Biology subjects

Learmonth, R.

Publications and source records attributed to Learmonth, R..

4 recordsLinked to original sources

bioRxiv2026

Carry-over effects and plasticity to temperature shape phenology across life stages and generations

Climate change is advancing spring phenology in temperate systems, with the potential to disrupt synchrony between trophic levels. Predicting these shifts requires understanding not only direct plastic responses to temperature, but also how plasticity at one stage carries over to shape timing at subsequent stages. We experimentally quantified direct thermal plasticity in phenology and its carry-over effects across the full life cycle of the winter moth (Operophtera brumata), a holometabolous insect whose fitness relies on synchrony with host plant budburst. Using a fully factorial split-clutch rearing experiment across four temperature treatments, we exposed individuals to contrasting conditions at each life stage and used structural equation modelling to partition direct and carry-over effects on phenology. Each life stage showed distinct plastic responses to temperature. Carry-over effects transmitted approximately 0.38 days/day of plastic advance to the next life stage on average, with the remainder absorbed by compensatory changes in the duration of the subsequent life stage. Together, these results show that carry-over effects propagate plastic responses across the life cycle, which are partially buffered by compensatory changes in developmental duration. Accurate predictions of phenological shifts under climate change therefore require models that account for carry-over effects and developmental compensation across life stages.

ecology↗

bioRxiv2026

Carryover effects modulate spring phenological responses to temperature in a herbivorous insect

O_LIPhenological shifts are a major ecological consequence of climate change, yet studies often focus on single life stages meaning that the potential for carryover effects between life stages remains poorly understood. Failing to account for these effects may lead to inaccurate estimates of phenological shifts, with consequences for predicted synchrony among interacting species. This is especially relevant for temperate systems where climate warming is occurring unevenly across the year. C_LIO_LIHere, we investigated how temperature experienced the previous autumn and winter (during the pupal and egg stage) influences spring phenology in the winter moth (Operophtera brumata), a herbivorous insect with distinct life stages. Using 50 years of local climate data to create five experimental temperature regimes, we first quantified phenotypic plasticity in the duration and temporal variability of pupal and egg development. We then examined how timing of adult moth emergence affects timing of offspring hatching. C_LIO_LIWe found divergent effects of temperature on different life stages; pupal development time was shortest at intermediate temperatures while egg development time decreased linearly with increasing temperature. Furthermore, phenological shifts due to the conditions experienced by the mother were carried over to influence the phenology of her offspring. While this carryover effect was partially compensated during subsequent stages, compensation decreased under warming conditions. C_LIO_LIThese results refine our understanding of the sensitivity of the annual cycle of winter moth phenology to variation in temperature with potential implications for population dynamics and interspecific interactions. Overall, our findings highlight the need to consider the impacts of warming across multiple life stages so that carryover effects can be properly accounted for. Doing so will improve predictions of phenological shifts under future climates. C_LI

ecology↗

bioRxiv2025

Integrative analysis of fine-scale local adaptation of winter moths to variable oak phenology

For herbivorous insects whose fitness depends on tight phenological synchrony with host plants, spatial variation in plant phenology can impose strong selective pressures and promote local adaptation to host timing. These dynamics are central to predicting how species will respond to environmental change, particularly climate-driven shifts in plant phenology. The winter moth (Operophtera brumata) relies on synchronising larval egg hatch with leaf budburst of deciduous trees, yet whether they are locally adapted to their hosts phenology, and their capacity to track future change, remains unclear. Here, we investigated potential small-scale local adaptation of winter moths to oak tree phenology in Wytham Woods, UK, a 385-hectare woodland, within which oak budburst can vary by up to three weeks within a given year. We conducted laboratory temperature manipulation experiments using 76 clutches across six temperature treatments, and field translocation experiments using over 200 clutches. We combined these experiments with assessment of population structure from whole-genome sequencing of 59 individuals. This integrative approach allowed us to assess local adaptation in terms of phenotypic differences, fitness consequences, and genetic evidence. Temperature manipulations revealed systematic differences in the timing of egg hatching across temperature treatments at the clutch level which were linked to carry-over effects from the mothers emergence time, but unrelated to their source tree budburst timing. Field translocation experiments further showed no significant differences in survival of individuals transplanted to trees with phenology differing from their original host tree, and there was no genetic structure across the population. Together, these results reveal consistent differences in hatching phenology despite the absence of population structure, strong selection, or accordance with relative tree phenology. Our findings advance our understanding of the mechanisms maintaining close synchrony in trophic interactions at small scales, which may drive spatial variation in evolutionary responses to future climate change.

evolutionary biology↗

bioRxiv2025

Using landscape biodiversity metrics to assess rewilding: a space-for-time comparison between the Knepp Estate and an agricultural baseline at Boothby Wildland

O_LIThe biodiversity crisis is often framed in terms of the reduction of species found at a site: a (alpha) diversity. However, changes in species composition across a landscape - b (beta) diversity - caused by biotic homogenisation are part of the same crisis. Much biotic homogenisation in British terrestrial landscapes in the post-war period (1945 onwards) has been driven by agricultural conversion and intensification. Restoration efforts must therefore contend with restoring agricultural land to some desired state, and rewilding has emerged as a potential solution to this problem. C_LIO_LIHere we quantify rewilding success by comparing a- and b-diversity of plant assemblages across two study systems in different stages of rewilding. Boothby Wildland is an arable farm recently given over to rewilding, while the Knepp Estate is an ex-arable and dairy farm currently >20 years into rewilding. We assessed a-diversity within, and b- diversity across, these two landscapes using 3 years of plant survey data (2022-2024). C_LIO_LIWe confirmed expected differences between a baseline and rewilded landscape and explored the changes in a brand new rewilded landscape in its early years of progress. As expected, the plant community at the Knepp Estate is relatively stable while that of Boothby Wildland is changing rapidly, and we discuss the landscape impacts of different herbivory regimes on recovery. C_LIO_LISynthesis and applications. We also show that spatial metrics for SESMPD and SESMNTD can distinguish between a rewilded and degraded landscape. This suggests that changes in the structure of biodiversity across landscapes can be quantified using analyses that account for spatial structure in metrics. We call for further research to see if a spatial approach of this kind can be used as a general metric of success in rewilding. C_LI

ecology↗