scholarly journals Variation in Manduca sexta Pollination-Related Floral Traits and Reproduction in a Wild Tobacco Plant

2021 ◽  
Vol 9 ◽  
Author(s):  
Julia Bing ◽  
Xiang Li ◽  
Alexander Haverkamp ◽  
Ian T. Baldwin ◽  
Bill S. Hansson ◽  
...  
Keyword(s):  
Manduca Sexta ◽  
Seed Set ◽  
Tobacco Plant ◽  
The Other ◽  
Floral Traits ◽  
Nicotiana Attenuata ◽  
Pollination Syndromes ◽  
Pollination Services ◽  
Flower Opening ◽  
Local Adaptations

Most flowering plants depend on animal pollination for successful sexual reproduction. Floral signals such as color, shape, and odor are crucial in establishing this (often mutualistic) interaction. Plant and pollinator phenotypes can vary temporally but also spatially, thus creating mosaic-like patterns of local adaptations. Here, we investigated natural variation in floral morphology, flower volatile emission, and phenology in four accessions of a self-compatible wild tobacco, Nicotiana attenuata, to assess how these traits match the sensory perception of a known pollinator, the hawkmoth Manduca sexta. These accessions differ in floral traits and also in their habitat altitudes. Based on habitat temperatures, the accession occurring at the highest altitude (California) is less likely to be visited by M. sexta, while the others (Arizona, Utah 1, and Utah 2) are known to receive M. sexta pollinations. The accessions varied significantly in flower morphologies, volatile emissions, flower opening, and phenology, traits likely important for M. sexta perception and floral handling. In wind tunnel assays, we assessed the seed set of emasculated flowers after M. sexta visitation and of natural selfed and hand-pollinated selfed flowers. After moth visitations, plants of two accessions (Arizona and Utah 2) produced more capsules than the other two, consistent with predictions that accessions co-occurring with M. sexta would benefit more from the pollination services of this moth. We quantified flower and capsule production in four accessions in a glasshouse assay without pollinators to assess the potential for self-pollination. The two Utah accessions set significantly more seeds after pollen supplementation compared with those of autonomous selfing flowers, suggesting a greater opportunistic benefit from efficient pollinators than the other two. Moreover, emasculated flowers of the accession with the most exposed stigma (Utah 2) produced the greatest seed set after M. sexta visitation. This study reveals intraspecific variation in pollination syndromes that illuminate the potential of a plant species to adapt to local pollinator communities, changing environments, and altered pollination networks.

scholarly journals Pollen adaptation to ant pollination: a case study from the Proteaceae

2020 ◽  
Vol 126 (3) ◽  
pp. 377-386 ◽  
Author(s):  
Nicola Delnevo ◽  
Eddie J van Etten ◽  
Nicola Clemente ◽  
Luna Fogu ◽  
Evelina Pavarani ◽  
...  
Keyword(s):  
Seed Set ◽  
Germination Rate ◽  
Pollen Grains ◽  
Relative Effect ◽  
The Other ◽  
Pollen Load ◽  
Pollination Services ◽  
Ant Pollination ◽  
Negative Effect ◽  
Floral Visitors

Abstract Background and Aims Ant–plant associations are widely diverse and distributed throughout the world, leading to antagonistic and/or mutualistic interactions. Ant pollination is a rare mutualistic association and reports of ants as effective pollinators are limited to a few studies. Conospermum (Proteaceae) is an insect-pollinated genus well represented in the south-western Australia biodiversity hotspot, and here we aimed to evaluate the role of ants as pollinators of C. undulatum. Methods Pollen germination after contact with several species of ants and bees was tested for C. undulatum and five co-flowering species for comparison. We then sampled the pollen load of floral visitors of C. undulatum to assess whether ants carried a pollen load sufficient to enable pollination. Lastly, we performed exclusion treatments to assess the relative effect of flying- and non-flying-invertebrate floral visitors on the reproduction of C. undulatum. For this, we measured the seed set under different conditions: ants exclusion, flying-insects exclusion and control. Key Results Pollen of C. undulatum, along with the other Conospermum species, had a germination rate after contact with ants of ~80 % which did not differ from the effect of bees; in contrast, the other plant species tested showed a drop in the germination rate to ~10 % following ant treatments. Although ants were generalist visitors, they carried a pollen load with 68–86 % of suitable grains. Moreover, ants significantly contributed to the seed set of C. undulatum. Conclusions Our study highlights the complexity of ant–flower interactions and suggests that generalizations neglecting the importance of ants as pollinators cannot be made. Conospermum undulatum has evolved pollen with resistance to the negative effect of ant secretions on pollen grains, with ants providing effective pollination services to this threatened species.

scholarly journals Three options are better than two: compensatory nature of different pollination modes in Salix caprea L.

