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 ◽  
...  

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.

2006 ◽  
Vol 84 (3) ◽  
pp. 412-420 ◽  
Author(s):  
Vivi-Irèn Hansen ◽  
Ørjan Totland

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.


2019 ◽  
Vol 65 (No. 12) ◽  
pp. 574-580
Author(s):  
Jan Kazda ◽  
Aneta Bokšová ◽  
Martina Stejskalová ◽  
Tomáš Šubrt ◽  
Jan Bartoška ◽  
...  

Currently, the hybrid cultivars are predominant in the cultivation of winter oilseed rape in Europe. Cultivation of hybrid cultivars instead of the traditional line can affect the visitation of pollinators. Beekeepers and farmers claim that hybrid cultivars are not visited by pollinators as much as the line. Ten yellow and one white flowering oilseed rape cultivars were used to compare the visitation rates of pollinators (Apis mellifera L. and Bombus sp.) during flowering in the years 2015–2017. At the same time, the visitation of hybrid and line cultivars by pollinators was evaluated. Visitation of pollinators on each cultivar was calculated from observed visitations to flowering oilseed rape plants in an area 2.1 m<sup>2</sup> from the edge of single plots for 20 s. The results from this study clearly show that the individual cultivars, whether hybrids or lines, did not have a major influence on the pollinators’ visitation, either by honey bees or bumble bees. It is thus proved that hybrid cultivars do not affect the pollinator visitation and there is no need to worry about the prevalence of these cultivars in the Czech fields. However, a more significant effect for both pollinator groups appears to have been the color of the flower.


1993 ◽  
Vol 71 (8) ◽  
pp. 1072-1079 ◽  
Author(s):  
Ørjan Totland

Pollination studies in European alpine communities are few. The objective of this study was to describe the pollination ecology in two alpine plant communities at Finse, southwestern Norway. Because of late snowmelt and early winter at Finse, the time available for flowering and seed maturation is restricted. Flowering was concentrated at the beginning of the season in both communities, and large overlaps in flowering time were found for most species. In one of the communities, flowering peaks were significantly clumped, whereas in the other they were randomly distributed through the season. However, in this community, five insect-pollinated species flowered simultaneously early in the season. Diptera almost exclusively dominated the visitor assemblage. Most plant species pairs had high overlaps in flower visitor species. Species flowering simultaneously attracted the same visitor species. In one community, eight species pairs flowered sequentially and shared visitors. Visitation rates were highest at the lowest elevated site. The results are compared with those obtained in other alpine areas. It is argued that selection for an early flowering is probably stronger than selection pressures resulting from interspecific interactions. Key words: alpine, Diptera, flowering phenology, flower visitors, season length, visitation rate.


Caryologia ◽  
2014 ◽  
Vol 67 (3) ◽  
pp. 238-249 ◽  
Author(s):  
Ying Meng ◽  
Yong-Ping Yang ◽  
Hang Sun ◽  
Tao Deng ◽  
Ze-Long Nie

Alpine Botany ◽  
2012 ◽  
Vol 122 (2) ◽  
pp. 65-73 ◽  
Author(s):  
De-Li Peng ◽  
Zhi-Qiang Zhang ◽  
Bo Xu ◽  
Zhi-Min Li ◽  
Hang Sun

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