Effectiveness of diurnal and nocturnal pollination of two milkweeds

1980 ◽  
Vol 58 (16) ◽  
pp. 1744-1746 ◽  
Author(s):  
Robert I. Bertin ◽  
Mary F. Willson

The relative effectiveness of diurnal and nocturnal pollinators of two milkweed species, Asclepias syriaca and A. vcerticillata, was assessed experimentally and related to patterns of nectar production. Nocturnal pollinators inserted and removed fewer pollinia than diurnal vectors but caused equal pod set, and in A. syriaca, caused greater seed set. We suggest that observed peak nectar production patterns are adaptive in attracting nocturnal pollinators that may be of higher quality than diurnal species. This is one of the first attempts to compare the relative effectiveness of diurnal and nocturnal pollinators of any plant species. The excess of vector visits over that needed to obtain maximum pod set may allow selective abortion and (or) be adaptive in increasing reproductive success through pollinia donation.

Oecologia ◽  
1983 ◽  
Vol 56 (1) ◽  
pp. 121-125 ◽  
Author(s):  
A. K. Southwick ◽  
E. E. Southwick

2017 ◽  
Vol 26 (12) ◽  
pp. 1030 ◽  
Author(s):  
Andrew H. Lybbert ◽  
Justin Taylor ◽  
Alysa DeFranco ◽  
Samuel B. St Clair

Wildfire can drastically affect plant sexual reproductive success in plant–pollinator systems. We assessed plant reproductive success of wind, generalist and specialist pollinated plant species along paired unburned, burned-edge and burned-interior locations of large wildfires in the Mojave Desert. Flower production of wind and generalist pollinated plants was greater in burned landscapes than adjacent unburned areas, whereas specialist species responses were more neutral. Fruit production of generalist species was greater in burned landscapes than in unburned areas, whereas fruit production of wind- and specialist-pollinated species showed no difference in burned and unburned landscapes. Plants surviving in wildfire-disturbed landscapes did not show evidence of pollination failure, as measured by fruit set and seed:ovule ratios. Generalist- and specialist-plant species established in the interior of burned landscapes showed no difference in fruit production than plants established on burned edges suggesting that pollination services are conserved with increasing distance from fire boundaries in burned desert landscapes. Stimulation of plant reproduction in burned environments due to competition release may contribute to the maintenance of pollinator services and re-establishment of the native plant community in post-fire desert environments.


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 110 (6) ◽  
pp. 738-745
Author(s):  
Cairo N Forrest ◽  
David G Roberts ◽  
Andrew J Denham ◽  
David J Ayre

Abstract Clonality may provide reproductive assurance for many threatened plants while limiting sexual reproductive success either through energetic tradeoffs or because clones are self-incompatible. Most stands of the Australian arid-zone plant Acacia carneorum, flower annually but low seed set and an absence of sexual recruitment now suggest that this species and other, important arid-zone ecosystem engineers may have low genotypic diversity. Indeed, our recent landscape-scale genetic study revealed that stands are typically monoclonal, with genets usually separated by kilometers. An inability to set sexually produced seed or a lack of genetically diverse mates may explain almost system-wide reproductive failure. Here, using microsatellite markers, we genotyped 100 seeds from a rare fruiting stand (Middle-Camp), together with all adult plants within it and its 4 neighboring stands (up to 5 km distant). As expected, all stands surveyed were monoclonal. However, the Middle-Camp seeds were generated sexually. Comparing seed genotypes with the single Middle-Camp genotype and those of genets from neighboring and other regional stands (n = 26), revealed that 73 seeds were sired by the Middle-Camp genet. Within these Middle-Camp seeds we detected 19 genotypes in proportions consistent with self-fertilization of that genet. For the remaining 27 seeds, comprising 8 different genotypes, paternity was assigned to the nearest neighboring stands Mallee and Mallee-West, approximately 1 km distant. Ironically, given this species’ vast geographic range, a small number of stands with reproductively compatible near neighbors may provide the only sources of novel genotypes.