2021 ◽  
Vol 28 ◽  
pp. 75-89
Author(s):  
Kaz Ohashi ◽  
Andreas Jürgens
Keyword(s):  
Seed Set ◽  
Pollen Limitation ◽  
Pollen Viability ◽  
The Other ◽  
Wind Pollination ◽  
Cold Night ◽  
Flower Opening ◽  
Mate Availability ◽  
Salix Caprea ◽  
Moth Pollination

Mixed pollination systems have been reported for many angiosperms. Here, we report on a dioecious willow, Salix caprea L., which employs three pollination modes, namely pollination by wind, nocturnal moths, and diurnal bees. In four field populations of S. caprea in Germany, we addressed the following questions: (a) How are the pollination modes affected by local mate availability? (b) What is the contribution of each pollination mode to seed set? (c) How does flower opening time affect pollination? We compared seed set among seven pollination treatments (wind pollination, diurnal pollination, nocturnal pollination, natural pollination, apomictic reproduction, daytime/night-time artificial pollination). Pollen limitation was observed across populations. On the other hand, limitations in mate availability affected the pollination modes differently. Insect pollination outperformed wind pollination in situations where nearby males were few or all positioned in the same direction from the females. The contribution of nocturnal moths was lower than that of the other pollen vectors. However, moth pollination worked complementarily with bee pollination in compensating for the lack of wind pollination. Furthermore, we found that the onset of flower anthesis peaked at sunset, and that cold night temperatures had no negative effect on seed set or pollen viability. Thus, nocturnal anthesis and prior pollination by moths may minimize male fitness loss due to pollen collection and grooming by bees. We suggest that S. caprea maximizes its fitness by combining multiple pollination modes that work in different environmental conditions, while optimizing the anthesis so that more pollen would be delivered to stigmas. 

scholarly journals How scent and nectar influence floral antagonists and mutualists

eLife ◽  
2015 ◽  
Vol 4 ◽  
Author(s):  
Danny Kessler ◽  
Mario Kallenbach ◽  
Celia Diezel ◽  
Eva Rothe ◽  
Mark Murdock ◽  
...  
Keyword(s):  
Flowering Plants ◽  
Floral Traits ◽  
Nicotiana Attenuata ◽  
Fitness Costs ◽  
Pollination Services ◽  
Nectar Production ◽  
Floral Scents ◽  
Native Habitat ◽  
Native Populations ◽  
Outcrossing Rates

Many plants attract and reward pollinators with floral scents and nectar, respectively, but these traits can also incur fitness costs as they also attract herbivores. This dilemma, common to most flowering plants, could be solved by not producing nectar and/or scent, thereby cheating pollinators. Both nectar and scent are highly variable in native populations of coyote tobacco, Nicotiana attenuata, with some producing no nectar at all, uncorrelated with the tobacco's main floral attractant, benzylacetone. By silencing benzylacetone biosynthesis and nectar production in all combinations by RNAi, we experimentally uncouple these floral rewards/attractrants and measure their costs/benefits in the plant's native habitat and experimental tents. Both scent and nectar increase outcrossing rates for three, separately tested, pollinators and both traits increase oviposition by a hawkmoth herbivore, with nectar being more influential than scent. These results underscore that it makes little sense to study floral traits as if they only mediated pollination services.

