Preening as a Vehicle for Key Bacteria in Hoopoes

  title={Preening as a Vehicle for Key Bacteria in Hoopoes},
  author={{\'A}ngela Mart{\'i}nez-Garc{\'i}a and Juan Jos{\'e} Soler and Sonia M. Rodr{\'i}guez-Ruano and Manuel Mart{\'i}nez-Bueno and Antonio Manuel Mart{\'i}n-Platero and Natalia Ju{\'a}rez-Garc{\'i}a and Manuel Mart{\'i}n-Vivaldi},
  journal={Microbial Ecology},
Oily secretions produced in the uropygial gland of incubating female hoopoes contain antimicrobial-producing bacteria that prevent feathers from degradation and eggs from pathogenic infection. Using the beak, females collect the uropygial gland secretion and smear it directly on the eggshells and brood patch. Thus, some bacterial strains detected in the secretion should also be present on the eggshell, beak, and brood patch. To characterize these bacterial communities, we used Automatic… 
Seasonal and Sexual Differences in the Microbiota of the Hoopoe Uropygial Secretion
It is hypothesize that bacterial proliferation may be host-regulated in phases of high infection risk (i.e., nesting) and highlighted the importance of specific antimicrobial-producing bacteria present only in dark secretions that may be key in this defensive symbiosis.
The Hoopoe's Uropygial Gland Hosts a Bacterial Community Influenced by the Living Conditions of the Bird
The bacterial assemblage of this community was largely invariable among study individuals, although differences were detected between captive and wild female hoopoes, with some strains showing significantly higher prevalence in wild birds.
Nest Bacterial Environment Affects Microbiome of Hoopoe Eggshells, but Not That of the Uropygial Secretion
First experimental evidence indicating that nest material influences the bacterial community of the eggshells and, therefore, probability of embryo infection is shown, suggesting a role of nest environments of hoopoes as reservoirs of symbiotic bacteria.
Nestedness of hoopoes' bacterial communities: symbionts from the uropygial gland to the eggshell
The results indicate that bacterial communities of eggshells and body parts of female hoopoes are at least partially conditioned by the symbiotic community in the uropygial gland, which is important for understanding this host–microbial mutualism functioning and evolution.
Acquisition of Uropygial Gland Microbiome by Hoopoe Nestlings
The results of this analysis support the idea that the typical composition of the hoopoe gland microbiome is reached by the incorporation of some bacteria during the nestling period, and suggest the existence of a coevolved core microbiome composed by a mix of specialized vertically transmitted strains and facultative symbionts able to coexist with them.
Ectoparasite Activity During Incubation Increases Microbial Growth on Avian Eggs
Evidence is found of a link between eggshell bacterial loads and increased embryo mortality, which provides indirect support for a bacterial-mediated negative effect of ectoparasitism on host offspring.
Effects of Chemical and Auditory Cues of Hoopoes (Upupa epops) in Repellence and Attraction of Blood-Feeding Flies
It is suggested that uropygial secretion of hoopoes, and symbiotic bacteria living in this secretion, may repel blood-feeding flies from their nests.
Properties, Genetics and Innate Immune Function of the Cuticle in Egg-Laying Species
This review provides insight into the physiological and microbiological characteristics of eggshell cuticle in relation to its protective function (innate immunity) in egg-laying birds and reptiles.
Preen oil and bird fitness: a critical review of the evidence
  • G. Moreno-Rueda
  • Biology
    Biological reviews of the Cambridge Philosophical Society
  • 2017
The uropygial gland appears to have several non‐mutually exclusive functions in birds, and thus is likely to be subject to several selective pressures, and future studies should consider how the inevitable trade‐offs among different functions drive the evolution of uropyGial gland secretions.
Reproductive success related to uropygial gland volume varies with abundance of conspecifics in barn swallows Hirundo rustica
It is found that barn swallows with larger uropygial glands had higher breeding success when living in environments with higher abundance of conspecifics, and the outcomes suggest that benefits of uropgial secretion are host density dependent, thus consistent with this being a heritable trait that has evolved as a consequence of divergent selection imposed by pathogens.


Special structures of hoopoe eggshells enhance the adhesion of symbiont-carrying uropygial secretion that increase hatching success.
The findings of specialized crypts on the eggshells of hoopoes, and of video-recorded females smearing secretion containing symbiotic bacteria at a high density onto the eggShells strongly support a link between secretion and bacteria on eggs.
Symbiotic bacteria living in the hoopoe's uropygial gland prevent feather degradation
The results suggest that by preening their feathers hoopoes benefit from their symbiotic relationship with bacteriocin-producing enterococci, which constitute a chemical defence against feather degradation.
Symbiotic association between hoopoes and antibiotic- producing bacteria that live in their uropygial gland
A tight symbiotic interaction between bacteria that produce antibiotic substances and the hoopoes is suggested, as well as the association with the presence of bacteria living inside their uropygial gland.
Antimicrobial chemicals in hoopoe preen secretions are produced by symbiotic bacteria
Support is found for the hypothesized role of bacteria in the production of such antimicrobial chemicals in hoopoe preen secretions because experimental clearance of bacteria from glands of nestlings with antibiotics resulted in secretions without most of the volatiles detected in control individuals.
Hoopoes color their eggs with antimicrobial uropygial secretions
It is found that eggs stayed bluish-gray in nests where female access to the uropygial secretion was experimentally blocked, which strongly support the hypothesis that female hoopoes use their uropgial gland secretion to color the eggs.
Characterization of Antimicrobial Substances Produced by Enterococcus faecalis MRR 10-3, Isolated from the Uropygial Gland of the Hoopoe (Upupa epops)
This is the first time that the production of bacteriocins by a bacterium isolated from the uropygial gland has been described and may be important to the hygiene of the nest and thus to the health of the eggs and chicks.
Environmental Factors Shape the Community of Symbionts in the Hoopoe Uropygial Gland More than Genetic Factors
H hoopoes are able to incorporate new symbionts from the environment during the development of the uropygium, which could be a selective advantage if strains with higher antimicrobial capacity are incorporated into the gland and could aid hosts in fighting against pathogenic and disease-causing microbes.
The evolution of size of the uropygial gland: mutualistic feather mites and uropygial secretion reduce bacterial loads of eggshells and hatching failures of European birds
The size of the uropygial gland was positively related to eggshell bacterial loads, and bird species with higher diversity and abundance of feather mites harboured lower bacterial density on their eggshells (Enterococcus and Staphylococcus), in accordance with the hypothesis.
Bacteriocins with a broader antimicrobial spectrum prevail in enterococcal symbionts isolated from the hoopoe's uropygial gland.
It is suggested that fitness-related benefits for hoopoes associated with harbouring the most bactericidal symbionts cause the highest frequency of strains carrying MR10 and AS-48 genes.
Seasonal, sexual and developmental differences in hoopoe Upupa epops preen gland morphology and secretions: evidence for a role of bacteria
The results suggest that some of the special properties of hoopoe glands are mediated by the presence of symbiotic bacteria.