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Symbiotic microbes may mediate songbird chemical signals. Danielle Whittaker Kevin Theis. Photo by Marine Drouilly. Symbiotic hypothesis for chemical communication. Symbiotic microbes in spotted hyena scent pouches are responsible for odors in scent marks. Structure (Bray-Curtis).
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Symbiotic microbes may mediate songbird chemical signals Danielle Whittaker Kevin Theis Photo by Marine Drouilly
Symbiotic microbes in spotted hyena scent pouches are responsible for odors in scent marks Structure (Bray-Curtis) Fig Tree Mara River Southern Comfort Emarti Hill Bacterial community structure varies with clan membership ANOSIM: R = 0.36, P = 0.002 (Theis et al. 2012)
Preen oil is an odor source in birds • Oil secreted from the uropygial gland contains volatile compounds that give birds an odor
Volatile compounds in preen oil vary with: Species Sex Population Relatedness • Breeding condition • Quality …and could play a role in mate choice. Photo by Danielle Whittaker
Do avian preen glands harbor odor-producing bacteria? Do adults transmit these bacteria to their offspring during the nestling phase? Photo by Marine Drouilly
Dark-eyed junco (Junco hyemalis)Mountain Lake Biological Station, VA
Dark-eyed Juncos • Seasonal breeders • Socially monogamous • ~30% extra-pair fertilization (EPF) rate • Females incubate eggs, both males and females feed nestlings • Nestlings fledge at day 12 Photo by Marine Drouilly
Field Methods 13 nests, 64 juncos Swab samples from preen glands: • all nestlings (2-4, mean = 2.9) at age 11-12 days • both parents at all but 2 nests Photo by Dawn O’Neal
SequencingMethods Extracted DNA from swabs using MO BIO PowerSoil Kits IlluminaMiSeq platform, targeting the V4 region of bacterial 16S rRNA gene Processed using mothur Each sample subsampled to 5000 sequences Bacterial sequences clustered based on 97% nucleotide similarity to define OTUs Photo by Marine Drouilly
Bacterial communities in junco preen glands have very high levels of diversity • Top 20 OTUs account for ~45% of sequences, with no OTU accounting for more than 5% In hyena scent glands, the top 20 OTUs account for ~90% of sequences, with the top OTU accounting for ~45% Photo by Flickr user Super Bay
Top 20 OTUs in junco preen glands: • Burkholderiaceae, Burkholderia • Burkholderiaceae, Ralstonia • Clostridiaceae, Clostridium • Clostridiales Family XI, IncertaeSedis XI, Anaerococcus • Comamonadaceae, unknown • Enterobacteriaceae, unknown • Enterobacteriaceae, unknown • Enterococcaceae, Enterococcus • Halomonadaceae, Kushneria • Halomonadaceae, Salinicola • Kineosporiaceae, Kineococcus • Micrococcaceae, unknown • Moraxellaceae, Alkanindiges • Moraxellaceae, unknown • Moraxellaceae, unknown • Unknown, unknown • Pseudomonadaceae, Pseudomonas • Rhodobacteraceae, unknown • Sphingomonadaceae, Sphingomonas • Sphingomonadaceae, Sphingomonas
Other prominent OTUs associated with odor: • Corynebacterium: human axillary odor • Porphyromonas: malodorous breath • Bacteroides, Finegoldia& Fusobacterium: common volatile fatty acid producers associated with many vertebrates
Bacterial community structure varied by nest Nests significantly different (70/78 pairwise comparisons) NPMANOVA, all: F = 3.751, P = 0.0001 (Bray-Curtis) Nestlings only: F = 6.946, P = 0.0001 Photo by Nicole Gerlach
Nestlings were more similar to mother than father Wilcoxon’s test, N = 34, W = 564, P < 0.0001
Junco preen gland bacterial communities • Highly diverse • Cluster by nest • Nestlings closely resemble each other and mother • Reliable transmission across generations via physical contact
Acknowledgments • Tracy Teal • ArvindVenkataraman • Ellen Ketterson • Samuel Slowinski Photo by Nicole Gerlach