Study on floral traits and seed setting in parental lines of hybrid rice during early ahu and kharif seasons

2018 ◽  
Vol 78 (3) ◽  
Author(s):  
Aradhana Phukan ◽  
P. K. Barua ◽  
D. Sarma ◽  
S. D. Deka
Keyword(s):  
Seed Set ◽  
Flag Leaf ◽  
Pollen Dispersal ◽  
Pollen Sterility ◽  
Leaf Length ◽  
Floral Traits ◽  
Opening Angle ◽  
Leaf Angle ◽  
Seed Setting ◽  
Parental Lines

Two CMS lines, IR 58025A and IR 68888A along with their maintainers and two fertility restorers, LuitR and IR 36R, were evaluated for flower and plant characters during early ahu (February-June) and kharif (July-November) seasons. IR 58025A showed longer stigmata and styles, and higher spikelet Length/Breadth (L/B) ratio while IR 68888A showed broader stigmata and wider glume opening angle in both the seasons. IR 68888A also exhibited higher pollen sterility during early ahu. IR 36R was characterized with broad anthers. LuitR showed longer and broader anthers with more pollen than others. Plant height, flag leaf length, flag leaf width and area were higher in IR 36R. Panicle exsertion was complete in pollen parents whereas it was 78-80% in CMS lines. The widest flag leaf angle was found in IR 58025B during early Ahu and in IR 36R during kharif. Kharif season was more favourable for growth of the plants with higher seed set percentage while floral traits of the CMS lines were better expressed in early Ahu. Manipulation of the seeding sequence of the parental lines in early Ahu is warranted for better seed set provided the seed crop escapes heavy premonsoon showers during reproductive stage. IR 68888A/LuitR was a good combination for pollen dispersal and seed setting.

scholarly journals Hawkmoths evaluate scenting flowers with the tip of their proboscis

eLife ◽  
2016 ◽  
Vol 5 ◽  
Author(s):  
Alexander Haverkamp ◽  
Felipe Yon ◽  
Ian W Keesey ◽  
Christine Mißbach ◽  
Christopher Koenig ◽  
...  
Keyword(s):  
Wind Tunnel ◽  
Manduca Sexta ◽  
Ecosystem Service ◽  
Floral Scent ◽  
Nicotiana Attenuata ◽  
Floral Volatiles ◽  
Pollen Transfer ◽  
Olfactory Neurons ◽  
Molecular Analyses ◽  
Choice Tests

Pollination by insects is essential to many ecosystems. Previously, we have shown that floral scent is important to mediate pollen transfer between plants (<xref ref-type="bibr" rid="bib16">Kessler et al., 2015</xref>). Yet, the mechanisms by which pollinators evaluate volatiles of single flowers remained unclear. Here, Nicotiana attenuata plants, in which floral volatiles have been genetically silenced and its hawkmoth pollinator, Manduca sexta, were used in semi-natural tent and wind-tunnel assays to explore the function of floral scent. We found that floral scent functions to increase the fitness of individual flowers not only by increasing detectability but also by enhancing the pollinator's foraging efforts. Combining proboscis choice tests with neurophysiological, anatomical and molecular analyses we show that this effect is governed by newly discovered olfactory neurons on the tip of the moth's proboscis. With the tip of their tongue, pollinators assess the advertisement of individual flowers, an ability essential for maintaining this important ecosystem service.

scholarly journals Why so many flowers? A preliminary assessment of mixed pollination strategy enhancing sexual reproduction of the invasive <i>Acacia longifolia</i> in Portugal

Web Ecology ◽  
2018 ◽  
Vol 18 (1) ◽  
pp. 47-54 ◽  
Author(s):  
Manuela Giovanetti ◽  
Margarida Ramos ◽  
Cristina Máguas
Keyword(s):  
Invasive Plant ◽  
Seed Set ◽  
Pollen Grains ◽  
Striking Difference ◽  
Pollination Syndromes ◽  
Pollination Success ◽  
Relative Contribution ◽  
Acacia Longifolia ◽  
Exclusion Experiments ◽  
Pollination Strategy

