Dietary and Sexual Correlates of Gut Microbiota in the Japanese Gecko, Gekko japonicus (Schlegel, 1836)

Abstract

Numerous studies have demonstrated that multiple intrinsic and extrinsic factors shape the structure and composition of gut microbiota in a host. The disorder of the gut microbiota may trigger various host diseases. Here, we collected fecal samples from wild-caught Japanese geckos (Gekko japonicus) and captive conspecifics fed with mealworms (mealworm-fed geckos) and fruit flies (fly-fed geckos), aiming to examine the dietary and sexual correlates of the gut microbiota. We used 16S rRNA gene sequencing technology to determine the composition of the gut microbiota. The dominant phyla with a mean relative abundance higher than 10% were Verrucomicrobiota, Bacteroidota, and Firmicutes. Gut microbial community richness and diversity were higher in mealworm-fed geckos than in wild geckos. Neither community evenness nor beta diversity of gut microbiota differed among wild, mealworm-fed, and fly-fed geckos. The beta rather than alpha diversity of gut microbiota was sex dependent. Based on the relative abundance of gut bacteria and their gene functions, we concluded that gut microbiota contributed more significantly to the host’s metabolic and immune functions. A higher diversity of gut microbiota in mealworm-fed geckos could result from higher chitin content in insects of the order Coleoptera. This study not only provides basic information about the gut microbiota of G. japonicus but also shows that gut microbiota correlates with dietary habits and sex in the species.

Insights into the Gut Microbiome of the South American Leaf-Toed Gecko (Phylodactylus gerropygus) Inhabiting the Core of the Atacama Desert

“…Our study showed that the phyla Bacteroidota, Firmicutes, and Proteobacteria accounted for more than 97% of the gut microbiome, indicating that these bacterial phyla were the predominant ones in P. gerrhopygus . In contrast to our results, the top four dominant bacterial phyla in the Japanese gecko ( Gekko japonicus ) and leopard gecko ( Eublepharis macularius ) were Verrucomicrobiota, Bacteroidota, Firmicutes, and Proteobacteria [ 11 , 57 ]. It was recently reported that Proteobacteria, Firmicutes, Bacteroidota, and Actinobacteria were the dominant phyla of the gut microbiome of the Tokay gecko ( Gekko gecko ) [ 62 ].…”

“…For instance, Arizza et al (2019) found that the dominant bacterial families in the gut microbiome of sea turtles ( Caretta caretta ) included Ruminococcaceae, Rikenellaceae, Lachnospiraceae, and Clostridiales [ 66 ]. However, our results differed from those reported for other geckos, such as the wild-caught Japanese gecko ( G. japonicas ), where the dominant bacterial families were Akkermansiaceae, Bacteroidaceae, Tannerellaceae, Enterobacteriaceae, Lachnospiraceae, and Clostridiaceae [ 57 ]. These discrepancies are likely due to differences in the species, the environmental conditions, and the sampling methods.…”

“…Additionally, members of Bacteroidota display intricate mechanisms for acquiring and breaking down dietary polysaccharides that are otherwise difficult to digest, such as chitin [ 56 ]. Chitin, one of the most abundant biopolymers in nature, is present in the diets of many vertebrates [ 57 ], including P. gerropygus . Prey items typically consumed by the South American leaf-toed gecko in the Atacama Desert primarily consist of arthropods, particularly Coleoptera and insect larvae [ 39 ], which are rich sources of chitin.…”

“…Prey items typically consumed by the South American leaf-toed gecko in the Atacama Desert primarily consist of arthropods, particularly Coleoptera and insect larvae [ 39 ], which are rich sources of chitin. Chitin can potentially restore the microbial community’s compositional balance, showing promising anti-viral, anti-tumor, antifungal, and antimicrobial effects [ 57 , 58 ]. Thus, the enzymatic and regulatory activities of Bacteroidota may contribute to reptile adaptation to digesting more chitin-rich prey items [ 58 , 59 ] in a sex-dependent way.…”