Biology subjects

Benvenuto, C.

Publications and source records attributed to Benvenuto, C..

7 recordsLinked to original sources

bioRxiv2026

Primordial endocrine cells uncouple sexual differentiation from sex-chromosomes

Sexuality among the animal kingdom is remarkably plastic, spanning from gonochorism to sequential or simultaneous hermaphroditism. Over 70 years ago, Charniaux-Cotton hypothesized that sexual plasticity in crustaceans is mediated by primordial cells present in both sexes, which differentiate into an androgenic gland (AG) only in males. Although AG engraftments can masculinize genetic females, it remained unclear whether this reflects long-term integration of donor cells within the host or activation of host primordial AG progenitors. Using the freshwater prawn as an exceptional case of sexual plasticity, where AG-cell transfer yields functional neo-males bearing only female sex-chromosomes, we show, through cellular-resolution approaches, that the AG arises from primordial cells present in every individual, indicating autosomal machinery of sexual differentiation completely independent from the sex-chromosomes.

developmental biology↗

bioRxiv2025

Multi-seasonal eDNA metabarcoding highlights a resurgence in fish diversity across a severely impacted estuarine ecosystem

Aquatic ecosystems have been in an alarming state of decline for decades. Therefore, there is an urgent need for more accessible and rapid monitoring methods that will ultimately allow for restoration programmes to be implemented. In this study, we deployed environmental DNA (eDNA) metabarcoding as a fish monitoring tool in the Mersey estuarine system (UK), where ecosystem productivity has been severely impacted by water quality degradation since the Industrial Revolution. Monthly water samples were collected over a year (2023-2024) throughout the estuary, covering saline, brackish and freshwater zones. Overall, 69 species of fish were detected, increasing the number of known species within the estuary in comparison to both historical and contemporary records (46 and 39, respectively), with a generally higher observed richness within the upper estuary sampled zones where the water chemistry is predominantly freshwater. Notably, we identified several species returning to the system for the first time since pre-industrial times. Peak species richness was recorded during the winter season (December-February). Species compositions varied significantly by month and spatially by zone within months, but not when grouped seasonally. Furthermore, around [~]15% of the species detected were diadromous, with the endangered Atlantic salmon Salmo salar, for example, being frequently detected during its key migratory period. This study highlights the resurgence in fish diversity in a once biologically depleted estuarine ecosystem and demonstrates how eDNA metabarcoding can be implemented for detecting historically absent species, thereby enhancing restoration monitoring efforts globally.

ecology↗

bioRxiv2024

Performance of eDNA capture methods for monitoring fish biodiversity in a hyper-tidal estuary

Environmental DNA (eDNA) has become an established and efficient method for monitoring biodiversity in aquatic systems. However, there is a need to compare and standardise sampling methods across ecosystem types, particularly complex ecosystems such as estuaries where unique challenges for monitoring fish populations are present due to fluctuating environmental factors. Here, we compare fish biodiversity metrics obtained from eDNA metabarcoding data using four different eDNA filtering methods: three manual filtering methods with different pore sizes (0.45, 1.2 and 5 {micro}m) and a newly established passive method, the metaprobe. The study was applied across a salinity gradient in a hyper-tidal estuarine ecosystem. Overall, 44 fish species were detected across the four methods used. The 0.45 {micro}m filter recovered the highest richness (39 species), then the metaprobe method (35), followed by the 1.2 {micro}m (34) and 5 {micro}m (33) filters. Filter performance between salinity gradients revealed that the 0.45 {micro}m and the 1.2 {micro}m methods recovered the highest species richness across all sampled zones. The 0.45 {micro}m also had the most consistent detection probabilities using representative species from each zone. While the 0.45 {micro}m method appeared to be the optimal method, each of the methods can be considered as a viable and comparable option for biomonitoring in dynamic ecosystems such as estuaries and rivers. In particular, the passive metaprobe (used in a freshwater system for the first time here) performed well in comparison to the manual filtering methods despite a short deployment time. This study provides critical insights for optimising fish biodiversity assessments using eDNA metabarcoding in estuarine ecosystems, providing a valuable framework for future monitoring efforts in similar systems worldwide.

molecular biology↗

bioRxiv2021

Switches, stability and reversals: the evolutionary history of sexual systems in fish

