Pollinator visitation, pollen limitation, and selection on flower size through female function in contrasting habitats within a population of Campanula persicifolia

2006 ◽  
Vol 84 (3) ◽  
pp. 412-420 ◽  
Author(s):  
Vivi-Irèn Hansen ◽  
Ørjan Totland
Keyword(s):  
Seed Production ◽  
Structural Equation ◽  
Pollen Limitation ◽  
Phenotypic Selection ◽  
Flower Size ◽  
Pollinator Visitation ◽  
Pollinator Attraction ◽  
Female Function ◽  
Flower Visitation ◽  
Visitation Rates

We looked at whether flower visitation rates, pollen limitation on seed production, and phenotypic selection on flower size through female function varied across a sharp gradient in light intensity (open meadow vs. forest) within a population of the perennial plant Campanula persicifolia L. (Campanulaceae). Flower visitation rates of putative pollinators were similar in both habitats. Seed number per fruit was strongly pollen limited, with no difference in the magnitude of pollen limitation between the two habitats. This strong pollen limitation set the basis for significant phenotypic selection, through female function, on a trait that probably is important for pollinator attraction: flower size. This was revealed by path analysis and structural equation modelling. The lack of difference in pollen limitation on seed production in the two habitats may be explained by the similarity in flower visitation rates in the two habitats. Moreover, the similarity in pollen limitation in the two habitats probably resulted in a similar magnitude and direction of selection on flower size through female function. Our results suggest that pollen limitation and selection through female function may vary little across space within a popualtion despite large variation in the environmental conditions experienced by plants.

Pollination ecology of the dioecious tree Commiphora guillauminii in Madagascar

2004 ◽  
Vol 20 (3) ◽  
pp. 307-316 ◽  
Author(s):  
Nina Farwig ◽  
Emile F. Randrianirina ◽  
Friederike A. Voigt ◽  
Manfred Kraemer ◽  
Katrin Böhning-Gaese
Keyword(s):  
Plant Species ◽  
Fruit Set ◽  
Pollen Limitation ◽  
Bird Species ◽  
Pollination Ecology ◽  
Floral Display ◽  
Flower Visitation ◽  
Visitation Rates ◽  
Male Flowers ◽  
Female Flowers

In dioecious plant species differences in morphology and resources between female and male flowers can have consequences for flower visitation rates. Female flowers sometimes lack pollen and can be less attractive to pollinators than male flowers. We studied the pollination ecology of the dioecious tree Commiphora guillauminii in a dry deciduous forest in western Madagascar. We recorded floral display, visiting insect species and visitation rates for female and male trees. The results showed that female trees produce significantly larger but fewer flowers per inflorescence than male ones. Number of flowers per tree did not differ between the sexes. During 270 observation-hours we observed 17 insect and two bird species visiting the flowers. Mean visitation rates of male flowers were 6.1 times higher than those of female flowers (1.07 vs. 0.18 visitors per flower h−1). Visitation rates to female and male trees showed similar daily and seasonal patterns. Fruit set (2.9%) was low, which could have been caused by pollinator or pollen limitation. This study suggests that dioecy may pose a risk for fruit set and, potentially, reproductive success for plant species with depauperate pollinator faunas on islands such as Madagascar.

scholarly journals Feeding the enemy: loss of nectar and nectaries to herbivores reduces tepal damage and increases pollinator attraction in Iris bulleyana

2017 ◽  
Vol 13 (8) ◽  
pp. 20170271 ◽  
Author(s):  
Ya-Ru Zhu ◽  
Min Yang ◽  
Jana C. Vamosi ◽  
W. Scott Armbruster ◽  
Tao Wan ◽  
...  
Keyword(s):  
Hengduan Mountains ◽  
Alpine Plant ◽  
Natural Conditions ◽  
Floral Nectar ◽  
Herbivore Damage ◽  
Pollinator Visitation ◽  
Pollinator Attraction ◽  
Sw China ◽  
Visitation Rates ◽  
Herbivore Consumption

