Apis sets record red clover seed: a climatic aberration

作者：Stephen William P^*

来源：Journal of Apicultural Research, 2015, 54(2): 137-143.

DOI：10.1080/00218839.2015.1106778

• red clover
• seed yields
• Trifolium pratense
• Bombus sp.
• Apis mellifera

Western Oregon, USA is one of the better red clover seed-producing areas in the world, having an average yield of 676kg/ha; individual growers report yields of over 1000kg/ha. Bloom normally lasts from late June through to the third week in August in well-managed fields. From late June through the third week of July, Apis mellifera is the predominant pollinator. By early August, Apis is usually displaced by very large populations of workers and males of several species of Bombus, especially B. vosnesenskii Radoszkowski. However, 2009 was unique in that the last 16days in July the max-mean temperature was 35.4 degrees C, with a max of 41.0 degrees C. Apis responded by changing its pollen collection in red clover from +/- 1% in previous years, to 41.5% during the 16days of extreme heat, resulting in a yield of 1045kg/ha in the first 30days of red clover bloom. It is postulated that the extreme heat in that year reduced the turgidity of the clover floret and that the accompanying low humidity increased the sugar content of the nectar, making the floret more accessible and attractive. Reference is made to the parallels between high temperatures and Apis pollination of alfalfa in California, and our observations on red clover in Oregon.

• 出版日期2015-3-15