Biology subjects

Jarvis, D.

Publications and source records attributed to Jarvis, D..

3 recordsLinked to original sources

bioRxiv2025

Leaf shape modulates climate trait relationships in the wild species Chenopodium hircinum (Amaranthaceae)

Understanding how leaf morphology mediates plant responses to environmental variation is essential for predicting species adaptability under climate change. In this study, we investigated natural variation in leaf shape and associated functional- physiological traits (FPTs) across populations of Chenopodium hircinum grown in a common garden. We found that leaf shape strongly correlates with the climatic conditions of population provenance, while functional and physiological traits are independently associated with morphology rather than directly with climate. Landmark-based morphometric analysis revealed that the second principal component, distinguishing deeply lobed from rounded leaves, is significantly linked to key traits such as leaf mass per unit area (LMA) and stomatal conductance. These relationships suggest that morphology mediates a functional continuum between resource-use strategies. Notably, within-population phenotypic variation accounted for much of the observed trait diversity, underscoring the role of individual-level phenotypic plasticity in shaping ecological function. Our results challenge traditional views on the thermoregulatory role of leaf lobation and highlight morphology as a central axis of adaptation. This work advances understanding of trait integration in response to environmental heterogeneity and suggests that plasticity in leaf shape and function may enhance resilience of C. hircinum across its native range.

plant biology↗

bioRxiv2024

NeuralPlayground: A Standardised Environment for Evaluating Models of Hippocampus and Entorhinal Cortex

Neural processes in the hippocampus and entorhinal cortex are thought to be crucial for spatial cognition. A growing variety of theoretical models have been proposed to capture the rich neural and behavioral phenomena associated with these circuits. However, systematic comparison of these theories, both against each other and against empirical data, remains challenging. To address this gap, we present NeuralPlayground, an open-source standardised software framework for comparisons between theory and experiment in the domain of spatial cognition. This Python software package offers a reproducible way to compare models against a centralised library of published experimental results, including neural recordings and animal behavior. The framework implements three Agents embodying different computational models; three Experiments comprising publicly available neural and behavioral datasets; a customisable 2-dimensional Arena (continuous and discrete) able to generate common and novel spatial layouts; and a Comparison tool that facilitates systematic comparisons between models and data. Each module can also be used separately, allowing standardised and flexible access to influential models and data sets. We hope NeuralPlayground, available on GitHub3, provides a starting point for a shared, standardized, open, and reproducible computational understanding of the role of the hippocampus and entorhinal cortex in spatial cognition.

neuroscience↗

bioRxiv2021

The oldest peracarid crustacean reveals a Late Devonian freshwater colonisation by isopod relatives

Peracarida (e.g., woodlice & side-swimmers) are, together with their sister-group Eucarida (e.g. krill & decapods), the most speciose group of modern crustaceans, suggested to have appeared as early as the Ordovician. While eucarids incursion onto land consists of mainly freshwater and littoral grounds, some peracarids have evolved fully terrestrial ground-crawling ecologies, inhabiting even our gardens in temperate regions (e.g. pillbugs and sowbugs). Their fossil record extends back to the Carboniferous and consists mainly of marine occurrences. Here, we provide a complete re-analysis of a fossil arthropod - Oxyuropoda - reported in 1908 from the Late Devonian floodplains of Ireland, and left with unresolved systematic affinities despite a century of attempts at identification. Known from a single specimen preserved in two-dimensions, we analysed its anatomy using digital microscopy and multispectral macro-imaging to enhance contrast of morphological structures. The new anatomical characters and completeness of Oxyuropoda, together with a phylogenetic analysis with representatives of all major Eumalacostraca groups, indicate that Oxyuropoda is a crown-peracarid, part of a clade including amphipods and isopods. As such, Oxyuropoda is the oldest known Peracarida, and provides evidence that derived peracarids had an incursion into freshwater and terrestrial environments as early as the Famennian, more than 360 million years ago.

paleontology↗