Biology subjects

Cole, E. F.

Publications and source records attributed to Cole, E. F..

15 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

Vertical Variation of the Caterpillar Community in Oak (Quercus robur) Canopies

1) BackgroundUnderstanding how caterpillar communities vary within tree canopies is key to interpreting forest trophic dynamics and responses to environmental change, yet such variation remains poorly quantified due to the challenges of sampling in three dimensions. 2) AimsWe quantified within-canopy heterogeneity in caterpillar densities, diversity, and herbivory and explored relationships with host tree phenology and commonly used ground-based monitoring approaches. 3) MethodsUsing direct canopy access, we sampled branches from lower, middle, and upper canopy strata of 34 mature pedunculate oaks (Quercus robur) in Wytham Woods, UK, during the spring abundance peak over three consecutive years (2023-2025). We tested for vertical stratification in caterpillar community metrics, examined patterns in early instar distributions at emergence, assessed associations with host tree phenology across spatiotemporal scales, and evaluated how well ground-based methods (water and frass traps) reflect canopy communities. 4) ResultsVertical stratification was modest but varied among years: densities and species richness increased with canopy height in 2023, decreased in 2024, and were uniformly low across strata in 2025. Although within-crown budburst timing varied systematically, with upper branches bursting approximately two days earlier than lower branches, tree phenology did not explain within- or between-year variation in caterpillar communities. Frass trap data correlated moderately well with canopy caterpillar densities, whereas water traps showed weaker and less consistent relationships, reflecting behavioural and methodological biases. 5) ConclusionsCaterpillar communities showed no consistent patterns of vertical stratification across years, instead they are shaped more strongly by inter-annual and tree-level variation. Integrating targeted canopy sampling with scalable ground-based proxies could greatly improve monitoring of arboreal Lepidoptera and inform studies of trophic synchrony and wood-land resilience under environmental change.

ecology↗

bioRxiv2026

Fine-scale spatio-temporal variation in natural selection on reproductive traits across two wild bird species

Natural selection drives adaptive evolution and underpins eco-evolutionary processes. However, the causes of variation of selection (strength and direction), and its spatio-temporally scaling, remain poorly understood. Most selection estimates are population-wide, ignoring the variation in fine-scale selection regimes within populations. We quantify variation in selection within sub-populations of a long-term study of great tits (Parus major) and blue tits (Cyanistes caeruleus) in Wytham Woods, UK. Using mixed-effect modelling, we decomposed temporal, spatial and spatio-temporal variation in selection on laying date, clutch size and their correlational selection. Across species, we detected non-linear selection for larger clutch size and earlier laying, and negative correlational selection. Spatio-temporal effects explained most variation in selection across traits and species, suggesting that the causes of selection are controlled by interacting temporal (e.g. climate) and spatial (e.g. habitat) mechanisms. Laying date had strong temporal (among-year) variation for both species, whereas spatial components generally explained little variation. Selection estimates were highly correlated between species for all traits except for correlational selection, with higher agreement when analyzing fledgling versus recruitment numbers. Our results suggest common factors underpinning small-scale spatio-temporal variation in selection in both species and that such analyses can identify the sources causing natural selection.

ecology↗

bioRxiv2026

Not-so-great tits: early-life environment drives long-term decrease in adult body mass in a wild bird population

Body mass is a key organismal characteristic that impacts many physiological and ecological processes and often a strong determinant of fitness. Recent studies have documented temporal phenotypic changes in this trait in many populations, but identifying the mechanisms underpinning these changes can be difficult. Here, we use 47 years of data to analyse how adult and nestling body mass have changed over time in a great tit Parus major population in Wytham Woods (UK). Further, we link those changes to three environmental variables previously recognised as drivers of body mass: temperature, intra- and inter-specific competition and temporal mismatch with a key prey during breeding, winter moth Operophtera brumata caterpillars. Temporal analyses of adult body mass revealed contrasting dynamics at the between- and within-cohort levels, mirroring Simpsons Paradox. At the population level we report a marked decrease in body mass in adults between 1978 and 2024 (-0.042 Haldanes), and show that this results from phenotypic plasticity, driven by a negative between-cohort trend likely reflecting carry-over effects of the early environment. Within cohorts, however, trends were consistently positive likely reflecting an age-dependent mass increase. The change in adults was paralleled by a change in nestling body mass (-0.036 Haldanes). Nestling mass was negatively associated with estimated intensity of intraspecific competition, as well as inter-specific competition from blue tits Cyanistes caeruleus, as quantified by local population density. These effects carried over to adulthood, as shown by a negative association between adult mass and the population density experienced at early life. Temperature during development and mismatch with the caterpillar food supply, despite being associated with adult and nestling mass, did not explain the observed declines in mass, largely because these have not changed over time. Overall, our results illustrate the potential for effects mediated early in development to carry-over into long-term phenotypic change at later life history stages, and emphasise the value of considering multiple effects as drivers of phenotypic change in natural populations.

