Project Number: 2080-21000-017-14-A
Project Type: Cooperative Agreement
Start Date: Nov 1, 2017
End Date: Jan 31, 2020
1. Determine the variation in developmental phenology of regional populations of blue orchard bees (BOBs) by maintaining regionally-specific bees under managed or unmanaged conditions. 2. Determine the heritability of regional phenology traits for BOBs from California and Utah by examining population crosses in controlled experiments. 3. Determine the difference in the retention of females between California and Utah BOBs used as pollinators in regions outside of their geographic origin by examining the dispersal and flight range of these populations in cherry orchards in regionally distinct environments.
In 2018, wild-trapped BOB nests from California, Utah and Washington will be shipped to Logan, Utah. Nest cells will be divided into 2 treatment groups from each of the 3 sources so that 200 cells represent each region and treatment. For the “unmanaged” treatment group, cells will be held in growth chambers programmed to mimic temperature cycles of the climates of their origin. For the “managed” treatment, cells will be kept at a constant 26°C. Each cell will be visually inspected daily to record developmental stages. Once cocooned, bees will be x-rayed to record pupal and adult stages. 30 days after reaching adult stage, managed bees will be managed for wintering. The unmanaged group will remain at fluctuating temperatures. In March/April, half of the adults from each treatment will be incubated at 22ºC, and the other half will remain unmanaged to emerge naturally. The length of each developmental stage, time to emergence, duration of emergence period, and weight of adults for each group of bees will be measured. Mortality also will be recorded for all developmental stages. Generalized linear mixed models will be performed look for the effects of native region and treatment on 1) developmental parameters for immature and adult bees, and 2) parameters concerning adult survival and duration of emergence period. To determine any consequences pairing of bees from regionally-distinct localities performance, we will monitor nesting behavior and reproductive output of mixed populations of first generation bees from California and Utah in a controlled experiment. In March/April 2018, reciprocal crosses of the target populations and crosses of same source populations will be orchestrated in large screen cages erected over forage planted in California. We will monitor uniquely-marked females to document their nesting activity and progeny production. Completed nests will be removed and be shipped to the Pollinating Insect-Biology Management, Systematics Research Unit (PIRU). At PIRU, offspring will be reared at ambient California temperatures to record all developmental stages through adulthood and to manage offspring over the winter. In 2019, we will assess the survival of offspring through adult emergence and record adult weight. We also will determine the time until first adult emergence, peak of emergence, and duration of the emergence period. Progeny will be allowed to reproduce in field cages for collection of reproductive success data. Nesting behavior and reproduction of individual females within and between treatments will be compared with generalized linear mixed models for 1) parameters concerning female activities and reproductive success, and 2) parameters concerning progeny development, weight, and reproductive success. To measure BOB establishment by source population and management, wild-trapped bees from Utah and California will be introduced to cherry orchards in both source and reciprocal states. Prior to incubation, loose cocoons will be dusted with both egg white protein powder and a fluorescent marker so that emerging females will contaminate themselves with these markers