2019 ◽  
Vol 305 (5) ◽  
pp. 375-384
Author(s):  
Marina M. Moreira ◽  
Amanda S. Miranda ◽  
Bárbara de Sá-Haiad ◽  
Lygia R. Santiago-Fernandes ◽  
Heloisa A. de Lima

1982 ◽  
Vol 60 (12) ◽  
pp. 2692-2696 ◽  
Author(s):  
Susan G. Carpenter ◽  
Grant Cottam

The phenology and development of southern Wisconsin populations of wild ginseng (Panax quinquefolius L.) are described. In natural forests, ginseng plants grow slowly, and most plants do not reach reproductive maturity until they are at least 8 years old. Ginseng flowers are perfect, but maturity of male and female reproductive parts is separated temporally in each flower. Ginseng individuals are not obligate outcrossers, and the flowers are visited by generalist pollinators. Exclusion of pollinators did not reduce fruit or seed set. Aging techniques usually underestimate age. Number of leaves (plant stage) is a more appropriate indicator of development than is the number of "annual" stem scars on the rhizome. The number of seeds produced by a plant may be predicted from the number of leaves and the leaf area of the largest leaflet. Accurate estimates of the number of ginseng plants in an area can be made by sampling early in the summer. However, projections of survival and reproductive success in a ginseng population must account for mortality and for plants that senesce early in the summer months before producing seeds. We recommend that ginseng harvesting in Wisconsin be allowed only after September 1 to insure that fruits on mature plants are ripe.


2020 ◽  
pp. 1-5
Author(s):  
Kady Diatta ◽  
William Diatta ◽  
Alioune Dior Fall ◽  
Serigne Ibra mbacké Dieng ◽  
Amadou Ibrahima Mbaye ◽  
...  

An ethno-apicultural survey was carried out for the plant species pollinated by honey bees in the green district of Casamance (South Senegal). This survey followed a well-established questionnaire concerning beekeepers in these areas. The listed melliferous flora was made of 61 species either. It’s divided into 58 genera and 30 families though the most represented are in decreasing order Fabaceae with 12 species (19.67%) followed by Rutaceae and Malvaceae with 4 species (6.55% each), Arecaceae, Anacardiaceae, Combretaceae, Gramineae, Myrtaceae, with 3 species (4.91% each), then Chrysobalanaceae, Lamiaceae, Meliaceae and Rubiaceae with 2 species (3.27% each) and then Acanthaceae, Asteraceae, Canabaceae, Verbenaceae, Apocynaceae, Bignoniaceae, Annonaceae, Hymenocardiaceae, Icacinaceae, Lauraceae, Moringaceae, Musaceae, Celastraceae, Rhizophoraceae, Sapindaceae, Sterculiceae, Moraceae, Ochnaceae, with 1 species (1.63% each). Melliferous plants include 47.54% nectariferous plants followed by nectariferous polliniferous plants with 37.70% and finally polliniferous species with 14.75%. This study enabled us to identify eight (08) species with high melliferous value. To enhance the value of these plants, further studies on foraging activity and nectar production will be led to prove their real melliferous potential.


2019 ◽  
Author(s):  
Claudia A. Antinao ◽  
Gastón O. Carvallo ◽  
Beatriz Vergara-Meriño ◽  
Cristian A. Villagra ◽  
Pablo C. Guerrero

