Biology subjects

Pozas-Schacre, C.

Publications and source records attributed to Pozas-Schacre, C..

2 recordsLinked to original sources

bioRxiv2026

Host genetics structure prokaryotic and Symbiodiniaceae assemblages and their co-variation in sympatric fire coral species

Host-symbiont specificity and environmental filtering are important constraints on holobiont structure and resilience. Yet, resolving the extent of these constraints requires moving beyond species-level resolution, as intraspecific host genetic diversity can further modulate symbiotic associations in ways that remain poorly understood. Here, we resolved host genetic identity at the subspecies level to disentangle drivers of symbiotic plasticity in three sympatric fire coral species (Millepora cf. exaesa, M. tenera, and M. cf. platyphylla) across three adjacent but environmentally distinct habitats on Reunion Island (inner and outer reef flats, reef slope,). Symbiont assemblages were primarily structured by host species and genotypes, with a stronger genetic influence on Symbiodiniaceae than on prokaryotic assemblages, while habitat played a significant but secondary role. Symbiodiniaceae communities were dominated by Symbiodinium A16 and A3 radiations, showing marked specificity across species and habitats. All Millepora species consistently associated with the Spirochaetaceae, Kiloniellaceae and Desulfobacteraceae bacterial families across all habitats, suggesting evolutionarily maintained core associations. Both symbiotic compartments shifted across every habitat in host-specific ways, demonstrating microbiome plasticity to local environmental conditions. Integration of symbiont sequence data (ITS2 and 16S) further revealed genotype-specific co-variation patterns, with some genotypes maintaining stable and co-varying symbionts across clones, while others exhibited greater plasticity. Together, our results indicate that fire coral holobionts acquire symbionts from locally available pools based primarily on their specific genetic compatibility. This study sheds light on how fine-scale host identity and environment jointly shape unique host-symbiont associations contributing to the ecological success of these sympatric coral species.

ecology↗

bioRxiv2020

Global gut content data synthesis and phylogeny delineate reef fish trophic guilds

The diversity of life on our planet has produced a remarkable variety of biological traits that characterize different species. Such traits are widely employed instead of taxonomy to increase our understanding of biodiversity and ecosystem functioning. However, for species trophic niches, one of the most critical aspects of organismal ecology, a paucity of empirical information has led to inconsistent definitions of trophic guilds based on expert opinion. Using coral reef fishes as a model, we show that experts often disagree on the assignment of trophic guilds for the same species. Even when broad categories are assigned, 60% of the evaluated trait schemes disagree on the attribution of trophic categories for at least 20% of the species. This disagreement greatly hampers comparability across studies. Here, we introduce a quantitative, unbiased, and fully reproducible framework to define species trophic guilds based on empirical data. First, we synthesize data from community-wide visual gut content analysis of tropical coral reef fishes, resulting in trophic information from 13,961 individuals belonging to 615 reef fish species across all ocean basins. We then use network analysis to cluster the resulting global bipartite food web into distinct trophic guilds, resulting in eight trophic guilds, and employ a Bayesian phylogenetic model to predict trophic guilds based on phylogeny and maximum body size. Our model achieved a misclassification error of 5%, indicating that our approach results in a quantitative and reproducible trophic categorization scheme, which can be updated as new information becomes available. Although our case study is for reef fishes, the most diverse vertebrate consumer group, our approach can be applied to other organismal groups to advance reproducibility in trait-based ecology. As such, our work provides an empirical and conceptual advancement for trait-based ecology and a viable approach to monitor ecosystem functioning in our changing world.

ecology↗