Favaro Riccardo, Bauer Lisbeth Marie, Rossi Michele, D'Ambrosio Luca, Bucher Edith, Angeli Sergio
Faculty of Science and Technology, Free University of Bozen-Bolzano, Bolzano, Italy.
Laboratorio Biologico, Agenzia Provinciale per l'Ambiente e la Tutela del Clima, Bolzano, Italy.
Front Physiol. 2019 Sep 18;10:1069. doi: 10.3389/fphys.2019.01069. eCollection 2019.
Honeybees closely rely on insect-pollinated plants for their survival. Each forager bee displays a tendency of loyalty toward specific plant species during the many daily foraging flights. Due to the ease of collection, pollen loads have been extensively used as a proxy for detection of pesticide residues. Pollen is the main protein food source for colonies, and its contamination has also been addressed as a reason for the colony losses phenomenon. As honeybees fly over a variable but wide range territory, they might collect pollen from both agricultural, urban and wild environments, also displaying considerable preferences in botanical sources between colonies of the same apiary. It is thus difficult to address the source of the pesticide contamination, when pollen is analyzed as a whole. In the current study, a practical and reliable approach has been proposed to narrow down the source of contamination. Pollen loads have been collected from colonies placed in eight locations over large apple orchard extensions in Trentino-South Tyrol region (Italy), during and 2 weeks after apple blossom. The pollen loads have been separated by the color due to the predominant plant species. On each color group, palynology and multi-residual chemical analyses have been performed in parallel. The pollen hazard quotient (PHQ) was used to estimate the risk to honeybees of each color group and of the total collected pollen. Apple and dandelion pollen were the main portions of the first collection, while a greater variety emerged after the apple blossom. Dandelion was always present in the samples. The frequency and the amount of pesticide residues differed according to the collection periods, the locations and the pollen color groups. The amount of insecticide residues increased after the apple blossom, while no difference between the period was found on fungicide residues. The PHQ values were higher after the blossom due to the insecticide contribution, with highest values of 160,000 and 150,000. The variations within samples did not allow to identify a unique source of contamination, whereas it seems that the pollen from plants outside the agricultural areas has as much residues as the pollen from apple orchards.
蜜蜂的生存高度依赖虫媒植物。每只觅食蜜蜂在每天多次的觅食飞行中都表现出对特定植物种类的忠诚倾向。由于易于采集，花粉负载已被广泛用作检测农药残留的替代物。花粉是蜂群的主要蛋白质食物来源，其污染也被认为是蜂群损失现象的一个原因。由于蜜蜂飞行的区域范围广泛且多变，它们可能会从农业、城市和野生环境中采集花粉，同一蜂场的蜂群在植物来源上也表现出相当大的偏好。因此，当对花粉进行整体分析时，很难确定农药污染的来源。在当前的研究中，提出了一种实用且可靠的方法来缩小污染源。在意大利特伦蒂诺-南蒂罗尔地区的大型苹果园扩展区域的八个地点放置蜂群，在苹果花期及花期后两周收集花粉负载。由于主要植物种类的不同，花粉负载按颜色进行了分离。对每个颜色组同时进行了孢粉学和多残留化学分析。花粉危害商数（PHQ）用于估计每个颜色组以及所收集的总花粉对蜜蜂的风险。苹果和蒲公英花粉是首次采集的主要部分，而苹果花期后出现了更多种类。蒲公英在样本中一直存在。农药残留的频率和数量因采集时期、地点和花粉颜色组而异。苹果花期后杀虫剂残留量增加，而杀菌剂残留量在不同时期没有差异。由于杀虫剂的影响，花期后的PHQ值更高，最高值分别为160,000和150,000。样本内的变化无法确定唯一的污染源，而似乎农业区域外植物的花粉与苹果园花粉的残留量一样多。
