Pollination and reproductive success in the gynodioecious endemic Thymus loscosii (Lamiaceae)

2005 ◽  
Vol 83 (2) ◽  
pp. 183-193 ◽  
Author(s):  
Maria Renée Orellana ◽  
Anna Maria Rovira ◽  
Cèsar Blanché ◽  
Maria Bosch
Keyword(s):  
Reproductive Success ◽  
Seed Quality ◽  
Seed Set ◽  
Pollen Deposition ◽  
Pollinator Visitation ◽  
Heterospecific Pollen ◽  
Pollen Loads ◽  
Visual Attraction ◽  
Insect Exclusion ◽  
Two Populations

Sexual dimorphism can have implications in the reproductive biology of gynodioecious species, affecting sex fitness. We explored the effects of flower sex on pollination visitation rates and pollinator efficiency in terms of stigmatic pollen loads, as well as on quantitative and qualitative aspects of reproductive success in two populations of Thymus loscosii Willk. (Lamiaceae) endemic to the northeastern Iberian Peninsula. We also assessed the dependence of T. loscosii on insect pollination in both hermaphrodite and female plants by performing an insect exclusion test. Apis mellifera and different species of Bombylidae were the most frequent pollinators (68% of approaches to studied plots and 93% of total visited flowers). Hermaphrodite plants received more visits than female ones, possibly as a response to visual attraction, since flowers of the former are larger. Conspecific pollen deposition was higher on stigmas of hermaphrodite flowers than on those of females; in contrast, female stigmas received more heterospecific pollen loads, notably higher in one population. Despite these differences, seed set from open-pollinated flowers was similar in both sexes and in both populations, and relatively low (around 0.5–1 nutlet per fruiting calyx, on average). Thymus loscosii is self-compatible as it was able to produce seeds by spontaneous selfing, but at very low rates, indicating that it is insect-dependent for pollination. In addition, bagged female flowers also set seeds formed by apomitic mechanisms. In general, seeds from females were slightly heavier and began to germinate earlier and at higher rates than those from hermaphrodites, even those formed by apomixis. These results suggest that female plants enjoy a resource allocation advantage that allows increased seed quality and contributes to the maintenance of gynodioecy.Key words: gynodioecy, pollinator visitation, pollen loads, seed set, sex fitness, Thymus loscosii.

Heterospecific pollen deposition is positively associated with reproductive success in a diverse hummingbird‐pollinated plant community

Oikos ◽  
2021 ◽  
Author(s):  
Sabrina Aparecida Lopes ◽  
Pedro Joaquim Bergamo ◽  
Steffani Najara Pinho Queiroz ◽  
Jeff Ollerton ◽  
Thiago Santos ◽  
...  
Keyword(s):  
Reproductive Success ◽  
Plant Community ◽  
Pollen Deposition ◽  
Heterospecific Pollen ◽  
Heterospecific Pollen Deposition

scholarly journals Floral herbivory does not reduce pollination-mediated fitness in shelter rewarding Royal Irises

2017 ◽  
Author(s):  
Mahua Ghara ◽  
Christina Ewerhardy ◽  
Gil Yardeni ◽  
Mor Matzliach ◽  
Yuval Sapir
Keyword(s):  
Fruit Set ◽  
Seed Set ◽  
Pollen Grains ◽  
Reproductive Organs ◽  
Pollen Grain ◽  
Lower Number ◽  
Pollen Deposition ◽  
Pollination Services ◽  
Pollinator Visitation ◽  
Direct Damage

ABSTRACTFlorivory, the damage to flowers by herbivores can affect fitness both directly and indirectly. Flowers consumed by florivores may fail to produce fruit or produce lower seed set because of direct damage to reproductive organs. In addition, eaten flowers are less attractive to pollinators because of reduced or modified advertisement, which reduces pollination services. While observational data are abundant, experimental evidence is scarce and results are contrasting. We tested experimentally the effect of florivory on both pollinator visitation and reproductive success in three species of the Royal Irises, which have large flowers that are attractive to pollinators, and potentially also for florivores. We hypothesized that florivory will reduce pollen deposition due to reduced attractiveness to pollinators, while fruit set and seed set will depend on the extent of florivory. We performed artificial florivory in two experiments over two years. In the first experiment, each of the three floral units of a single Iris flower was subject to either low or high artificial florivory, or left un-touched as control. We counted the number of pollen grains deposited on each of the three stigmas as a measure of pollinator visitation. In the second experiment, three flowers of the same plant received low, high, or no artificial florivory and were further recorded for fruit and seed production. In 2016, high artificial florivory revealed lower number of pollen grains on stigmas of Iris atropurpurea, but in 2017 there was no difference. Similarly, number of pollen grains in high artificial was lower than low florivory in 2017 in I. petrana. No significant effect of florivory was found on pollen grain deposition, fruit set or seed set. The results remained consistent across species and across years. The results undermine the assumption that flower herbivory is necessarily antagonistic interaction and suggests that florivores may not be strong selection agents on floral reproductive biology in the Oncocyclus irises.

