The crocodile lizard is a critically endangered reptile, and serious diseases have been found in this species in recent years, especially in captive lizards. Whether these diseases are caused by changes in the gut microbiota and the effect of captivity on disease remains to be determined. Here, we examined the relationship between the gut microbiota and diet and disease by comparing the fecal microbiota of wild lizards with those of sick and healthy lizards in captivity. The gut microbiota in wild crocodile lizards was consistently dominated by Proteobacteria (∼56.4%) and Bacteroidetes (∼19.1%). However, the abundance of Firmicutes (∼2.6%) in the intestine of the wild crocodile lizards was distinctly lower than that in other vertebrates. In addition, the wild samples from Guangdong Luokeng Shinisaurus crocodilurus National Nature Reserve also had a high abundance of Deinococcus–Thermus while the wild samples from Guangxi Daguishan Crocodile Lizard National Nature Reserve had a high abundance of Tenericutes. The gut microbial community in loach-fed crocodile lizards was significantly different from the gut microbial community in the earthworm-fed and wild lizards. In addition, significant differences in specific bacteria were detected among groups. Notably, in the gut microbiota, the captive lizards fed earthworms resulted in enrichment of Fusobacterium, and the captive lizards fed loaches had higher abundances of Elizabethkingia, Halomonas, Morganella, and Salmonella, all of which are pathogens or opportunistic pathogens in human or other animals. However, there is no sufficient evidence that the gut microbiota contributes to either disease A or disease B. These results provide a reference for the conservation of endangered crocodile lizards and the first insight into the relationship between disease and the gut microbiota in lizards.

In this paper, the autoaggregating, coaggregating, hydrophobicity, and adhering abilities of 22 Lactobacillus strains belonging to different species were assessed. No correlation existed between autoaggregation and adhesion of the strains belonging to different species, whereas a positive correlation existed between autoaggregation and adhesion of the strains belonging to the same species. After treating with guanidine HCl, the autoaggregating and adhering abilities of some Lactobacillus strains decreased, indicating that surface-bound proteins and other macromolecules played a role in the adhering and autoaggregating abilities. The strains Lactobacillus plantarum 20 and 66 had higher adhesion and coaggregation abilities and should be further studied for their probable probiotic properties. Aggregating, coaggregating, and adhering abilities of Lactobacillus strains could be used as the preliminary criteria for selecting strains having probiotic potential.

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Summary1. Differences in body size between mainland and island populations have been reported for reptiles, birds and mammals. Despite widespread recognition of insular shifts in body size in these taxa, there have been no reports of such body size shifts in amphibians. 2. We provide the first evidence of an insular shift in body size for an amphibian species, the rice frog Rana limnocharis . We found significant increases in body size of rice frogs on most sampled islands in the Zhoushan archipelago when compared with neighbouring mainland China. 3. Large body size in rice frogs on islands was significantly related to increased population density, in both breeding and non-breeding seasons. Increases in rice frog density were significantly related to higher resource availability on islands. Increased resource availability on islands has led to higher carrying capacities, which has subsequently facilitated higher densities and individual growth rates, resulting in larger body size in rice frogs. We also suggest that large body size has evolved on islands, as larger individuals are competitively superior under conditions of harsh intraspecific competition at high densities. 4. Increases in body size in rice frogs were not related to several factors that have been implicated previously in insular shifts in body size in other taxa. We found no significant relationships between body size of rice frogs and prey size, number of larger or smaller frog species, island area or distance of islands from the mainland. 5. Our findings contribute to the formation of a broad, repeatable ecological generality for insular shifts in body size across a range of terrestrial vertebrate taxa, and provide support for recent theoretical work concerning the importance of resource availability for insular shifts in body size.