Biology subjects

Wainwright, P. C.

Publications and source records attributed to Wainwright, P. C..

6 recordsLinked to original sources

bioRxiv2026

Habitat-specific temporal variation in the pace of fish diversification

Speciation and extinction events are concentrated unevenly through space and time, shaping the global distribution of extant biodiversity. Habitats modulate these dynamics over short timescales by determining the ecological landscape and providing substrate for diversification. This raises questions about whether biotic and abiotic heterogeneity across habitats also influenced diversification rate over geological timescales. Here, we show the rate of species diversification varies through time according to major differences between aquatic habitats for ray-finned fishes, which comprise over half of vertebrate diversity. Phylogeny-wide net diversification rates have accelerated 1.5-1.7x in reef-associated, freshwater benthopelagic and freshwater demersal lineages, which inhabit complex benthic habitats, while remaining constant through time in other less complex habitats such as the pelagic zone. Combined evidence across multiple diversification models implicates the rise of benthic-feeding fishes, which capitalized on functional feeding innovations and the reorganization of benthic resources following the Paleocene-Eocene Thermal Maximum. Our results show that the global biodiversity of ray-finned fishes is shaped by a combination of clade-specific pulses and tree-wide rate shifts, an outcome of the dynamic interplay between the traits of species and the features of the habitats they occupy. Significance statementAquatic habitats vary considerably in their biotic and abiotic properties. In this study, we demonstrate that these differences have modulated the pace of species diversification through time for ray-finned fishes, a group that represents over half of extant vertebrate species. By estimating habitat-specific speciation and extinction rates at a high temporal resolution, we find accelerated diversification beginning [~]50 Mya for species living in complex benthic habitats. We show that this pattern is in part driven by the rise of species that took advantage of functional innovations to feed on a diverse array of benthic associated resources, like coral and algae. These results highlight the interplay between the traits of species and the properties of the habitats they occupy in generating the biodiversity patterns observed today.

evolutionary biology↗

bioRxiv2026

Latent feeding behaviors promote trophic versatility in cichlids

The relationship between morphology and ecology is mediated by behavior. We explore this relationship by assessing the link between trophic ecology and the use of prey-specific feeding behaviors in a cichlid fish system. Cichlid diversification features repeated transitions between free-moving prey and attached benthic prey, requiring predators to evolve prey-specific approaches to feeding. Using 2000 Hz video, we characterized feeding behavior on an experimental attached benthic prey in seven species of Mesoamerican heroine cichlid spanning three independent transitions to specialized piscivory and two to specialized benthic-feeding ecology. We investigated the effect of feeding ecology on the behavior and kinematics of benthic grazing, a derived, specialized mode of cichlid feeding. Surprisingly, all species readily fed on benthic prey, regardless of their feeding ecology. Nearly all non-benthic species used the same benthic-feeding behaviors as ecological benthic-feeders. Our findings demonstrate an unexpected level of behavioral versatility among cichlid species in exploiting functionally demanding prey outside their typical diets. We propose that this repertoire of latent feeding behaviors supports trophic versatility and facilitates niche diversification. We also show that two benthic-feeding lineages of Neotropical cichlids evolved distinct approaches to benthic feeding, exhibiting the highest and lowest total feeding-strike kinesis, respectively. Together, our findings highlight the importance of behavior in linking morphology and ecology and motivate further study into the diversity and evolutionary context of benthic feeding across the Cichlidae. SUMMARY STATEMENTWe demonstrate that prey-specific feeding behaviors and strike kinematics vary with trophic ecology in heroine cichlids and discuss the potential role of latent feeding behaviors in trophic diversification.

animal behavior and cognition↗

bioRxiv2023

Replicated Functional Evolution in Cichlid Adaptive Radiations

Adaptive radiations highlight the mechanisms by which species and traits diversify and the extent to which these patterns are predictable. We used 1,110 high-speed videos of suction feeding to study functional and morphological diversification in 300 cichlid species from three African Great Lake radiations of varying ages (Tanganyika, Malawi and Victoria) and an older, spatially dispersed continental radiation in the Neotropics. Among African radiations, standing diversity was reflective of time. Morphological and functional variance in Lake Victoria, the youngest radiation, was a subset of that within Lake Malawi, which itself was nested within the older Tanganyikan radiation. However, functional diversity in Neotropical cichlids was often lower than in Lake Tanganyika, despite being at least 25 My older. These two radiations broadly overlapped, but each diversified into novel trait spaces not found in the youngest lake radiations. Evolutionary rates across radiations were inversely related to age, suggesting, at least for lake radiations, extremely rapid trait evolution at early stages. Despite this support for early bursts, other patterns of trait diversity were inconsistent with expectations of adaptive radiations. This work suggests that cichlid functional evolution has played out in strikingly similar fashion in different radiations, with contingencies eventually resulting in lineage-specific novelties.

