Herbivorous reptiles depend on complex gut microbial communities to effectively degrade dietary polysaccharides. The composition of these fermentative communities may vary based on dietary differences. To explore the role of diet in shaping gut microbial communities, we evaluated the fecal samples from two related host speciesthe algae-consuming marine iguana (Amblyrhynchus cristatus) and land iguanas (LI) (genus Conolophus) that consume terrestrial vegetation. Marine and LI fecal samples were collected from different islands in the Galápagos archipelago. High-throughput 16S rRNA-based pyrosequencing was used to provide a comparative analysis of fecal microbial diversity. At the phylum level, the fecal microbial community in iguanas was predominated by Firmicutes (69.5±7.9%) and Bacteroidetes (6.2±2.8%), as well as unclassified Bacteria (20.6±8.6%), suggesting that a large portion of iguana fecal microbiota is novel and could be involved in currently unknown functions. Host species differed in the abundance of specific bacterial groups. Bacteroides spp., Lachnospiraceae and Clostridiaceae were significantly more abundant in the marine iguanas (MI) (P-value>1E9). In contrast, Ruminococcaceae were present at >5-fold higher abundance in the LI than MI (P-value>6E14). Archaea were only detected in the LI. The number of operational taxonomic units (OTUs) in the LI (356-896 OTUs) was >2-fold higher than in the MI (112-567 OTUs), and this increase in OTU diversity could be related to the complexity of the resident bacterial population and their gene repertoire required to breakdown the recalcitrant polysaccharides prevalent in terrestrial plants. Our findings suggest that dietary differences contribute to gut microbial community differentiation in herbivorous lizards. Most importantly, this study provides a better understanding of the microbial diversity in the iguana gut; therefore facilitating future efforts to discover novel bacterial-associated enzymes that can effectively breakdown a wide variety of complex polysaccharides.
|Original language||English (US)|
|Number of pages||10|
|State||Published - Sep 2011|
Bibliographical noteFunding Information:
We would like to thank M Wikelski for long-term support and concepts, as well as access to infrastructure on the islands (CDRS and GNP) that made the study possible. We thank Augusto G Haz Beltran and Lenin Cruz Beldon for assistance with the field work and sample collection. We also like to thank the Charles Darwin Research Station, Director Washington Tapia and the Galápagos National Parks for professional and logistical assistance in conducting field work and obtaining all the necessary permits for collection and export of fecal samples. PYH was supported in part by funds from USDA-NRI (1-489318-231000-191100). EW was supported by the US Environmental Protection Agency Science to Achieve Results Fellowship program. This publication was developed with partial support from a STAR Research Assistance Agreement No. 91684301-1 awarded by the U.S. Environmental Protection Agency. It has not been formally reviewed by the EPA. The views expressed in this document are solely those of the authors and the EPA does not endorse any products or commercial services mentioned in this publication.
- 16S rRNA-based pyrosequencing
- Galápagos iguanas
- dietary differences
- fecal microbiota
ASJC Scopus subject areas
- Ecology, Evolution, Behavior and Systematics