Presentation Type

Poster

Start Date

4-5-2022 11:00 AM

End Date

4-5-2022 1:00 PM

Subjects

Native Bees, Population Survey, Floral Usage

Advisor

Susan Masta

Student Level

Undergraduate

Abstract

There have been few studies of the diversity of bee species found in Oregon’s urban areas, and fewer studies that have systematically examined how bee populations change over the seasons. A survey of native bee populations at the Leach Botanical Gardens was conducted to determine what bees were present, how they changed over the season, and what flowers they used. Biweekly over the 2020 and 2021 bee seasons, sections of the garden were sampled in 30 minute equal time intervals, divided among the patches of flowering plants on which bees were observed. Bee specimens were captured with collection vials on flowers, and by netting. Field sampling was conducted in warm, sunny weather to maximize the number of active bees on flowers. Specimens were euthanized, identified, and recorded with their collection information. Fifteen genera were found. The most frequently captured genera were Ceratina, Osmia, Lasioglossum, Agapostemon, and Melissodes. The first two were most abundant before early June, and the latter three were the dominant bees from mid-summer through autumn. Ceratina and Lasioglossum were present for most of the season. Almost all bee genera were flower generalists, utilizing multiple plant species. In general, native and invasive flowering plants were more utilized than ornamental plants. This study provides a better understanding of the bee populations in the garden, in urban Portland, and lays the groundwork for future surveys.

Persistent Identifier

https://archives.pdx.edu/ds/psu/37503

Included in

Biology Commons

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May 4th, 11:00 AM May 4th, 1:00 PM

Survey of the Bees and Floral Use at the Leach Botanical Garden

There have been few studies of the diversity of bee species found in Oregon’s urban areas, and fewer studies that have systematically examined how bee populations change over the seasons. A survey of native bee populations at the Leach Botanical Gardens was conducted to determine what bees were present, how they changed over the season, and what flowers they used. Biweekly over the 2020 and 2021 bee seasons, sections of the garden were sampled in 30 minute equal time intervals, divided among the patches of flowering plants on which bees were observed. Bee specimens were captured with collection vials on flowers, and by netting. Field sampling was conducted in warm, sunny weather to maximize the number of active bees on flowers. Specimens were euthanized, identified, and recorded with their collection information. Fifteen genera were found. The most frequently captured genera were Ceratina, Osmia, Lasioglossum, Agapostemon, and Melissodes. The first two were most abundant before early June, and the latter three were the dominant bees from mid-summer through autumn. Ceratina and Lasioglossum were present for most of the season. Almost all bee genera were flower generalists, utilizing multiple plant species. In general, native and invasive flowering plants were more utilized than ornamental plants. This study provides a better understanding of the bee populations in the garden, in urban Portland, and lays the groundwork for future surveys.