Background. Sympatric plant species that share pollinators may have similar mating systems because their floral traits are subject to comparable canalization imposed by pollinators. However, if each sympatric species bears specialized floral morphology, each species may attract different pollinators. Our study aims to describe the pollinator diversity and pollination systems of four taxa of Eriosyce that co-occur in an endangered coastal Mediterranean ecosystem in Central Chile. We took two approaches in our study: we assessed the composition and similarity of flower visitors among taxa, and we characterized the breeding systems to determine dependence on pollinators and self-compatibility. Methods. We performed field observations to characterized pollinators during two consecutive years (2016-2017). Additionally, we performed pollination experiments to elucidate reproductive modes using three treatments: manual cross-pollination, automatic self-pollination, and control (unmanipulated individuals). Results. We observed one bird species (Giant hummingbird Patagona gigas only visiting E. subgibbosa) and 14 bee species (13 natives plus Apis mellifera) visiting cacti of the genus Eriosyce. We observed variation in the similarity of intra-specific pollinator composition between years and among Eriosyce species within the same year. Individuals of E. subgibbosa were visited by less number of species (2016 = 4; 2017 = 2), while E. chilensis (2016 = 4; 2017 = 8), E. chilensis var. albidiflora (2016 = 7; 2017 = 4) and E. curvispina var. mutabilis (2016 = 7; 2017 = 6) were visited by a richest guild of visitors (up to 10 bee species each).Autonomous pollination was unfeasible inE. chilensis, which depend on bees to achieve their reproductive success. Eriosyce subgibbosa, visited mainly by the Giant hummingbird, depends on pollinators to achieve reproductive success. Both E. chilensis var. albidiflora and E. curvispina var. mutabilis were visited by a diverse assemblage of non-social native bees, showing some degree of autonomous pollination and self-compatibility. Discussion. Pollinator diversity analyses showed considerable pollinator differences between the species with ornithophilous flowers (E. subgibbosa) and remain taxa which solely dependent on Apoidea species for pollen transfer. The high diversity of native bees among sympatric Eriosyce may be a caused by their microclimatic differences at spatial (differences among cacti microhabitats) and temporal levels (differences of climatic conditions between August to December when different Eriosyce species bloom). Our study contributes to unveiling the evolutionary mechanisms for pollinator partitioning of sympatric close-related plant species. Furthermore, it improves understanding of threatened species reproductive system and ecological interactions, especially to E. chilensis and E. chilensis var. albidiflora, whose studied populations are the only known for these taxa.


2021 ◽  
Author(s):  
Jan E.J. Mertens ◽  
Lucas Brisson ◽  
Štěpán Janeček ◽  
Yannick Klomberg ◽  
Vincent Maicher ◽  
...  

AbstractButterflies and moths are well-visible flower visitors. Nevertheless, almost no quantification of their role in plant-pollinator interactions exists at a community level, especially from tropical rainforests. Moreover, we have virtually no knowledge on environmental and other factors affecting lepidopteran flower visits.We focused on the role of butterflies and hawkmoths as flower visitors in tropical rainforests of Mount Cameroon, especially on its elevational and seasonal changes. We also analysed their preferences to selected floral traits, with a specific focus on pollination syndromes.We video-recorded flower visitors of 1,115 specimens of 212 plant species (>26,000 recording hrs) along the complete elevational gradient of rainforests in two main seasons, and compared frequencies of flower-visiting lepidopterans to other visitors. We compared characteristics of plant-lepidopteran networks among elevations and seasons, and analysed patterns of selected lepidopteran traits. Finally, we analysed inter-family differences in their floral preferences.Altogether, we recorded 734 flower visits by 80 butterflies and 27 hawkmoth species, representing only ~4% of all 18,439 flower visits. Although lepidopterans visited only a third species, they appeared key visitors of several plants. The most flower visits by lepidopterans were recorded in mid-elevations and dry season, mirroring the general patterns of lepidopteran diversity. The networks showed no apparent elevational or seasonal patterns, probably because of the surprisingly high specialisation of interactions in all networks. Significant non-linear changes of proboscis and forewing lengths were found along elevation, and long-proboscid hesperiid butterflies visited flowers with longer tubes or spurs. Substantial differences in floral preferences were found between sphingids, and papilionid, nymphalid and lycaenid butterflies, revealing importance of nectar production, floral size and shape for sphingids, and floral colour for butterflies.Butterflies and hawkmoths were confirmed as relatively minor visitors of tropical forest flowers, although they seemed crucial for pollination of some plant species. Moreover, the revealed floral preferences and trait-matchings confirmed a potential of some lepidopteran families to drive floral evolution in tropical ecosystems.


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