scholarly journals Habitat partitioning in native Geranium species through reproductive interference

2020 ◽  
Vol 125 (4) ◽  
pp. 651-661
Author(s):  
Sachiko Nishida ◽  
Koh-Ichi Takakura ◽  
Akiyo Naiki ◽  
Takayoshi Nishida
Keyword(s):  
Environmental Conditions ◽  
Seed Set ◽  
Low Fertility ◽  
Reproductive Interference ◽  
Small Scale ◽  
Canopy Openness ◽  
Pollen Deposition ◽  
Heterospecific Pollen ◽  
Focal Species ◽  
Putative Hybrids

Abstract Background and Aims Heterospecific pollen transfer may reduce the fitness of recipient species, a phenomenon known as reproductive interference. A theoretical study has predicted that distributions of species pairs affected by reproductive interference may be syntopic under negligible reproductive interference, sympatric but with partitioning at small spatial scale (i.e. allotopic) under weak interference, or exclusive when reproductive interference is strong. Verifying these predictions is essential for evaluation of the applicability of reproductive interference as a general assembly rule of biological communities. The aim of this study was to test these predictions in two sympatrically distributed wild Geranium species, G. thunbergii and G. wilfordii. Methods To measure the effect of reproductive interference, the associations between the relative abundance of the counterpart species and seed set in the focal species, and seed set reduction following mixed pollination, were analysed. The possibility of hybridization with viable offspring was examined by genotyping plants in the field and after mixed pollination. Fertility of putative hybrids was based on their seed set and the proportion of pollen grains with apertural protrusions. A transect study was conducted to examine spatial partitioning, and possible influences of environmental conditions (canopy openness and soil moisture content) on partitioning between the species were analysed. Key Results Neither abundance of the counterpart species nor heterospecific pollen deposition significantly affected seed set in the focal species, and hybridization between species was almost symmetrical. Putative hybrids had low fertility. The two species were exclusively distributed at small scale, although environmental conditions were not significantly different between them. Conclusions The allotopy of the two species may be maintained by relatively weak reproductive interference through bidirectional hybridization. Re-evaluation of hybridization may allow ongoing or past reproductive interference to be recognized and provide insight into the distributional relationships between the interacting plants.

scholarly journals Heterospecific pollen deposition inDelphinium barbeyi: linking stigmatic pollen loads to reproductive output in the field

2015 ◽  
pp. mcv175 ◽  
Author(s):  
Heather M. Briggs ◽  
Lucy M. Anderson ◽  
Laila M. Atalla ◽  
André M. Delva ◽  
Emily K. Dobbs ◽  
...  
Keyword(s):  
Reproductive Output ◽  
Pollen Deposition ◽  
Heterospecific Pollen ◽  
Pollen Loads ◽  
Heterospecific Pollen Deposition

scholarly journals Structural anther mimics improve reproductive success through dishonest signalling that enhances both attraction and the morphological fit of pollinators with flowers

2021 ◽  
Author(s):  
Ethan L Newman ◽  
Katharine L Khoury ◽  
Sandy E Van Niekerk ◽  
Craig I Peter
Keyword(s):  
Reproductive Success ◽  
Seed Set ◽  
Three Dimensional ◽  
Pollen Deposition ◽  
Female Reproductive Success ◽  
Pollinator Attraction

Numerous studies have identified traits associated with pollen mimicry, however, the processes underlying floral deception remains poorly documented for these structures. We studied the importance of attraction and mechanical fit of anther mimics in Tritonia laxifolia (Iridaceae) and their relative contributions to reproductive success. To determine anther mimics role in pollinator attraction, we offered bees binary preferences to flowers painted with UV absorbent and reflecting paint. We also conducted preference experiments between flowers with excised anther mimics and unmanipulated controls, from which mechanical fit was assessed using single visits. Anther mimics effects on female reproductive success was determined using similar treatments, but on rooted plants. Bees preferred UV absorbent over UV reflecting anther mimics. Preference for flowers with and without the three-dimensional structures was equal. Single visits resulted in more pollen deposition on unmanipulated controls over flowers with their anther mimics excised, which was directly linked to pollen-collecting behaviour. Controls with unmanipulated anther mimics experienced more seed set than those with their anther mimics excised. This study provides insights into pollinator-mediated selection on deceptive floral signals and shows that three-dimensional anther mimics increases reproductive success through both attraction, and pollen collecting behaviours that improve the fit between flowers and pollinators.

scholarly journals Comparative effects of pollen limitation, floral traits and pollinators on reproductive success of Hedysarum scoparium Fisch. et Mey. in different habitats

