Effect of Apis mellifera on community composition of local pollinator bees and their pollination network in Qinling Mountains and surrounding areas

The Qinling Mountains, known for their rich vegetation and diverse pollinating insects, have seen a significant decline in bee species richness and abundance over recent decades, largely due to the introduction and spread of Apis mellifera. This decline has caused cascading effects on the region's community structure and ecosystem stability. To improve the protection of native bees in the natural and agricultural landscape of the Qinling Mountains and its surrounding areas, we investigated 33 sampling sites within three habitats: forest, forest-agriculture ecotones, and farmland. Using a generalized linear mixing model, t-test, and other data analysis methods, we explored the impact of Apis mellifera on local pollinator bee richness, abundance, and the pollination network in different habitats in these regional areas. The results show that(1)Apis mellifera significantly negatively affects the abundance and richness of wild pollinator bees,while Apis cerana abundance is also affected by beekeeping conditions.(2)There are significant negative effects of Apis mellifera on the community structure of pollinator bees in the Qinling Mountains and its surrounding areas: the Shannon-Wiener diversity index, Pielou evenness index, and Margalef richness index of bee communities at sites with Apis mellifera influence were significantly lower than those at sites without Apis mellifera influence.(3)The underlying driver of this effect is the monopolization of flowering resources by Apis mellifera. This species tends to visit flowering plants with large nectar sources, which constitute a significant portion of the local plant community. By maintaining a dominant role in the bee-plant pollination network, Apis mellifera competitively displaces native pollinator bees, reducing their access to floral resources. This ultimately leads to a reduction in local bee-plant interactions, decreasing the complexity and stability of the pollination network. These findings highlight the need for targeted conservation efforts to protect native pollinator species and maintain the ecological balance in the Qinling Mountains.

Species and Diversity Analysis of Flower-visiting Insects of Asian Sacred Lotus in Jiangxi, Hunan and Hubei Provinces

[Objective]This study aimed to investigate the community structure, species and quantities of flower-visiting insects of seed lotus in main producing ar-eas of Jiangxi, Hunan and Hubei provinces. [Method] Using sample area survey and netting method in the fixed points to investigate species and quantities of Asian sacred lotus, the species diversity of different locations was evaluated by diversity indices （H′）, evenness indices （J） and dominant concentration indices （C）. [Result] Apis mel ifera, Apis cerana cerana, Xylocopa （Koptortosoma） sinensis, Xylocopa （s.str.） valga and Xylocopa （Al oxylocopa） appendiculata, al of which belong to order Hy-menoptera were the main pol inators of lotus. Temperature was the main factor which influenced the foraging behaviors of flower-visiting insects. The daily activities of X. （s.str.） valga and X. （Al oxylocopa） appendiculata were bimodal, and that of A. mel-lifera, A. cerana cerana and X. （s.str.） valga were unimodal. The percentage of wild pol inators in Linxiang of Hunan Province and Xianning of Hubei Province were only 20.59% and 3.90% respectively, and there were six species of flower-visiting insects in Linxiang and three in Xianning. The percentages of wild pol inators in Shicheng of Jiangxi Province and the lotus garden in Huazhong Agricultural University were 55.61% and 90.40% respectively, and the flower-visiting insects belonged to 13 and 12 species respectively. The diversity index （H′） and evenness index （J） were listed here in a decreasing order： Shicheng of Jiangxi ＆gt;lotus garden in Huazhong Agricul-tural University＆gt;Linxiang of Hunan ＆gt;Xianning of Hubei. The sequence of dominant concentration indices （C） was Shicheng of Jiangxi ＆lt;the lotus garden in Huazhong Agricultural University＆lt;Linxiang of Hunan＆lt;Xianning of Hubei. The diversity indices （H′）, evenness indices （J） and dominant concentration indices （C） of each sample location were consistent. [Conclusion] The species and quantities of Asian sacred lotus vary in different ecological areas. The species and quantities of Linxiang in Hunan Province and Xianning in Hubei Province are rare. The increase of lotus production must depend on bee pol ination.

The ultraviolet colour component enhances the attractiveness of red flowers of a bee-pollinated plant

Aims Bee-pollinated flowers are rarely red,presumably because bees(which lack red receptors)have difficulty detecting red targets.Although the response of bees to red colour has been investigated in lab experiments,most stimuli have been pure red,while the subtle diversity of red as perceived by humans(human-red)has received very limited attention.Here we test the hypothesis that ultraviolet(UV)reflected from human-red flowers enhances their attractiveness to bees,through increased chromatic contrast.Methods Using Onosma confertum(Boraginaceae),a plant with UV-reflecting red flowers that are pollinated by bumblebees,we investigated the effects of UV reflection on pollinator responses by conducting phenotypic manipulation experiments in the field.Colour preferences of flower-naïve bumblebees were also examined.Colour perception by bumblebees was estimated in terms of chromatic and achromatic contrast,based on two different colour perception models.Important Findings We found that both natural and flower-naïve bumblebees strongly preferred visiting UV-reflecting targets compared with UV-absorbing ones.Colour models show that the UV-reflecting flowers exhibit higher spectral purity and higher chromatic contrast against the foliage background,whereas they have similar achromatic contrast in terms of green receptor contrast.These results indicate that the component of UV reflection increases chromatic contrast in O.confertum,enhancing the visual attractiveness of these red flowers to bumblebees.We further infer that the secondary reflectance might be a necessary component in human-red flowers that are primarily pollinated by animals without red receptors,such as bees.