Food resources and population pattern in Apis mellifera hives used for apple pollination

Abstract: The objective of this work was to evaluate the variations in the stored food resources and in the number of immature bees in Apis mellifera hives used for apple (Malus domestica) pollination. The study was conducted in the municipality of Vacaria, in the state of Rio Grande do Sul, Brazil, with 40 hives, over two consecutive harvests. The evaluations were done in the hive brood frames before, during, and 45 days after a pollination period, by interpreting photographic field records. Before being transported to the orchards, the bees foraged primarily in areas with native forest or canola (Brassica napus) crop, in 2014/2015, and with native forest or eucalyptus (Eucalyptus sp.) reforestation, in 2015/2016. In both harvests, the percentage of food resources (honey and pollen) stored in the hives reduced significantly between the pre- and post-pollination periods, but there was no significant difference between the pollination and post-pollination periods. The greatest reduction in the storage of these resources was observed in the hives from the canola crop, which had a large supply of floral resources compared with the apple orchards. The hives most susceptible to population variations within the apple orchards are those from the canola crop, whereas those from areas with a lower food supply (forest and eucalyptus) show population gains in the apple orchards.摘要：本研究旨在评估用于苹果（Malus domestica）授粉的西方蜜蜂（Apis mellifera）蜂群内储粮资源与未成熟蜂量的变化情况。本研究于巴西南里奥格兰德州瓦卡里亚市开展，共纳入40群蜂，覆盖两个连续采收季。研究通过解析田间拍摄的影像记录，于授粉期前、授粉期内及授粉期结束后45天对蜂群巢脾进行评估。2014/2015采收季，蜂群被转运至果园前主要在原生林或油菜（Brassica napus）种植区采食；2015/2016采收季则主要在原生林或桉树（Eucalyptus sp.）人工林区域采食。两个采收季中，蜂群储粮（蜂蜜与花粉）占比均在授粉前至授粉后阶段出现显著下降，但授粉期与授粉后阶段之间无显著差异。相较于苹果园，油菜种植区的蜂群储粮下降幅度最为显著——该区域蜜源资源供给量远高于苹果园。在苹果园中，蜂群种群数量波动最为显著的是来自油菜种植区的蜂群；而蜜源供给较低的原生林与桉树区域的蜂群，在进入苹果园后其种群数量反而有所增长。