Montana's Huckleberry (Vaccinium globulare) Mystery: Pollinators, Pests, and Potential Threats
Insects were collected from the V. globulare plants each field season beginning as soon as the flowers opened and continuing until the fruit was ripe. Insects sampled from different parts of the plant (i.e. flowers, leaves and stems, and fruit) were kept in separate vials.
Insects were individually collected between 0900 and 1600 h using a net, aspirator, or Bioquip® insect vacuum, depending on the type of insect. A beating sheet and sweep net were used to sample less visible insects from the plants’ leaves and stems. Bees were placed in a killing jar with ethyl acetate, while other insects were placed in vials of 70% ethyl alcohol. Lepidoptera larvae found feeding on plants were collected, along with V. globulare foliage, to be reared in the lab.
All insects were taken to the MTEC at Montana State University (MSU) where they were cleaned, pinned, labeled, given a unique identifier (barcode), and uploaded to the MTEC X:BioD Database managed by The Ohio State University. Diptera specimens were chemically dried with hexamethyldisilizane (HMDS) following the online protocol of the California State Collection of Arthropods (Orozco and Gaimari 2015). Specimens were identified to the lowest taxon possible, using current literature and the help of experts, and sorted into one of three categories: flower visitors, leaf and stem visitors, and fruit visitors.
Lepidoptera larvae were reared on V. globulare leaves collected at the study sites. The leaves and larvae were placed in plastic bags, kept in the lab at room temperature, and checked at least every other day for the emergence of adults. Adults that emerged were preserved in a freezer until they could be pinned, spread, labeled, and identified.
Pan traps (355ml (12 oz) Solo® plastic bowls) were set up along the periphery of each study site during V. globulare anthesis in order to establish the overall community of bees for comparison. In 2014, yellow pan traps were set up 3 m apart in a linear transect along the edge of each study site. In 2015, four colors of pan traps (yellow, blue, pink, and white) were set up along the edge of each study site in a Latin Square design with 3 m between each bowl.
Red Solo® Cup Traps
Following the protocol established by the University of New Hampshire Cooperative Extension (2014), 532ml (18 oz) red Solo® cup traps were placed at seven study sites in 2014 and four study sites in 2015 to monitor for the presence of D. suzukii. These traps were established as the fruit was beginning to ripen with samples collected each week until the end of the field season.
In 2015, damaged and undeveloped berries were collected from the plants and brought back to the MTEC lab for dissection. Berries were kept in closed petri dishes in a walk-in cooler at approximately 4°C until they could be dissected.
All specimen records were uploaded to the MTEC XBio:D database. Data were then extracted from the database into Excel® for analysis.
This study was observational in nature with the goal of surveying insects associated with the V. globulare plants. Sampling times and methodology were not standardized across all site visits over the two years, preventing quantitative analysis of diversity and abundance. Nevertheless, the data collected can begin to provide insights into the insects associated with the plant, and provides a foundation for further research.