Biology subjects

Dell, A. I.

Publications and source records attributed to Dell, A. I..

7 recordsLinked to original sources

bioRxiv2026

Mice use predictive environmental cues to adapt predatory behavior in hunting tasks of variable difficulty

Prey capture has long served as a model of complex, multimodal behavior with ethological relevance. In this context, the ability of laboratory animals to capture fleeing prey has been investigated in terms of the sensory systems and neuroanatomical regions required for successful capture. While the ability to hunt is experience-dependent, prey capture is often assumed to be a reflexive behavior, governed by innate neural circuits and a basic drive to obtain food. Whether hunting performance depends on complex learning and cognitive strategy remains largely untested, in part because it is difficult to systematically manipulate the difficulty of predator-prey interactions. To address this, we varied ambient temperature across thousands of trials in which laboratory mice pursued cold-blooded cockroaches, whose movement speed was directly determined by body temperature. As expected, capture difficulty increased as a function of temperature. To test whether mice rely on external cues to adjust their predatory behavior, we then mismatched the ambient temperature and that of the prey, finding that mice learn to use relevant environmental information to inform their hunting strategy. Our results suggest that animals can extract and apply meaningful information from predictive environmental cues to adapt their learned behavior.

animal behavior and cognition↗

bioRxiv2024

Temperature-dependent predation predicts a more reptilian future

Vertebrate diversity increases toward the tropics, but the extent to which this pattern varies with thermoregulatory strategy is unknown. A strong divergence, if confirmed, would imply a global restructuring of vertebrate communities with temperature. Here we present evidence for a novel latitudinal and thermal gradient of comparative vertebrate diversity. Synthesizing over 34,000 terrestrial species distributions, we observe a two-orders-of-magnitude shift in comparative richness with temperature, from endothermic dominance in temperate habitats and high elevations, toward parity with ectotherms in the lowland tropics. Next, we provide experimental support for an underlying thermal gradient of predation. Using machine vision tracking in over 4,500 endotherm-ectotherm predation trials, we show that thermally-mediated differences in performance favor endotherm predators in colder conditions and yield theoretically predicted outcomes, including strike count, distance traveled, and time to capture ectotherm prey. Finally, we integrate theory and data to forecast future patterns of diversity, revealing that as the world gets warmer, it will become increasingly reptilian.

ecology↗

bioRxiv2023

No model to rule them all: a systematic comparison of 83 thermal performance curve models across traits and taxonomic groups

In ectotherms, the performance of physiological, ecological and life-history traits universally increases with temperature to a maximum before decreasing again. Identifying the most appropriate thermal performance model for a specific trait type has broad applications, from metabolic modelling at the cellular level to forecasting the effects of climate change on population, ecosystem and disease transmission dynamics. To date, numerous mathematical models have been designed, but a thorough comparison among them is lacking. In particular, we do not know if certain models consistently outperform others and how factors such as sampling resolution and trait or organismal identity influence model performance. To fill this knowledge gap, we compile 2,739 thermal performance datasets from diverse traits and taxa, to which we fit a comprehensive set of 83 existing mathematical models. We detect remarkable variation in model performance that is not primarily driven by sampling resolution, trait type, or taxonomic information. Our results reveal a surprising lack of well-defined scenarios in which certain models are more appropriate than others. To aid researchers in selecting the appropriate set of models for any given dataset or research objective, we derive a classification of the 83 models based on the average similarity of their fits.

ecology↗

bioRxiv2020

Life history scaling and the division of energy in forests

The competition for light has long been regarded as a key axis of niche partitioning that promotes forest diversity, but available evidence is contradictory. Despite strong tradeoffs between growth and survival with light, field tests suggest neutral forces govern tree composition across forest gaps and resource use across size classes. Here we integrate scaling and niche theory, and use data from >114,000 woody plants in a tropical, old growth forest to test and predict patterns of niche partitioning with size and light. Consistent with predictions, the relative abundance, production, light capture, and richness of species in life histories with fast growth follow a power law relationship, increasing 1-2 orders of magnitude along a solar and size gradient. Competitive neutrality between size classes emerges above the sapling layer, where increasing access to light is counterbalanced by stronger self-shading. Convergent power law patterns of resource partitioning across taxa and spatial scale suggest general life history tradeoffs drive the organization of diverse communities.

