1a. Objectives (from AD-416):
1) Evaluate practical use of honey bees together with Osmia lignaria as a strategy for integrated pollination management; 2) Examine effect of the addition of flowering plants besides almond bloom that provides resources for bee nesting on reproduction and abundance of managed and unmanaged bees.
1b. Approach (from AD-416):
1)Orchards will be pollinated with honey bees alone or with honey bees in addition to Osmia lignaria; nut yields from orchards will be used to assess pollination efficacy of the solo or tandem pollinators; also, visual observations will record behaviors interactions between bee species to assess synergistic effects of bees on each other. 2) Early-blooming plants will be grown between rows of almond trees; their use as alternative post-almond bloom forage for bees in orchards will be measured through assessment of managed bee reproduction (using nest dissections and x-rays) and bee abundance (using surveys) in general; above nut and bee yields will be compared to orchards without additional forage.
3. Progress Report:
Three projects were initiated this year. (1) We initiated the study of pollination of almond orchards with (n = 6) or without (n = 6) Osmia lignaria in the presence of Apis mellifera (honey bees). Only these managed bees were seen during almond bloom in timed observations of 30 marked flowering tree branches located at five increasing distances (approx. 0-100 meters) from the edge of each orchard in which O. lignaria were present and in three of the orchards with only A. mellifera present. Nest boxes (96) containing nest cavities (200/box) were deployed in two 4-hectare sections of each of the 61-hectare orchards where 8,000 O. lignaria were released. About two months after nesting had ceased, the nest boxes were removed from the orchard, and nest cavities were placed into storage. In late summer 2013, nest cavities containing bee cells will be x-radiographed to determine bee offspring number and sex, and nuts from will be sampled from 80 trees in each of the 12 orchards to determine the yields according to presence of pollinators. Also, spring-blooming non-crop plants were planted in Fall 2012 on a plot at Paramount Farming Co. and evaluated for bloom timing and ease of management in Spring 2013. Based on results, some of these plants will be selected for planting alongside or within orchards in subsequent years. Data on the economic inputs of almond and bee production are being gathered. (2) We also quantified the diversities and abundances of bees pollinating commercial bramble fruits (red and black raspberries, blackberries) on five large farms in northwestern Oregon. Apis mellifera predominated at four of the farms (over 90%), but were outnumbered by three species of wild bumble bees on the fifth farm, which had depleted honey bee hives. At no farm did any other native bee represent more than 1% of the pollinators. At none of the farms was there a clear diminution of pollinator abundance with distance from field edge (from 0 to 100 m). Overall, 860 bees were systematically counted at 550 plants. Data on pesticide use is being collected from each grower. Budgetary uncertainties prevented the recruitment of a graduate student for this project this year. (3) We also developed techniques to estimate the number of bumble bee colonies within an area, based on the genetics of adult bees captured in the field. These techniques involve the use of DNA markers that are based on ten microsatellite regions, and can be used to determine whether captured bees belong to the same nest, a method similar to DNA fingerprinting. Monitoring activities include: email communication, telephone and conference calls, discussions at professional meetings, discussions at workshops/conferences, and site visits.