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）蜂箱内储存的食物资源及幼蜂数量的变化。本研究于巴西里奥格兰德州瓦卡里亚市开展，共纳入40群西方蜜蜂，在两个连续的苹果授粉季开展实验。研究人员通过解读野外拍摄的影像记录，分别在授粉期前、授粉期内及授粉结束45天后对蜂群的育虫巢脾进行评估。2014/2015年度，蜂群在被转运至苹果园前，主要在原生林或油菜（Brassica napus）种植区觅食；2015/2016年度，则主要在原生林或桉树（Eucalyptus sp.）人工林区域觅食。两个授粉季中，蜂箱内储存的食物资源（蜂蜜与花粉）占比在授粉前与授粉后阶段均出现显著下降，但授粉期与授粉后阶段之间无显著差异。其中，油菜种植区来源的蜂群食物储存量下降幅度最大——该区域的花类资源供给量远高于苹果园。在苹果园内，对种群数量变化最为敏感的蜂群来自油菜种植区；而食物资源供给较低的区域（原生林与桉树林）来源的蜂群，在苹果园内的种群数量反而出现增长。