ecology↗

bioRxiv2020

Habitat patchiness drives spatial structure in morphological trait variation and co-variation in spotted salamanders (Ambystoma maculatum)

The influence of intraspecific trait variation on species interactions makes trait-based approaches critical to understanding eco-evolutionary processes. Because species occupy habitats that are patchily distributed in space, advancement in trait-based ecology hinges on understanding how trait variation is distributed within and between habitat patches. We sampled larval spotted salamanders (Ambystoma maculatum) across spatially discrete ponds to quantify within- and between-pond variation in mass, length, and their allometric relationship. Between-pond variation explained 7-35% of total observed variation in the length and shape of salamander larvae, depending on the body segment measured (i.e., head, body, or tail). Salamander tail morphology was more variable and exhibited more between-pond variation than head or body morphology. Salamander mass was highly variable and strongly correlated with total length. Allometric analysis revealed that the slopes of mass-length relationships were similar across ponds, but that intercepts differed across ponds. Preliminary evidence hinted that newly constructed ponds were a driver of the observed differences in mass-length relationships. Pond construction may therefore bolster trait diversity across the broader landscape, and in so doing instil more adaptive potential of salamander populations under current and future environmental change.

ecology↗

bioRxiv2017

Towards a Global Framework for Estimating Acclimation and Thermal Breadth that Predicts Risk from Climate Change

Thermal breadth, the range of body temperatures over which organisms perform well, and thermal acclimation, the ability to alter optimal performance temperature and critical thermal maximum or minimum with changing temperatures, reflect the capacity of organisms to respond to temperature variability and are thus crucial traits for coping with climate change. Although there are theoretical frameworks for predicting thermal breadths and acclimation, the predictions of these models have not been tested across taxa, latitudes, body sizes, traits, habitats, and methodological factors. Here, we address this knowledge gap using simulation modeling and empirical analyses of >2,000 acclimation strengths from >500 species using four datasets of ectotherms. After accounting for important statistical interactions, covariates, and experimental artifacts, we reveal that i) acclimation rate scales positively with body size contributing to a negative association between body size and thermal breadth across species and ii) acclimation capacity increases with body size, seasonality, and latitude (to mid-latitudinal regions) and is regularly underestimated for most organisms. Contrary to suggestions that plasticity theory and empirical work on thermal acclimation are incongruent, these findings are consistent with theory on phenotypic plasticity. We further validated our framework by demonstrating that it could predict global extinction risk to amphibian biodiversity from climate change.

ecology↗

bioRxiv2017

Using remote camera traps to assess mammal and bird assemblages across a complex environmental landscape

Animals must navigate a complex mosaic of habitat types, both natural and artificial. As artificial habitats (e.g., agricultural fields) become increasingly abundant in many landscapes, species will be affected differently, depending on their habitat preferences. We investigated the diversity, richness, abundance, and biomass of mammals and birds with remote camera traps that optimized the capture of both large and small animals. Camera traps allowed us to capture natural rates of mammals and birds, which is difficult to obtain using human observers who can affect the behavior of animals and are limited in their spatio-temporal scope and ability to assess nocturnal communities. Our camera trap arrays were established along two transects in a local conservation reserve; one transect ran from an agricultural field to an upland forest and another from a wetland to an upland forest. Over the 6-week study our cameras recorded 2,245 images, within which we observed 483 individuals comprising 16 species of mammals and birds. Our data showed that species composition and abundances were only marginally different between the two transects, with species common to both transects not exhibiting any statistical difference in abundances. Coyotes and armadillos were unique to the riparian transect, and many more bird species were present along the riparian transect than the agricultural transect. Diversity, richness, and total community biomass did not differ significantly between the two transects nor along each transect but there were non-significant trends in predicted directions. Our results revealed that fewer species use the forest immediately adjacent to the agricultural field, but more species use the wetland and the forest immediately adjacent to the wetland. Our results corroborate other studies revealing that certain species are more common in forested areas but also that some species thought to prefer forested areas may actually be more habitat generalists than previously thought.

ecology↗