Biology subjects

Trimmer, P. C.

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

4 recordsLinked to original sources

bioRxiv2025

Generalizing Drift Diffusion Models with a State-Dependent Framework

Decision-making in natural environments often involves a trade-off between speed and accuracy, particularly in high-stakes scenarios like predator-prey interactions. Drift Diffusion Models (DDMs) have been used extensively to study speed-accuracy trade-offs, but such work has typically assumed that decisions are made independently of one another. In the wild, the consequences of one decision will often influence future choices. To address this gap, we introduce a new framework - State-Dependent Drift Diffusion Models (S3DMs) - which integrate state-dependent variables into the decision-making process. Using simulations of foraging scenarios, we demonstrate that S3DMs can predict markedly different behavioural outcomes compared to a standard DDM. By incorporating sequential and interdependent decisions, S3DMs offer a framework that is arguably both more realistic and more biologically relevant. Our research contributes to integrating functional and mechanistic explanations of behaviour and suggests a promising direction for future studies in behavioural ecology and neuroscience.

animal behavior and cognition↗

bioRxiv2022

Evolutionary history mediates population response to rapid environmental change through within-generational and transgenerational plasticity

Rapid environmental change is affecting many organisms; some are coping well but many species are in decline. A key mechanism for facilitating success following environmental change is phenotypic plasticity. Organisms use cues to respond phenotypically to environmental conditions; many incorporate recent information (within-generation plasticity) and information from previous generations (transgenerational plasticity). We extend an existing evolutionary model where organisms utilize within-generational plasticity, transgenerational plasticity, rapid evolution, and bet-hedging. We show how, when rapid evolution of plasticity is not possible, the effect of environmental change (altering the environment mean, variance, or autocorrelation, or cue reliability) on population growth rate depends on selection for within-generation plasticity and transgenerational plasticity under historical environmental conditions. We then evaluate the predictions that populations adapted to highly variable environments, or with greater within-generational plasticity, are more likely to successfully respond to environmental change. We identify when these predictions fail, and show environmental change is most detrimental when previously reliable cues become unreliable. When multiple cues become unreliable, environmental change can cause deleterious effects regardless of the populations evolutionary history. Overall, this work provides a general framework for understanding the role of plasticity in population responses to rapid environmental change.

evolutionary biology↗

bioRxiv2022

Extinction Risk of Sonoran Desert Annuals Following Potential Changes in Precipitation Regimes

Rapid environmental change can affect both the mean and variability in environmental conditions. Natural selection tends to favour those organisms that best respond to such changes. Here, we consider delayed germination as bet hedging strategies for 10 Sonoran Desert annuals. We use a germination model parameterized with long-term demographic and climate data to explore potential effects of changes in the mean and variance in precipitation on the evolution of germination strategies, as well as the risk of extinction. We then explored the potential for evolutionary rescue in response to these changes. As expected, results indicate that as rainfall declines, or uncertainty in rainfall increases, all species have higher extinction risk (the former being more detrimental). These shifts also increased the benefit of delayed germination. Results also indicate that evolutionary rescue can often occur for small shifts, especially for more variable rainfall regimes, but would not likely save populations experiencing larger environmental changes. Finally, we identified life history traits and functional responses to precipitation that were most strongly correlated to the ability to cope with changes in rainfall and with potential for evolutionary rescue: dormant seed survivorship and, to a smaller degree, chance of reproduction and seed yield sensitivity to precipitation.

ecology↗

bioRxiv2018

Rapid environmental change in games: complications and curiosities

Human-induced rapid environmental change (HIREC) has recently led to alterations in the fitness and behavior of many organisms. Game theory is an important tool of behavioral ecology for analyzing evolutionary situations involving multiple individuals. However, game theory bypasses the details by which behavioral phenotypes are determined, taking the functional perspective straight from expected payoffs to predicted frequencies of behaviors. In contrast with optimization approaches, we identify that to use existing game theoretic models to predict HIREC effects, additional mechanistic details (or assumptions) will often be required. We illustrate this in relation to the hawk-dove game by showing that three different mechanisms, each of which support the same ESS prior to HIREC (fixed polymorphism, probabilistic choice, or cue dependency), can have a substantial effect on behavior (and success) following HIREC. Surprisingly, an increase in the value of resources can lead to a reduction in payoffs (and vice versa), both in the immediate- and long-term following HIREC. An increase in expected costs also increases expected payoffs. Along with these counter-intuitive findings, this work shows that simply understanding the behavioral payoffs of existing games is insufficient to make predictions about the effects of HIREC.\n\nIts the little details that are vital. Little things make big things happen.\n\nJohn Wooden

animal behavior and cognition↗