Biology subjects

Shlichta, J. G.

Publications and source records attributed to Shlichta, J. G..

3 recordsLinked to original sources

bioRxiv2025

Climate change induced selection on and evolution of insect thermal sensitivity

How have recent changes in temperature means and variability altered selection on and evolution of the thermal sensitivity of insect growth? We address this question for cabbage white butterflies, Pieris rapae, by repeating a 1999 study that linked lab measurements of the temperature sensitivity of short-term growth rates to fitness components (survival, development time, final body size, and fecundity) in the field. In 1999, selection favored increased growth at low temperatures at the expense of decreased growth at high temperatures. We document evolution consistent with this past selection: caterpillars now grow faster at low temperatures but slower at warm temperatures in 2024 compared to 1999. However, temperatures have changed rapidly, with increasing incidence of high temperatures such that selection in 2024 has reversed to favor increased growth at the highest temperature assayed. Over the 25 years, phenotypic variation has increased at warm temperatures and a tradeoff between growth at intermediate and warm temperatures has strengthened, consistent with evolutionary constraints that may restrict evolution to grow faster at rare, high temperatures. Our study demonstrates the potential for rapid evolution of thermal sensitivity in response to climate change in an agricultural pest. However, selection to initially capitalize on warming temperatures can ultimately decrease fitness as warming temperatures move into a stressful range, driving reversals in the direction of selection.

ecology↗

bioRxiv2023

Heat stress and the temporal dynamics of insect growth

Temperature affects rates of ingestion, growth and other key processes in insects and other ectotherms, a relationship described by the thermal performance curve. But the history of temperature exposure can cause stress or acclimation responses, altering the relationship between current temperature and performance. The temporal dynamics of such time-dependent effects for ectotherm growth are poorly understood. We quantify how growth and ingestion change over time at different constant temperatures during the final larval instar for two thermal-generalist insect species, Pieris rapae L. and Manduca sexta L. Initial growth rates were greatest at higher temperatures for both P. rapae (29-35 {degrees}C) and M. sexta (34-38 {degrees}C); but growth rates at higher temperatures declined over time. As a result, the optimal and maximal temperatures for growth declined over time (2-4 days) in both species. Unlike P. rapae, M. sexta could maintain growth and survival to wandering and pupation at temperatures above 35 {degrees}C. For M. sexta larvae at 40 {degrees}C, ingestion continues even as growth declines, suggesting that post-ingestive processes limit growth rates at these high temperatures. Our results show how time-dependent effects at higher temperatures develop over hourly to daily time scales, with important consequences for understanding and modeling organismal responses to heat waves and extreme temperature events.

ecology↗

bioRxiv2022

Public exams provide opportunities for deeper thought with less anxiety

Assessment methods across post-secondary STEM education are traditionally constrained by logistics and likely contribute to the widespread inequities in STEM education outcomes. As part of attempts to improve and diversify the methods used in assessment, the authors have developed a flexible and low-tech style known as public exams based in educational best practices. Public exams attempt to authentically involve students into the process of assessment through the use of pre-released portions of the exam. Using mixed-methods research techniques at a closely matched pair of institutions (a research-intensive university and a community college classroom), we observed signals of positive impact from the public exam on student learning experiences. Public exams appear to promote deeper thought, to direct students more efficiently to the core concepts in the discipline, and to decrease student anxiety around exams. The public exam experience does not show evidence for exacerbating gaps in exam outcomes for students from underrepresented backgrounds. This suggests that public exams are worth deeper investigation as an evidence-based and effective assessment style.

scientific communication and education↗