Sexual systems are highly diverse and have profound consequences for population dynamics and resilience. Yet, little is known about how they evolved. Using phylogenetic Bayesian modelling and a sample of 4614 species, we show that gonochorism is the likely ancestral condition in teleost fish. While all hermaphroditic forms revert quickly to gonochorism, protogyny and simultaneous hermaphroditism are evolutionarily more stable than protandry. In line with theoretical expectations, simultaneous hermaphroditism does not evolve directly from gonochorism but can evolve slowly from sequential hermaphroditism, particularly protandry. We find support for the predictions from life history theory that protogynous, but not protandrous, species live longer than gonochoristic species and invest the least in male gonad mass. The distribution of teleosts sexual systems on the tree of life does not seem to reflect just adaptive predictions, suggesting that adaptations alone may not fully explain why some sexual forms evolve in some taxa but not others (Williams paradox). We propose that future studies should incorporate mating systems, spawning behaviours, and the diversity of sex determining mechanisms. Some of the latter might constrain the evolution of hermaphroditism, while the non-duality of the embryological origin of teleost gonads might explain why protogyny predominates over protandry in teleosts.

evolutionary biology↗

bioRxiv2021

eDNA in a bottleneck: obstacles to fish metabarcoding studies in megadiverse freshwater systems

The current capacity of environmental DNA (eDNA) to provide accurate insights into the biodiversity of megadiverse regions (e.g., the Neotropics) requires further evaluation to ensure its reliability for long-term monitoring. In this study, we first evaluated the taxonomic resolution capabilities of a short fragment from the 12S rRNA gene widely used in fish eDNA metabarcoding studies, and then compared eDNA metabarcoding data from water samples with traditional sampling using nets. For the taxonomic discriminatory power analysis, we used a specifically curated reference dataset consisting of 373 sequences from 264 neotropical fish species (including 47 newly generated sequences) to perform a genetic distance-based analysis of the amplicons targeted by the MiFish primer set. We obtained an optimum delimitation threshold value of 0.5% due to lowest cumulative errors. The barcoding gap analysis revealed only a 50.38% success rate in species recovery (133/264), highlighting a poor taxonomic resolution from the targeted amplicon. To evaluate the empirical performance of this amplicon for biomonitoring, we assessed fish biodiversity using eDNA metabarcoding from water samples collected from the Amazon (Adolpho Ducke Forest Reserve and two additional locations outside the Reserve). From a total of 84 identified Molecular Operational Taxonomic Units (MOTUs), only four could be assigned to species level using a fixed threshold. Measures of -diversity analyses within the Reserve showed similar patterns in each site between the number of MOTUs (eDNA dataset) and species (netting data) found. However, {beta}-diversity revealed contrasting patterns between the methods. We therefore suggest that a new approach is needed, underpinned by sound taxonomic knowledge, and a more thorough evaluation of better molecular identification procedures such as multi-marker metabarcoding approaches and tailor-made (i.e., order-specific) taxonomic delimitation thresholds.

ecology↗

bioRxiv2019

Assessing the potential of environmental DNA metabarcoding for monitoring Neotropical mammals: a case study in the Amazon and Atlantic Forest, Brazil

The application of environmental DNA (eDNA) metabarcoding as a biomonitoring tool has greatly increased in the last decade. However, most studies have focused on aquatic macro-organisms in temperate areas (e.g., fishes). We apply eDNA metabarcoding to detect the mammalian community in two high-biodiversity regions of Brazil, the Amazon and Atlantic Forest. We identified critically endangered and endangered mammalian species in the Atlantic Forest and Amazon respectively and found congruence with species identified via camera trapping in the Atlantic Forest. In light of our results, we highlight the potential and challenges of eDNA monitoring for mammals in these high biodiverse areas.

ecology↗

bioRxiv2018

Environmental DNA metabarcoding as an effective and rapid tool for fish monitoring in canals

Environmental DNA (eDNA) metabarcoding has revolutionized biomonitoring of aquatic habitats. Man-made canal systems are among the least-studied environments in terms of biodiversity in Britain. Here we focus on a case study along an English canal comparing eDNA metabarcoding with two types of electrofishing techniques (wade-and-reach and boom-boat). In addition to corroborating data obtained by electrofishing, eDNA provided a wider snapshot of fish assemblages. Given the semi-lotic nature of canals, we encourage the use of eDNA as a fast and cost-effective tool to detect and monitor whole fish communities.

ecology↗