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Min Chen ◽  
Xue-Yong Zhao ◽  
Xiao-An Zuo ◽  
Shao-Kun Wang ◽  
Hao Qu ◽  
...  
Keyword(s):  
Reproductive Success ◽  
Seed Set ◽  
Pollen Limitation ◽  
Positive Association ◽  
Floral Traits ◽  
Limiting Factor ◽  
Pollinator Visitation ◽  
Open Flower ◽  
Visitation Frequency ◽  
The Difference

Abstract Background Reproduction in most flowering plants may be limited because of the decreased visitation or activity of pollinators in fragmented habitats. Hedysarum scoparium Fisch. et Mey. is an arid region shrub with ecological importance. We explored the pollen limitation and seed set of Hedysarum scoparium in fragmented and restored environments, and examined whether pollen limitation is a significant limiting factor for seed set. We also compared floral traits and pollinator visitation between both habitats, and we determined the difference of floral traits and pollinators influenced reproductive success in Hedysarum scoparium. Results Our results indicated that supplementation with pollen significantly increased seed set per flower, which is pollen-limited in this species. Furthermore, there was greater seed set of the hand cross-pollination group in the restored habitat compared to the fragmented environment. More visits by Apis mellifera were recorded in the restored habitats, which may explain the difference in seed production between the fragmented and restored habitats. Conclusions In this study, a positive association between pollinator visitation frequency and open flower number was observed. The findings of this study are important for experimentally quantifying the effects of floral traits and pollinators on plant reproductive success in different habitats.

scholarly journals Quantitative importance of staminodes for female reproductive success in Parnassia palustris under contrasting environmental conditions

2003 ◽  
Vol 81 (1) ◽  
pp. 49-56 ◽  
Author(s):  
Sylvi M Sandvik ◽  
Ørjan Totland
Keyword(s):  
Reproductive Success ◽  
Seed Set ◽  
Plant Traits ◽  
Female Reproduction ◽  
Female Reproductive Success ◽  
Pollinator Visitation ◽  
Visitation Rate ◽  
Pollinator Visitation Rate ◽  
Insect Activity ◽  
Pollination Strategy

The five sterile stamens, or staminodes, in Parnassia palustris act both as false and as true nectaries. They attract pollinators with their conspicuous, but non-rewarding tips, and also produce nectar at the base. We removed staminodes experimentally and compared pollinator visitation rate and duration and seed set in flowers with and without staminodes in two different populations. We also examined the relative importance of the staminode size to other plant traits. Finally, we bagged, emasculated, and supplementary cross-pollinated flowers to determine the pollination strategy and whether reproduction was limited by pollen availability. Flowers in both populations were highly dependent on pollinator visitation for maximum seed set. In one population pollinators primarily cross-pollinated flowers, whereas in the other the pollinators facilitated self-pollination. The staminodes caused increased pollinator visitation rate and duration to flowers in both populations. The staminodes increased female reproductive success, but only when pollen availability constrained female reproduction. Simple linear regression indicated a strong selection on staminode size, multiple regression suggested that selection on staminode size was mainly caused by correlation with other traits that affected female fitness.Key words: staminodes, insect activity, seed set, spatial variation, Parnassia palustris.

Factors affecting pollinator visitation and reproductive success in Sonneratia caseolaris and Aegiceras corniculatum in a mangrove forest in India

2001 ◽  
Vol 17 (3) ◽  
pp. 431-447 ◽  
Author(s):  
SHALINI PANDIT ◽  
B. C. CHOUDHURY
Keyword(s):  
Reproductive Success ◽  
Mangrove Forest ◽  
Time Of Day ◽  
Pollinator Visitation ◽  
Aegiceras Corniculatum ◽  
Factors Affecting ◽  
Plant Reproductive Success ◽  
Sonneratia Caseolaris ◽  
Exclusion Experiments ◽  
Selfing Species

Pollinator visitation to, and the reproductive success of, Sonneratia caseolaris (Sonneratiaceae) and Aegiceras corniculatum (Myrsinaceae) was investigated in a mangrove forest in India. S. caseolaris was shown to be primarily outcrossed and A. corniculatum was shown to be a selfing species. The flowers of both plant species attracted several diurnal and nocturnal visitors. Earlier reports had indicated that S. caseolaris flowered for one night and was exclusively night-pollinated. But flowers of this species were found to be in bloom both at night and during the day, and diurnal visitors to the flowers were more diverse and frequent than nocturnal ones. This was related to the higher volume and energy value of nectar in the morning. The effects of time of day and temperature on visitation rates were quantified. The importance of visitors to plant reproductive success was investigated via controlled visitor-exclusion experiments. Pollinators were expected to be more important for the outcrossing species than for the selfing species, and this was confirmed by the results of the exclusion experiments. In S. caseolaris reproductive success was determined both by pollinator availability and the intensity of flower and fruit predation, while in A. corniculatum it is likely to be resource limited.

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