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Abstract Detail

Symbioses: Plant, Animal, and Microbe Interactions

Theiss, Kathryn [1], Aranda, Ashley [1], Lara, Magdalena [2], Martinez, Sydney [1], Tafoya, Diana [1], Kram, Karin [1].

Reproductive ecology of Asclepias curassavica in Los Angeles.

Pollinators are critical for the protection of biodiversity, food production, and resilience to global change. Populations of native pollinators have drastically declined, as the resources that they exploit are becoming scarce across the landscape, particularly in areas converted to agriculture and rangelands. As the landscape becomes more urbanized, the built environment has the potential to become an important resource for insect pollinators. Floral and pollinator diversity across the built environment varies at multiple scales, from localized backyards and urban gardens to broad scales across the full urbanization gradient. The floral diversity within the urban environment typically contains both native and non-native species and mon-native species may extend the availability of important pollinator resources such as nectar on a temporal basis, altering pollinator behavior. We focused on the reproductive ecology of the tropical milkweed, Asclepias curassavica, in botanic gardens within the urban matrix of Los Angeles. At our least urban site, we observed floral visitors throughout the flowering season and examined pollinia loads across the most common visitors. The European honeybee, Apis mellifera, dominated the floral visitors with the monarch butterfly, Danaus plexippus, being the second most abundant visitor. Many other species visited the flowers occasionally, including Anna’s hummingbird. However, only A. mellifera was found to remove and insert pollinia in numbers sufficient to propagate this species by seed. Preliminary work demonstrated that milkweeds also host microbial communities within their floral nectar. In other systems, nectar-inhabiting microorganisms can attain high densities and influence nectar characteristics. In milkweeds, the composition of nectar-inhabiting microorganisms and its drivers, which may influence pollination, have not been studied. We compared microbial diversity across three botanic gardens within the Los Angeles Basin that span the urbanization gradient. We collected nectar from ~30 individuals of A. curassavica from each botanic garden and sampled the microbiome using 16S rRNA for bacteria and ITS for yeast. We found high variation in our bacterial species across all samples, but comparatively low yields for yeasts. Currently we are working on tying individual microbial species to specific pollinators and expanding this research to native Asclepias species in the area.

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1 - California State University, Dominguez Hills, 1000 E Victoria Street, Carson, CA, 90747, United States
2 - Stanford University, 371 Serra Mall, Stanford, CA, 94305, United States

none specified

Presentation Type: Oral Paper
Session: SYMB1, Symbioses: Plant, Animal, and Microbe Interactions
Location: Tucson J/Starr Pass
Date: Wednesday, July 31st, 2019
Time: 8:15 AM
Number: SYMB1002
Abstract ID:588
Candidate for Awards:None

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