Floral nectar usually functions as a pollinator reward, yet it may also attract herbivores. However, the effects of herbivore consumption of nectar or nectaries on pollination have rarely been tested. We investigated Iris bulleyana , an alpine plant that has showy tepals and abundant nectar, in the Hengduan Mountains of SW China. In this region, flowers are visited mainly by pollen-collecting pollinators and nectarivorous herbivores. We tested the hypothesis that, in I. bulleyana , sacrificing nectar and nectaries to herbivores protects tepals and thus enhances pollinator attraction. We compared rates of pollination and herbivory on different floral tissues in plants with flowers protected from nectar and nectary consumption with rates in unprotected control plants. We found that nectar and nectaries suffered more herbivore damage than did tepals in natural conditions. However, the amount of tepal damage was significantly greater in the flowers with protected nectaries than in the controls; this resulted in significant differences in pollinator visitation rates. These results provide the first evidence that floral nectar and nectaries may be ‘sacrificed’ to herbivores, leading to reduced damage to other floral tissues that are more important for reproduction.

scholarly journals Disentangling the path of pollinator attraction in temporarily colored flowers

2020 ◽  
Author(s):  
Samuel Boff ◽  
Jessica Amaral Henrique ◽  
Anna Friedel ◽  
Josué Raizer
Keyword(s):  
Short Distance ◽  
Structural Equation ◽  
Predictor Variable ◽  
Floral Display ◽  
Long Distance ◽  
Pollinator Attraction ◽  
Generalist Species ◽  
Visitation Rate ◽  
Flower Visitors ◽  
Flower Visitation

Abstract Plants may use different strategies to attract pollinators in long distance (e.g. floral display) and in short distance (e.g. ratio between differentially colored flowers) scales. The Verbenaceae Lantana canescens Kunth is a wide spread species in open sites of the Brazilian Pantanal wetland. Individuals of this generalist species can produce a variable number of open inflorescences with yellow and white flowers that are organized in whorls. In this study we tested the hypothesis that increased floral display (long distance attraction) and the ratio between yellow and white flowers (short distance attraction) enhances the number of pollinator species and individuals. We observed flower visitors and calculated floral parameters in 38 plots of 1 m2 each, that contained a varying number of flowering L. canescens individuals. Non-metric multidimensional scaling and Bray-Curtis distances were used to account for flower visitor composition and the relative visitation rate, respectively. We used a structural equation model to test the power of each predictor variable on the visitation rate and a covariance analysis to disentangle the effect of each independent variable on the frequency of plant-pollinator interactions. We found that the number of flower visitors and the visitation rate increased with increasing number of inflorescences. Disentangling long and short distance attraction indicated that the number of inflorescences (per plot) and the number of yellow flowers (yellowing effect) contributed most to flower visitation at long and short distance, respectively.

scholarly journals Polyploidization and sexual dimorphism of floral traits in a subdioecious population of Dasiphora glabra

2020 ◽  
Author(s):  
Lin-Lin Wang ◽  
Na-Cai Yang ◽  
Min-Yu Chen ◽  
Yong-Ping Yang ◽  
Yuan-Wen Duan
Keyword(s):  
Sexual Dimorphism ◽  
Genome Size ◽  
Seed Production ◽  
Flower Size ◽  
Floral Traits ◽  
Pollen Transfer ◽  
Pollinator Visitation ◽  
Dioecious Plants ◽  
Male And Female ◽  
Male Flowers

Abstract Aims Sexual dimorphism is a common trait in plants with sex separation, which could influence female and male functions differently. In a subdioecious population of Dasiphora glabra on the Qinghai-Tibet Plateau, we investigated sexual dimorphism of floral traits and their effects on pollinator visitation, pollen flow and seed production. We also examined differences in genome size of hermaphroditic and dioecious plants. Methods We examined sexual dimorphism in flower number, flower size, and pollen and ovule production in a subdioecious population of D. glabra. We compared pollinator visitation, pollen dispersal, and seed production between sexes. We also examined the genome size of three sex morphs using flow cytometry. Important findings The number of hermaphroditic plants was significantly more than that of male and female plants, and dioecious plants accounted for ca. 40% in the study population. Hermaphroditic plants produced significantly more flowers than male and female plants. Flower size of male flowers was significantly larger than that of female and hermaphroditic flowers. Male flowers did not produce more pollen grains than hermaphroditic flowers, but female flowers produced more ovules than hermaphroditic flowers. Flies were the most frequent flower visitors and preferred large flowers, but their movements between flowers did not show any preference to large flowers. Simulated pollen flows suggested that effective pollen transfer was generally low for both hermaphroditic and male flowers, corresponding to the low seed set of naturally pollinated flowers. DNA contents of male and female plants were ca. four times than those of hermaphroditic plants. These results suggest male and female individuals have undergone polyploidy events and thus are not compatible with hermaphroditic individuals. Sexual dimorphism in floral traits in relation to pollination of dioicous plants might show an advantage in female and male functions, but this advantage is masked largely by low effectiveness of pollen transfer.

