Banning JL, Weddle AL, Wahl GW, Simon MA, Lauer A, Walters RL et al.. Antifungal skin bacteria, embryonic survival, and communal nesting in four-toed salamanders, Hemidactylium scutatum. Oecologia 156: 423-429

California State University Bakersfield Department of Biology 9001 Stockdale Highway Bakersfield CA 93311-1099 USA
Oecologia (Impact Factor: 3.09). 05/2008; 156(2):423-429. DOI: 10.1007/s00442-008-1002-5


We examined a novel hypothesis for the maintenance of communal nesting in the salamander, Hemidactylium scutatum, namely that communal nests are more likely than solitary nests to be associated with cutaneous antifungal bacteria, which
can inhibit fungal infections of embryos. A communal nest contains eggs of two or more females of the same species. The nesting
behavior of H. scutatum females and survival of embryos were determined by frequent nest surveys at three ponds. For communal nests, embryonic survival
tended to be higher and catastrophic nest failure was lower. Pure bacterial cultures of resident species were obtained from
the salamanders’ skins by swabbing and tested against a fungal pathogen of embryos (Mariannaea sp.) in laboratory assays. We found that 27% of females had skin bacteria inhibitory to Mariannaea sp. Communal nests were more likely to have at least one female with antifungal bacteria than were solitary nests. Using
a culture-independent assay (denaturing gradient gel electrophoresis of 16S rRNA gene fragments), we found that bacterial
species on females and embryos were more similar to each other than they were to bacterial species found in soil within the
nest, suggesting that females transmitted skin bacteria to embryos. The presence of anti-Mariannaea skin bacteria identified from the laboratory assays did not prevent fungal presence in field nests. However, once a nest
was visibly infected with fungi, presence of anti-Mariannaea bacteria was positively correlated with survival of embryos. Microbe transmission is usually thought to be a cost of group
living, but communal nesting in H. scutatum may facilitate the transmission of antifungal bacteria to embryos.

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    • "The potential for using symbiotic bacteria for probiotic treatments against chytridiomycosis is currently being investigated (reviewed by Bletz et al., 2013), and on-going research has identified symbiotic bacteria that inhibit the growth of the chytridiomycosis fungus, Batrachochytrium dendrobatidis, from a number of amphibian species (e.g. Harris et al., 2006; Culp et al., 2007; Lauer et al., 2007; Banning et al., 2008; Brucker et al., 2008; Flechas et al., 2012; Loudon et al., 2013; Roth et al., 2013). "
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    • "†These authors contributed equally to this work. embryos of shrimp, lobsters, squid, wasps and some salamanders from pathogenic bacteria and/or competitor fungi (Gil-Turnes, Hay & Fenical 1989; Barbieri et al. 1997, 2001; Currie et al. 1999; Kaltenpoth et al. 2005; Cardoza, Klepzig & Raffa 2006; Banning et al. 2008; Scott et al. 2008), or aphid hosts from their parasitoids (Oliver et al. 2003), which illustrate the great variety of animals that use antibiotic-producing bacteria as defence against pathogenic infection. Animals live in a bacterial world, and exploring their physiological, morphological and behavioural characteristics facilitating colonization of beneficial microbes is of prime importance for understanding animal–bacteria interactions in general and the evolution of the mutualistic relationship in particular (McFall-Ngai et al. 2013). "
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