Abstract. Acacia longifolia, a native legume from Australia, has been introduced in many European countries and elsewhere, thus becoming one of the most important global invasive species. In Europe, its flowering occurs in a period unsuitable for insect activity: nonetheless it is considered entomophilous. Floral traits of this species are puzzling: brightly coloured and scented as liked by insects, but with abundant staminate small-sized flowers and relatively small pollen grains, as it is common in anemophilous species. Invasion processes are especially favoured when reshaping local ecological networks, thus the interest in understanding pollination syndromes associated with invasive plant species that may facilitate invasiveness. Moreover, a striking difference exists between its massive flowering and relatively poor seed set. We introduced a novel approach: first, we consider the possibility that a part of the pollination success is carried on by wind and, second, we weighted the ethological perspective of the main pollinator. During the flowering season of A. longifolia (February–April 2016), we carried on exclusion experiments to detect the relative contribution of insects and wind. While the exclusion experiments corroborated the need for pollen vectors, we actually recorded a low abundance of insects. The honeybee, known pollinator of acacias, was relatively rare and not always productive in terms of successful visits. While wind contributed to seed set, focal observations confirmed that honeybees transfer pollen when visiting both the inflorescences to collect pollen and the extrafloral nectaries to collect nectar. The mixed pollination strategy of A. longifolia may then be the basis of its success in invading Portugal's windy coasts.

scholarly journals Shifting Nicotiana attenuata 's diurnal rhythm does not alter its resistance to the specialist herbivore Manduca sexta

2016 ◽  
Vol 58 (7) ◽  
pp. 656-668 ◽  
Author(s):  
Jasmin Herden ◽  
Stefan Meldau ◽  
Sang-Gyu Kim ◽  
Grit Kunert ◽  
Youngsung Joo ◽  
...  
Keyword(s):  
Manduca Sexta ◽  
Diurnal Rhythm ◽  
Nicotiana Attenuata ◽  
Specialist Herbivore

The swift parrot Lathamus discolor (Psittacidae), social bees (Apidae), and native insects as pollinators of Eucalyptus globulus ssp. globulus (Myrtaceae)

2004 ◽  
Vol 52 (3) ◽  
pp. 371 ◽  
Author(s):  
A. B. Hingston ◽  
B. M. Potts ◽  
P. B. McQuillan
Keyword(s):  
Eucalyptus Globulus ◽  
Seed Set ◽  
Bombus Terrestris ◽  
Pollination Services ◽  
Social Bees ◽  
Single Flower ◽  
Fitness Benefits ◽  
The Cost ◽  
Effective Pollinator ◽  
Better Than

It has been argued that the production of sufficient nectar to attract bird pollinators would evolve if the fitness benefits accruing from pollination services by birds, compared with insects, outweighed the cost of increased allocation of photosynthate to nectar. This hypothesis implies that the pollination services provided by birds must be considerably better than those provided by insects with which the plant has evolved. Consistent with this, we found that the endangered native swift parrot Lathamus discolor (Shaw) was a very effective pollinator of the native tree Eucalyptus globulus Labill. in Tasmania, facilitating an average of 76% of the maximum possible seed set for open-pollinated flowers in just one visit to a flower, whereas single flower visits by native insects did not facilitate any seed production. Flowers visited once by either species of introduced social bees, the honeybee Apis mellifera L. or the bumblebee Bombus terrestris (L.), produced less than 7% of the maximum possible seed set for open-pollinated flowers. Hence, easily managed social bees appear to be poor substitutes for bird pollinators in commercial seed orchards of this tree. We propose three possible reasons why this largely bird-pollinated tree has not evolved characters that deter insects from removing nectar.

Are diel patterns of nectar production and anthesis associated with other floral traits in plants visited by potential bird and mammal pollinators?

2004 ◽  
Vol 52 (1) ◽  
pp. 87 ◽  
Author(s):  
V. M. Saffer
Keyword(s):  
Western Australia ◽  
Visual Cues ◽  
Floral Traits ◽  
Pollination Syndromes ◽  
Nectar Production ◽  
Diel Patterns ◽  
Pollen Presentation ◽  
Pollination Systems

Plants pollinated predominantly by vertebrates are thought to have suites of floral traits (e.g.�colour, conspicuousness, odour) that favour either birds or mammals, with brightly coloured, conspicuous flowers associated with birds and drab, concealed flowers with non-flying mammals. This study examined two other floral traits, diel patterns of nectar production and pollen presentation (anthesis). It would be expected that these would be nocturnal in putatively mammal-pollinated plants and diurnal in bird-pollinated plants. In four Banksia and two Dryandra species, all known to be visited by honeyeater birds and small marsupials at one site in south-western Australia, there was no clear correspondence between visual cues and diel patterns of resource presentation. This lack of correlation between floral traits does not support the idea of specialised pollination syndromes, but rather is consistent with generalised pollination systems.

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