Symbiotic microbes may mediate songbird chemical signals
Danielle WhittakerKevin Theis
Photo by Marine Drouilly
Symbiotic hypothesis for chemical communication
Symbiotic microbes in spotted hyena scent pouches are responsible for odors in scent marks
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Structure (Bray-Curtis)
ANOSIM: R = 0.36, P = 0.002
Fig Tree
SouthernComfort
Mara River
Emarti Hill
Bacterial community structure varies with clan membership
(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
Photo by Danielle Whittaker
Volatile compounds in preen oil vary with:
SpeciesSexPopulationRelatednessBreeding
conditionQuality …and could play a
role in mate choice.
Photo by Marine Drouilly
Do avian preen glands harbor odor-producing bacteria?
Do adults transmit these bacteria to their offspring during the nestling phase?
Dark-eyed junco (Junco hyemalis)Mountain Lake Biological Station, VA
Dark-eyed Juncos
Seasonal breedersSocially monogamous~30% extra-pair
fertilization (EPF) rateFemales incubate eggs,
both males and females feed nestlings
Nestlings fledge at day 12
Photo by Marine Drouilly
Photo by Dawn O’Neal
Field Methods
13 nests, 64 juncosSwab 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 Marine Drouilly
Extracted DNA from swabs using MO BIO PowerSoil Kits
Illumina MiSeq platform, targeting the V4 region of bacterial 16S rRNA gene
Processed using mothurEach sample subsampled to
5000 sequencesBacterial sequences clustered
based on 97% nucleotide similarity to define OTUs
Sequencing Methods
Photo by Flickr user Super Bay
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%
Top 20 OTUs in junco preen glands:Burkholderiaceae, BurkholderiaBurkholderiaceae, RalstoniaClostridiaceae, ClostridiumClostridiales Family XI, Incertae
Sedis XI, AnaerococcusComamonadaceae, unknownEnterobacteriaceae, unknownEnterobacteriaceae, unknownEnterococcaceae,
EnterococcusHalomonadaceae, KushneriaHalomonadaceae, Salinicola
Kineosporiaceae, KineococcusMicrococcaceae, unknownMoraxellaceae, AlkanindigesMoraxellaceae, unknownMoraxellaceae, unknownUnknown, unknownPseudomonadaceae,
PseudomonasRhodobacteraceae, unknownSphingomonadaceae,
SphingomonasSphingomonadaceae,
Sphingomonas
Other prominent OTUs associated with odor:
Corynebacterium: human axillary odorPorphyromonas: 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
all individuals, NPMANOVA, F = 3.751, P = 0.0001
nestlings only, NPMANOVA, F = 6.946, P = 0.0001
Nestlings were more similar to mother than father
Wilcoxon’s test, N = 34, W = 564, P < 0.0001
Junco preen gland bacterial communities
Highly diverseCluster by nestNestlings closely
resemble each other and mother
Reliable transmission across generations via physical contact
Acknowledgments
Photo by Nicole Gerlach
Tracy TealArvind VenkataramanEllen KettersonSamuel Slowinski