Biology subjects

McCoy, S. J.

Publications and source records attributed to McCoy, S. J..

4 recordsLinked to original sources

bioRxiv2022

Preferential consumption of benthic cyanobacterial mats by Caribbean parrotfishes

Cyanobacteria are ubiquitous on coral reefs and perform important ecosystem functions. Benthic cyanobacterial mats (BCMs) have become increasingly abundant on degraded reefs. While epilithic and endolithic benthic cyanobacteria are the primary trophic resource for many parrotfishes, mat-forming benthic cyanobacteria are generally considered unpalatable to reef fishes. Regardless, recent studies have documented substantial grazing of BCMs by reef fishes, including parrotfishes. Here, we observed foraging in five Caribbean parrotfishes on the fringing coral reefs of Bonaire, Netherlands, to investigate BCM consumption relative to other benthic substrates. All species overwhelmingly targeted reef substrates composed of algal turfs and crustose coralline algae, which are typically associated with epilithic and endolithic microalgal and cyanobacterial communities. Additionally, three species preferentially consumed BCMs. As such, our work is consistent with and provides direct evidence supporting the recently proposed trophic role for parrotfishes as microphages. Contrasting observations of reef fishes avoiding substrates dominated by BCMs on other reefs suggests variation in the palatability of BCMs to grazing reef fishes, or species-specific differences in preference for these potentially nutritional trophic resources.

ecology↗

bioRxiv2022

Spatial interactions between parrotfishes and implications for species coexistence

Home range behavior mediates species interactions and distributions, and spatiotemporal segregation may facilitate coexistence of competing species. We investigated home range behavior and spatial interactions in four common parrotfishes on coral reefs in Bonaire, Caribbean Netherlands, to determine how spatial interactions mediate species interactions and contribute to their coexistence. We first computed home ranges for males and females of each species. We then quantified spatial overlap (i.e., static interaction) between the home ranges of neighboring male parrotfishes and their activity in shared areas to estimate interaction potential for pairs of individuals. Finally, we analyzed dynamic interactions in simultaneously tracked, spatially co-occurring interspecific pairs of parrotfishes to investigate how they interact in shared space. Generally, spatial overlap of home ranges was much lower for intraspecific pairs than for interspecific pairs, but the probability of finding males in areas shared with males of other species was species-dependent. Males in interspecific pairs moved mostly independently of each other in shared areas, but we did find some evidence of avoidance in interspecific pairs sharing the most space. We discuss our findings within the context of parrotfish social and foraging ecology to further elucidate the spatial ecology of these functionally important reef fishes.

ecology↗

bioRxiv2022

Predation, community asynchrony, and metacommunity stability in cyanobacterial mats

The dynamism of ecological interactions in rapidly changing ecosystems can be understood only by linking community context to population dynamics. Holistic characterization of such mechanisms requires integrating patterns of variability across scales. Here, we integrated observational, experimental, and theoretical approaches to unify local and regional ecological processes driving the dynamics of benthic cyanobacterial mats on coral reefs off the island of Bonaire, Caribbean Netherlands. Community and metacommunity dynamics of mats were tracked for 49 days alongside quantification of macropredation pressure from fishes. We tested the hypothesis that enhanced predation would result in decreased mat persistence in situ. Finally, we constructed a cellular automaton model to predict patterns in mat metacommunity dynamics across different scenarios of top-down and bottom-up control and dispersal. Cyanobacterial mat metacommunities were temporally stable across the study, stabilized by asynchrony in the dynamics of communities. Diverse reef fishes foraged on mats in situ and experimental increases in predation pressure decreased the instantaneous mortality rate of mat communities over mat communities experiencing natural levels of predation pressure. Theoretical simulations suggested that dispersal conveys a rescuing effect on mat metacommunity abundance under scenarios of strong trophic control.

ecology↗

bioRxiv2022

Top-heavy trophic structure within benthic viral dark matter

Viruses exert considerable influence on microbial population dynamics and community structure, with cascading effects on ecosystem-scale biogeochemical cycling and functional trajectories. Creating broadly generalizable theory on viral trophic ecology requires further inquiry into historically unexplored microbial systems that currently lack empirically demonstrated patterns in viral infectivity, such as structurally complex benthic communities. This becomes increasingly relevant considering recently proposed revisions to the fundamental mechanisms that modulate the strength and direction viral trophic linkages. Here, we employed deep longitudinal multiomic sequencing to characterize the viral assemblage (including ssDNA, dsDNA, and dsRNA viruses) and profile lineage-specific host-virus interactions within benthic cyanobacterial mats sampled from Bonaire, Caribbean Netherlands, over a complete diel time-series, and reconstruct patterns in intra-mat trophic structure. We recovered 11,020 unique viral populations spanning at least 10 viral families across the orders Caudovirales, Petitvirales, and Mindivirales, with evidence for extensive genomic novelty from reference and environmental viral sequences. Analysis of coverage ratios of viral sequences and computationally predicted hosts spanning 15 phyla and 21 classes revealed virus:host abundance and activity ratios consistently exceeding 1:1, with overall power-law scaling indicating an increasingly top-heavy intra-mat trophic structure with significant top-down pressure. Diel activity of cyanophages showed clear temporal patterns that seem to follow host physiological condition. These data generate important hypotheses concerning taxon-dependent variation in the relative contribution of top-down vs. bottom-up forcing in driving mat community dynamics, and establish a useful database of viral sequences from this previously unexplored system toward the generation of generalizable trans-system theory on viral trophic ecology. SIGNIFICANCE STATEMENTRecent advances in viral ecological theory suggest a better understanding of system-specific viral ecology is needed from diverse environments to create generalizable theory that accurately predicts patterns of trophic interaction strengths across systems, especially in the Anthropocene. This study characterized viral-host trophic structure within coral reef benthic cyanobacterial mats - a globally proliferating cause and consequence of coral reef degradation - using paired multiomic sequencing. Recovered viral sequences displayed remarkable genomic novelty from other well-characterized viruses and spanned diverse viral taxa. Unexpectedly, lineage-resolved trophic linkages displayed a strongly active top-heavy trophic structure, suggesting extensive top-down forcing. These results highlight the context-dependence of viral trophic interaction strengths and suggest that viruses strongly influence reef cyanobacterial mat and reef ecosystem functional trajectories.

ecology↗