evolutionary biology↗

bioRxiv2021

Prolonged morphological expansion of spiny-rayed fishes following the end-Cretaceous

Spiny-rayed fishes (Acanthomorpha) dominate modern marine habitats and comprise more than a quarter of all living vertebrate species1-3. It is believed that this dominance resulted from explosive lineage and phenotypic diversification coincident with the Cretaceous-Paleogene (K-Pg) mass-extinction event4. It remains unclear, however, if living acanthomorph diversity is the result of a punctuated burst or gradual accumulation of diversity following the K-Pg. We assess these hypotheses with a time-calibrated phylogeny inferred using ultraconserved elements from a sampling of species that represent over 91% of all acanthomorph families, as well as an extensive body shape dataset of extant species. Our results indicate that several million years after the end-Cretaceous, acanthomorphs underwent a prolonged and significant expansion of morphological disparity primarily driven by changes in body elongation, and that acanthomorph lineages containing the bulk of the living species diversity originated throughout the Cenozoic. These acanthomorph lineages radiated into distinct regions of morphospace and retained their iconic phenotypes, including a large group of laterally compressed reef fishes, fast-swimming open-ocean predators, bottom-dwelling flatfishes, seahorses, and pufferfishes. The evolutionary success of spiny-rayed fishes is the culmination of a post K-Pg adaptive radiation in which rates of lineage diversification were decoupled from periods of high phenotypic disparity.

evolutionary biology↗

bioRxiv2021

Reevaluating claims of ecological speciation in Halichoeres bivittatus

Understanding the role of ecological processes in speciation has become one of the most active areas of research in marine population biology in recent decades. The traditional view was that allopatry was the primary driver of speciation in marine taxa, but the geography of the marine environment and the dispersal capabilities of many marine organisms render this view somewhat questionable. One of the earliest and most highly cited empirical examples of ecological speciation with gene flow in marine fishes is that of the slippery dick wrasse, Halichoeres bivittatus. Evidence for this cryptic or incipient speciation event was primarily in the form of a deep north-south divergence in a single mitochondrial locus, combined with a finding that these two haplotypes were associated with different habitat types in the Florida Keys and Bermuda, where they overlap. Here we examine habitat assortment in the Florida Keys using a broader sampling of populations and habitat types than were available for the original study, and find no evidence to support the claim that haplotype frequencies differ between habitat types, and little evidence to support any differences between populations. These results severely undermine claims of ecological speciation with gene flow in Halichoeres bivittatus. We argue that future claims of this type should be supported by multiple lines of evidence that illuminate potential mechanisms and allow researchers to rule out alternative explanations for spatial patterns of genetic differences.

evolutionary biology↗

bioRxiv2019

Correlated evolution of sex allocation and mating system in wrasses and parrotfishes

In accordance with predictions of the size-advantage model, comparative evidence confirms that protogynous sex change is lost when mating behavior is characterized by weak size advantage. However, we lack comparative evidence supporting the adaptive significance of sex change. Specifically, it remains unclear whether increasing male size advantage induces transitions to protogynous sex change across species, as it can within species. We show that in wrasses and parrotfishes (Labridae), the evolution of protogynous sex change is correlated with polygynous mating, and that the degree of male size advantage expressed by polygynous species influences transitions between different types of protogynous sex change. Phylogenetic reconstructions reveal strikingly similar patterns of sex allocation and mating system evolution with comparable lability. Despite the plasticity of sex determination mechanisms in labrids, transitions trend towards monandry (all males derived from sex-changed females), with all observed losses of protogyny accounted for by shifts in the timing of sex change to prematuration. Likewise, transitions in mating system trend from the ancestral condition of lek-like polygyny toward greater male size advantage, characteristic of haremic polygyny. The results of our comparative analyses are among the first to confirm the adaptive significance of sex change as described by the size-advantage model.

evolutionary biology↗