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Abstract Long-term studies of animal microbiomes under natural conditions are valuable for understanding the effects of host demographics and environmental factors on host-associated microbial communities, and how those effects interact and shift over time. We examined how the cloacal microbiome of wild Sceloporus virgatus (the striped plateau lizard) varies under natural conditions in a multi-year study. Cloacal swabs were collected from wild-caught lizards across their entire active season and over three years in southeastern Arizona, USA. Analyses of 16S rRNA data generated on the Illumina platform revealed that cloacal microbiomes of S. virgatus vary as a function of season, sex, body size, and reproductive state, and do so independently of one another. Briefly, microbial diversity was lowest in both sexes during the reproductive season, was higher in females than in males, and was lowest in females when they were vitellogenic, and microbiome composition varied across seasons, sexes, and sizes. The pattern of decreased diversity during reproductive periods with increased sociality is surprising, as studies in other systems often suggest that microbial diversity generally increases with sociality. The cloacal microbiome was not affected significantly by hibernation and was relatively stable from year to year. This study highlights the importance of long term, wide-scale microbiome studies for capturing accurate perspectives on microbiome diversity and composition in animals. It also serves as a warning for comparisons of microbiomes across species, as each may be under a different suite of selective pressures or exhibit short-term variation from external or innate factors, which may differ in a species-specific manner.
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This content will become publicly available on July 12, 2026
Cloacal microbial diversity is associated with competitive phenotypes in socially polyandrous jacanas
The composition of host-associated microbial communities may correlate with the overall status of the host, including physiology and fitness. New bi-directional hypotheses suggest that sexual behaviors can shape, and be shaped by reproductive microbiomes, which may be particularly important for species with mating systems that feature strong sexual selection. These dynamics have been particularly understudied in female animals. Using 16S rRNA sequencing, we compared the cloacal microbiome of females and males from two socially polyandrous bird species that vary in the strength of sexual selection, Jacana spinosa (Northern Jacana) and J. jacana (Wattled Jacana). We hypothesized that the strength of sexual selection would shape cloacal microbial diversity, such that the more polyandrous J. spinosa would have a more diverse microbiome, and that microbiomes would be more diverse in females than in males. If the reproductive microbiome is indicative of competitive status, we also hypothesized that cloacal microbial diversity would be associated with competitive traits, including plasma testosterone levels, body mass, or weaponry. We found no differences in microbial alpha diversity between species or sexes, but we did find that microbial beta diversity significantly differed between species. We also found a positive relationship between microbial alpha diversity and testosterone in female J. spinosa. Future experiments are needed to explore the potential drivers of correlations between the cloacal microbiome and competitive phenotypes in socially polyandrous jacanas.
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- Award ID(s):
- 2316364
- PAR ID:
- 10628348
- Publisher / Repository:
- Oxford Academic
- Date Published:
- Journal Name:
- Ornithology
- ISSN:
- 0004-8038
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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