Mixed effect of habitat fragmentation on pollinator visitation rates but not on seed production in renosterveld of South Africa

2022 ◽  
Vol 146 ◽  
pp. 48-57
Author(s):  
Sina Juliana Hauber ◽  
Simone Lucia Maier ◽  
Opeyemi Adedoja ◽  
Mirijam Gaertner ◽  
Sjirk Geerts
Keyword(s):  
South Africa ◽  
Habitat Fragmentation ◽  
Seed Production ◽  
Pollinator Visitation ◽  
Mixed Effect ◽  
Visitation Rates

scholarly journals Effectiveness of native nectar-feeding birds and the introduced Apis mellifera as pollinators of the kangaroo paw, Anigozanthos manglesii (Haemodoraceae)

2020 ◽  
Vol 68 (1) ◽  
pp. 14
Author(s):  
Bronwyn M. Ayre ◽  
David G. Roberts ◽  
Ryan D. Phillips ◽  
Stephen D. Hopper ◽  
Siegfried L. Krauss
Keyword(s):  
Apis Mellifera ◽  
Reproductive Output ◽  
Pollen Limitation ◽  
Direct Observations ◽  
Flower Visitation ◽  
Nectar Feeding ◽  
Visitation Rates ◽  
Exotic Insects ◽  
Introduced Honeybee ◽  
Floral Visitors

Plants pollinated by vertebrates are often visited by native and exotic insects foraging for pollen and nectar. We compared flower visitation rates, foraging behaviour, and the contribution to reproduction of nectar-feeding birds and the introduced honeybee Apis mellifera in four populations of the bird-pollinated Anigozanthos manglesii (Haemodoraceae). The behaviour of floral visitors was quantified with direct observations and motion-triggered and hand-held cameras. Pollinator access to flowers was manipulated by enclosure in netting to either exclude all visitors or to exclude vertebrate visitors only. Apis mellifera was the only insect observed visiting flowers, and the most frequent flower visitor, but primarily acted as a pollen thief. Although birds visited A. manglesii plants only once per week on average, they were 3.5 times more likely to contact the anther or stigma as foraging honeybees. Exclusion of birds resulted in 67% fewer fruits and 81% fewer seeds than flowers left open and unmanipulated. Unnetted flowers that were open to bird and insect pollinators showed pollen-limitation and a large variation in reproductive output within and between sites. Although honeybees have been shown to pollinate other Australian plants, compared to birds, they are highly inefficient pollinators of A. manglesii.

scholarly journals Pollinators mediate floral microbial diversity and network under agrochemical disturbance

2020 ◽  
Author(s):  
Na Wei ◽  
Avery L. Russell ◽  
Abigail R. Jarrett ◽  
Tia-Lynn Ashman
Keyword(s):  
Functional Groups ◽  
Anthropogenic Disturbance ◽  
Structural Equation ◽  
Equation Modeling ◽  
Pollinator Visitation ◽  
Microbial Network ◽  
Β Diversity ◽  
The Face ◽  
Managed Ecosystems ◽  
Microbiome Assembly

AbstractHow pollinators mediate microbiome assembly in the anthosphere is a major unresolved question of theoretical and applied importance in the face of anthropogenic disturbance. We addressed this question by linking visitation of diverse pollinator functional groups (bees, wasps, flies, butterflies, beetles, true bugs and other taxa) to the key properties of floral microbiome (microbial α- and β-diversity and microbial network) under agrochemical disturbance, using a field experiment of bactericide and fungicide treatments on cultivated strawberries that differ in flower abundance. Structural equation modeling was used to link agrochemical disturbance and flower abundance to pollinator visitation to floral microbiome properties. Our results revealed that (1) pollinator visitation influenced the α- and β-diversity and network centrality of floral microbiome, with different pollinator functional groups affecting different microbiome properties; (2) flower abundance influenced floral microbiome both directly by governing the source pool of microbes and indirectly by enhancing pollinator visitation; and (3) agrochemical disturbance affected floral microbiome primarily directly by fungicide, and less so indirectly via pollinator visitation. These findings improve the mechanistic understanding of floral microbiome assembly, and may be generalizable to many other plants that are visited by diverse insect pollinators in natural and managed ecosystems.

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