems to be limited by herbivory.


2019 ◽  
Vol 152 (1) ◽  
pp. 68-77
Author(s):  
Raphael Matias ◽  
Marco Túlio Furtado ◽  
Silvia B. Rodrigues ◽  
Hélder Consolaro

Background and aims – Hummingbirds are dependent and specialized on nectar-feeding, and many plants depend upon them for pollination. However, the degree of plant-pollinator interdependence varies greatly among species; thus, information on plant mating systems and availability of resources may help to clarify the dependence of interacting organisms. The goals of this study were to (1) quantify the floral resource available during the flowering of Dicliptera squarrosa Nees for comparison with other co-flowering ornithophilous species, and to (2) determine the importance of floral visitors for the reproductive success of this plant.Methods – Data collection was performed in a forest fragment within the urban perimeter of Catalão, Goiás, from September 2012 to August 2013. We investigated the flowering phenology, floral biology, nectar characteristics, flower visitors and mating systems of D. squarrosa. Additionally, we evaluated the amount of floral resource offered (number of flowers and energy in joules) by co-flowering ornithophilous species within an area of 6000 m2 for comparison with D. squarrosa.Key results – Dicliptera squarrosa presents flowers adapted to pollination by hummingbirds, which act as the sole pollinator group for flowers of this species. Flowering occurs from June to September and is synchronous with five other co-flowering species. During the months between July and September, D. squarrosa is the main food source for hummingbirds in the area, offering more floral resources than all of the other five ornithophilous species together. Plants of this species are self-compatible, but they depend on hummingbirds to transfer pollen; levels of autonomous autogamy were low.Conclusions – We suggest that D. squarrosa is an important species for maintaining hummingbirds in the forest fragment due to its high production of nectar resources. In addition, data on floral biology, flower visitors, and mating systems showed the importance of hummingbirds for reproduction of D. squarrosa, suggesting a mutualistic interaction between plant and hummingbirds.


1991 ◽  
Vol 39 (2) ◽  
pp. 167 ◽  
Author(s):  
G Vaughton ◽  
M Ramsey

Stigma receptivity, pollen longevity and rates of flower opening were examined in Banksia spinulosa var. neoanglica. The interaction between these aspects of floral biology and removal of self pollen by floral visitors, autogamous pollen deposition and autogamous fruit set was determined. Flowers were strongly protandrous; most stigmatic grooves opened and maximum stigma receptivity occurred 3-4 days after the flowers opened. Over 80% of pollen was viable when flowers first opened. Pollen longevity was extended; 58% and 33% of pollen was still viable 8 and 12 days respectively after the flowers opened. Rates of flower opening were slow with only 19-32 flowers opening per day, depending on temperature. More than 80% of flowers had self pollen remaining on their pollen presenters 5 days after the flowers opened. Autogamous pollination did not occur until at least 6 days after the flowers opened. Pollen deposition and fruit production were significantly less on autogamous than open-pollinated inflorescences. Pronounced protandry, extended pollen longevity and slow rates of flower opening in B. spinulosa may have been selectively favoured by inefficient removal of self pollen by floral visitors.


2021 ◽  
pp. 1-9
Author(s):  
Khwankhao Sinhaseni ◽  
Carla P. Catterall

Abstract The importance of wild insects as pollinators of tropical tree crops has rarely been tested. Across 18 small-scale lychee orchards in northern Thailand, we evaluated the roles of different wild insects as pollinators and predators of pests in fruit production. Quantitative assessments showed that bees (Family Apidae) were strongly dominant (83%) among insect flower visitors, comprising four species in tribes Apini and four in Meliponini. Experimental manipulations of inflorescences showed that fruit production in these orchards was: (1) dependent on flower visits by wild insects because enclosure of inflorescences in mesh bags decreased fruit set (to one-fifth) and (2) not greatly limited by pollinator deficiencies, because hand pollination of unbagged flowers did not enhance fruit set. Pollination success, as indicated by the proportion of unmanipulated flowers setting fruit, correlated positively across orchards with the abundance of large-bodied Apidae (>7 mm; most were Apis species) and of Apini, and negatively with abundance of small-bodied Apidae and of all Meliponini, despite the latter being the commonest flower visitors. We conclude that larger-bodied bees are most likely to travel sufficiently far to import genetically diverse pollen, in this landscape-scale mosaic where non-orchard habitats (both agriculture and treed patches) were sufficient to sustain wild pollinators.


2017 ◽  
Vol 21 ◽  
Author(s):  
Anna Gorenflo ◽  
Tim Diekötter ◽  
Mark Van Kleunen ◽  
Volkmar Wolters ◽  
Frank Jauker

Biotic pollination is an important factor for ecosystem functioning and provides a substantial ecosystem service to human food security. Not all flower visitors are pollinators, however, and pollinators differ in their pollination performances. In this study, we determined the efficiencies of flower visitors to the plant species Malva sylvestris, Borago officinalis and Onobrychis viciifolia by analysing stigmatic pollen deposition. We further calculated pollinator effectiveness by scaling up single-visit pollen deposition using visitation frequency. Flower-visitor groups differed in their efficiencies at the single-visit level and not all of them deposited more pollen compared to unvisited stigmas. Bumblebees tended to be most efficient in depositing pollen per single visit across the three plant species. Due to the by far highest visitation frequencies, Apis mellifera showed the highest effectiveness in depositing pollen per hour for M. sylvestris and B. officinalis, but not for O. viciifolia, for which the Bombus lapidarius complex was both the most frequent and the most effective pollinator group. Hence, the most frequent flower visitors were most effective in our study. For non-dominant pollinator groups, however, visitation frequencies contributed disproportionally to pollinator effectiveness. Thus, combining pollen deposition per single-visit with visitation frequency is necessary to reveal true pollinator performance and to better understand flower-visitor interactions. 


2018 ◽  
Vol 285 (1870) ◽  
pp. 20172140 ◽  
Author(s):  
Keng-Lou James Hung ◽  
Jennifer M. Kingston ◽  
Matthias Albrecht ◽  
David A. Holway ◽  
Joshua R. Kohn

The western honey bee ( Apis mellifera ) is the most frequent floral visitor of crops worldwide, but quantitative knowledge of its role as a pollinator outside of managed habitats is largely lacking. Here we use a global dataset of 80 published plant–pollinator interaction networks as well as pollinator effectiveness measures from 34 plant species to assess the importance of A. mellifera in natural habitats. Apis mellifera is the most frequent floral visitor in natural habitats worldwide, averaging 13% of floral visits across all networks (range 0–85%), with 5% of plant species recorded as being exclusively visited by A. mellifera . For 33% of the networks and 49% of plant species, however, A. mellifera visitation was never observed, illustrating that many flowering plant taxa and assemblages remain dependent on non- A. mellifera visitors for pollination. Apis mellifera visitation was higher in warmer, less variable climates and on mainland rather than island sites, but did not differ between its native and introduced ranges. With respect to single-visit pollination effectiveness, A. mellifera did not differ from the average non- A. mellifera floral visitor, though it was generally less effective than the most effective non- A. mellifera visitor. Our results argue for a deeper understanding of how A. mellifera , and potential future changes in its range and abundance, shape the ecology, evolution, and conservation of plants, pollinators, and their interactions in natural habitats.


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