Effects Of Grazing On Pollinator Diversity And Visiting Behavior

In natural ecosystem,pollinator diversity is one of the constituent of insect diversity,but its important role is unknown.Due to natural and human disturbance,the diversity of insect in the ecosystem is facing serious loss,which has great influence on the wild plants and the reproduction of the offspring of the crop.In the grassland ecosystem,the species and quantity of herbivores in human activities will affect the grassland plant community,which will indirectly affect the abundance of pollinator and the way of pollination resources.Grazing by livestock is the most economical way to use grassland.Grazing to protect the environment and feeding of infected insects has led to change the diversity of insects and their visit.However,the understanding of the effects of livestock grazing on pollinator is still inadequate.In this study,the meadow steppe was used as the research object to study the effects of grazing methods(cattle grazing,sheep grazing,mixed grazing,no grazing)on the composition of insects,the similarity index,the abundance of pollinator,the number of visits,visiting time and visiting frequency,to reveal the effect of herbivores on insect diversity and flower-visiting behavior.The main results are as follows:(1)Grazing had no significant effect on pollinator diversity,but grazing could change the number of visiting insects(P < 0.05).Cattle grazing significantly reduced the number of visiting insects.Sheep grazing increased the abundance of hymenoptera;cattle grazing reduced the abundance of Diptera;grazing on Lepidoptera degrees have no significant effect;grazing reduced the abundance of Coleoptera(P < 0.05).(2)The number of pollinators change is due to the effect of yellow flowering plant diameter.The abundance of hymenoptera was affected by flowering plant density and the number of flower.The abundance of Diptera was affected by the diameter of Allium senescens and Dianthus chinensis.The abundance of Coleoptera was affected by the cover of plant.(3)Effects of grazing can access behavior of pollinators(P < 0.05).Cattle,sheep grazing increased the number of pollinators visiting time and visiting frequency,reduced visiting time.Mixed grazing increased the behavior of flower visitors.Mixed grazing increased the behavior of Hymenoptera.Cattle,sheep grazing increased the number of Diptera visit times and frequency,reduced visiting time.Cattle grazingincreased the number of Lepidoptera visit times and visiting time,sheep grazing increased visiting frequency.Grazing increased the visiting time of Coleoptera(P <0.05).(4)The number of visit times to insects was affected by purple flowering plants,especially Veronica incana.Visiting time was influenced by yellow flowering plants,especially Chrysanthemum indicum.The response mechanism of different groups of insects to grazing was also significantly different.The behavior of hymenoptera was affected by the number of purple flowers.The number of Diptera visiting times and visiting frequency was affected by the diameter of yellow flower,visiting time was affected by the yellow flower cover.The number of visiting times was affected by the purple flower cover,visiting time was affected by the purple flower density,visiting frequency was affected by the number of purple flowers.The visiting time of Coleoptera was affected by the diameter of flowering plant flowers.In conclusion,large herbivores can affect the abundance of flower visiting insects and the behavior of flower visitors.This study is helpful to formulate reasonable grassland management measures,which is a great significance to the protection of biodiversity and the maintenance of grassland ecosystem ecological service function.