Biology subjects

Grainger, T. N.

Publications and source records attributed to Grainger, T. N..

4 recordsLinked to original sources

bioRxiv2025

General predictions for the effects of warming on competition

Understanding the effects of climate change on ecological communities has been limited by a lack of general theory for how temperature affects competition. To fill this knowledge gap, we integrated Modern Coexistence Theory and the Metabolic Theory of Ecology by incorporating empirically-derived temperature sensitivities into Modern Coexistence Theorys central model. We then simulated warming in consumer-resource systems and found that warming reduced both niche and fitness differences, making species more ecologically similar and competitive interactions more neutral. The greatest shifts in competition occurred when temperature sensitivities among species were highly asymmetrical. Effects of warming on competition via niche differences were comparable to those on fitness differences, suggesting that the emphasis on vital rates in global change research may overlook key biodiversity drivers. This general theory expands the domains of two prominent ecological theories and provides predictions for how warming may alter competition even in benign regions of species thermal niches.

ecology↗

bioRxiv2025

Seasonal evolution of Drosophila melanogaster abdominal pigmentation is associated with a multifarious selective landscape

Pigmentation has been widely studied by evolutionary biologists due to both ease of measure and relationship to fitness. Drosophila melanogaster pigmentation has represented a particularly useful avenue of investigation, as extensive genetic tools have enabled the characterization of the traits complex architecture. Drosophila pigmentation also varies predictably across space and time in wild populations, suggesting pigmentation is a component of adaptation to local environmental conditions. Despite this, the impact of D. melanogaster pigmentation on fitness, and the environmental factors that drive the evolution of pigmentation, are not well understood. To address this gap, we experimentally evolved replicated D. melanogaster populations in field mesocosms to determine whether and how pigmentation evolves in response to environmental variation. We found that pigmentation rapidly and predictably adapted to a direct manipulation of temperature, supportive of melanization playing a role in thermoregulation. However, we also determined that pigmentation responded adaptively to direct manipulations of numerous additional factors, including intraspecific competition, diet, and the microbiome. These findings suggest that the selective landscape acting on pigmentation is complex and multifaceted, and that patterns of melanization may be driven, at least in part, by indirect selection due to correlations with other fitness-related traits.

evolutionary biology↗

bioRxiv2018

Cryptic Dispersal Networks Connect Habitat Patches in ways not Captured by Distance

Species interact with the physical world in complex ways, and life history strategies might cause species to differ in how they experience connectedness of the same landscape. As a consequence, dispersal limitation might be present but not captured by distance-based measures of connectivity. To test these ideas, we surveyed plant communities that associate with serpentine soils but differ in dispersal mode (gravity, animal, or wind), and used satellite imagery to quantify forms of landscape connectivity associated with each dispersal mode. Our data yielded two key insights: First, dispersal limitation appeared to be absent using a conventional distance-based measure of connectivity, but emerged after considering forms of landscape connectivity relevant to each dispersal mode. Second, the landscape variables that emerged as important to each dispersal mode were generally consistent with our predictions based on putative dispersal vectors, and included interactive effects that allude to the altered efficacy of animal dispersal in invaded landscapes. Our results have broad implications for understanding how ecological communities reorganize as landscapes are fragmented, patches are lost, and the function of dispersal life histories is altered.

ecology↗

bioRxiv2017

Frequency-dependent Maternal Effects across Species and Environments

O_LIMaternal provisioning of offspring in response to environmental conditions (\"maternal environmental effects\") has been argued as the missing link in plant life histories. Although empirical evidence suggests that maternal responses to abiotic conditions are common, there is little understanding of the prevalence of maternal provisioning in competitive environments.\nC_LIO_LIWe tested how competition in two soil moisture environments affects maternal provisioning of offspring seed mass. Specifically, we varied conspecific frequency from 90% (intraspecific competition) to 10% (interspecific competition) for 15 pairs of annual plant species that occur in California.\nC_LIO_LIWe found that conspecific frequency affected maternal provisioning (seed mass) in 48% of species, and that these responses included both increased (20%) and decreased (24%) seed mass. In contrast, 68% of species responded to competition through changes in per capita fecundity (seed number), which generally decreased as conspecific frequency increased. The direction and magnitude of frequency-dependent seed mass depended on the identity of the competitor, even among species in which fecundity was not affected by competitor identity.\nC_LIO_LISynthesis. Our research demonstrates how species responses to different competitive environments manifest through maternal provisioning, and that these responses alter previous estimates of environmental maternal effects and reproductive output; future study is needed to understand their combined effects on population and community dynamics.\nC_LI

ecology↗