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Flower Visitation (flower + visitation)
Selected AbstractsThe impact of an alien plant on a native plant,pollinator network: an experimental approachECOLOGY LETTERS, Issue 7 2007Martha E. Lopezaraiza, Mikel Abstract Studies of pairwise interactions have shown that an alien plant can affect the pollination of a native plant, this effect being mediated by shared pollinators. Here we use a manipulative field experiment, to investigate the impact of the alien plant Impatiens glandulifera on an entire community of coflowering native plants. Visitation and pollen transport networks were constructed to compare replicated I. glandulifera invaded and I. glandulifera removal plots. Invaded plots had significantly higher visitor species richness, visitor abundance and flower visitation. However, the pollen transport networks were dominated by alien pollen grains in the invaded plots and consequently higher visitation may not translate in facilitation for pollination. The more generalized insects were more likely to visit the alien plant, and Hymenoptera and Hemiptera were more likely to visit the alien than Coleoptera. Our data indicate that generalized native pollinators can provide a pathway of integration for alien plants into native visitation systems. [source] Alternative pollinator taxa are equally efficient but not as effective as the honeybee in a mass flowering cropJOURNAL OF APPLIED ECOLOGY, Issue 5 2009Romina Rader Summary 1. ,The honeybee Apis mellifera is currently in decline worldwide because of the combined impacts of Colony Collapse Disorder and the Varroa destructor mite. In order to gain a balanced perspective of the importance of both wild and managed pollination services, it is essential to compare these services directly, a priori, within a cropping landscape. This process will determine the capacity of other flower visitors to act as honeybee replacements. 2. ,In a highly modified New Zealand agricultural landscape, we compared the pollination services provided by managed honeybees to unmanaged pollinator taxa (including flies) within a Brassica rapa var. chinensis mass flowering crop. 3. ,We evaluate overall pollinator effectiveness by separating the pollination service into two components: efficiency (i.e. per visit pollen deposition) and visit rate (i.e. pollinator abundance per available flower and the number of flower visits per minute). 4. ,We observed 31 species attending flowers of B. rapa. In addition to A. mellifera, seven insect species visited flowers frequently. These were three other bees (Lasioglossum sordidum, Bombus terrestris and Leioproctus sp.) and four flies (Dilophus nigrostigma, Melanostoma fasciatum, Melangyna novae-zelandiae and Eristalis tenax). 5. ,Two bee species, Bombus terrestris and Leioproctus sp. and one fly, Eristalis tenax were as efficient as the honeybee and as effective (in terms of rate of flower visitation). A higher honeybee abundance, however, resulted in it being the more effective pollinator overall. 6. ,Synthesis and applications. Alternative land management practices that increase the population sizes of unmanaged pollinator taxa to levels resulting in visitation frequencies as high as A. mellifera, have the potential to replace services provided by the honeybee. This will require a thorough investigation of each taxon's intrinsic biology and a change in land management practices to ensure year round refuge, feeding, nesting and other resource requirements of pollinator taxa are met. [source] Effects of patch size and density on flower visitation and seed set of wild plants: a pan-European approachJOURNAL OF ECOLOGY, Issue 1 2010Jens Dauber Summary 1.,Habitat fragmentation can affect pollinator and plant population structure in terms of species composition, abundance, area covered and density of flowering plants. This, in turn, may affect pollinator visitation frequency, pollen deposition, seed set and plant fitness. 2.,A reduction in the quantity of flower visits can be coupled with a reduction in the quality of pollination service and hence the plants' overall reproductive success and long-term survival. Understanding the relationship between plant population size and/or isolation and pollination limitation is of fundamental importance for plant conservation. 3.,We examined flower visitation and seed set of 10 different plant species from five European countries to investigate the general effects of plant populations size and density, both within (patch level) and between populations (population level), on seed set and pollination limitation. 4.,We found evidence that the effects of area and density of flowering plant assemblages were generally more pronounced at the patch level than at the population level. We also found that patch and population level together influenced flower visitation and seed set, and the latter increased with increasing patch area and density, but this effect was only apparent in small populations. 5.,Synthesis. By using an extensive pan-European data set on flower visitation and seed set we have identified a general pattern in the interplay between the attractiveness of flowering plant patches for pollinators and density dependence of flower visitation, and also a strong plant species-specific response to habitat fragmentation effects. This can guide efforts to conserve plant,pollinator interactions, ecosystem functioning and plant fitness in fragmented habitats. [source] The impact of an insecticide on insect flower visitation and pollination in an agricultural landscapeAGRICULTURAL AND FOREST ENTOMOLOGY, Issue 3 2010Claire Brittain 1Pesticides are considered a threat to pollinators but little is known about the potential impacts of their widespread use on pollinators. Less still is known about the impacts on pollination, comprising the ecosystem service that pollinators provide to wildflowers and crops. 2The present study measured flower visitation and pollination in an agricultural landscape, by placing potted flowering plants (Petunia sp.) in vine fields sprayed with a highly toxic insecticide (fenitrothion). During two sampling rounds, insect visitors to the petunias were observed and measures of pollination were recorded by counting and weighing seeds. 3In the earlier sampling round, a lower species richness of insect visitors was observed in fields that had received an early application of insecticide. No negative impacts were found from later applications. The results obtained suggest a greater potential harm to insect pollinators and flower visitation as a result of insecticide application early in the season. 4No reduction in pollination was found in fields that received an early insecticide application. Pollination was greater with two insecticide applications between sampling rounds rather than one application. 5In the present study system, insecticide application had a negative effect on pollinators but a possible positive effect on pollination services. In some cases, it may be that actions for conserving biodiversity will not benefit pollination services to all plants. [source] | ||||||||||