evolutionary biology↗

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

Quantifying phenology in the deciduous tree and phytophagous insect system: a methodological comparison

The extent to which phenological synchrony between trophic levels may be disrupted by environmental change has been a topic of increased focus in recent years. Phenological associations between deciduous trees, phytophagous insects and their consumers (e.g. passerine birds) have become one of the model systems for understanding this process. However, most existing research reports population-level associations rather than examining the smaller spatial scales at which these trophic interactions occur. Furthermore, a variety of methods have been used to measure phenology, particularly on producers and primary consumers, with little formal comparison. To investigate how different methods of measuring producer and primary consumer phenology influence our understanding of these biological relationships at the appropriate scale, we quantified phenological metrics for individual host trees and the phytophagous insects that depend on them in a deciduous woodland during spring 2023. We sampled 170 trees from six deciduous species in Wytham Woods, UK, deriving nine metrics of phenology from five distinct field methods: multispectral drone imaging (NDVI), hemispherical canopy photography, and bud-scoring observations to track tree phenology, as well as water traps and frass traps to monitor insect herbivore phenology. We assessed the reliability of these methods within both trophic levels and across tree species. We further evaluated the extent to which tree phenology metrics correlated with herbivore phenology, at the level of individual trees, and links to variation in subsequent herbivory rates across a subsample of 72 oak trees (Quercus robur). Our results illustrate how methodological choices can affect our ability to study the timing of trophic interactions and reveal finescale spatiotemporal variation in phenology across both trophic levels. We discuss the implications of these results for considering how the scale-dependence of trophic interactions may stabilise populations and shape broader-scale responses to environmental change.

ecology↗

bioRxiv2024

Optimal thermal niche-tracking buffers wild great tits against climate change

Animal and plant populations are responding to climate change by shifting the timing of key seasonal events. However, while measuring responses of natural systems on human calendars provides a standard scale of measurement it reveals little about the underlying biological causes and mechanisms of change. Here, using data from a six decade longitudinal, individual-based, study of great tits Parus major, we show that changing the timing of breeding has enabled birds to track specific temperatures at different stages in reproduction. We show, further, that multiple measures of reproductive success are maximised at intermediate, stage-specific, temperatures that correspond to the temperatures tracked while climate has changed in recent decades. Finally, we show that tracking temperatures has allowed great tits to match reproduction with a key food source for nestling development, the winter moth Operophtera brumata. Consequently, phenotypic plasticity in reproductive timing has enabled great tits to track temporal changes in the environmental conditions that maximise individual reproductive success. Shifting our perspective from analysing the phenological timing of life history events under climate change to analysing changes relative to environmental gradients has the potential to shed new light on the causes, mechanisms, and consequences of these shifts.

evolutionary biology↗

bioRxiv2024

Continent-wide drivers of spatial synchrony in age structure across wild great tit populations

Spatio-temporal variation in age structure influences population dynamics, yet we have limited understanding of the spatial scale at which its fluctuations are synchronised between populations. Using 32 great tit populations, spanning 3200km and >130,000 birds across 67 years, we quantify spatial synchrony in breeding age structure and its drivers. We show that larger clutch sizes, colder winters and summers, and larger beech crops lead to younger populations. We report distant-dependent spatial synchrony of age structure, which is maintained at approximately 650km. Despite covariation with age structure, reproductive and environmental variables do not influence the scale of synchrony, except for a moderate effect of beech masting. We suggest that local ecological and density-dependent dynamics impact how environmental variation interacts with age structure, influencing estimates of the environments effect on spatial synchrony. Our analyses demonstrate the operation of synchrony in age structure over large scales, with implications for age-dependent demography in populations.

ecology↗

bioRxiv2024

Age-specificity in territory quality and spatial structure in a wild bird population

Age influences behaviour, survival, and reproduction; hence variation in population age structure can affect population-level processes. The extent of spatial age structure may be important in driving spatially-variable demography, particularly when space-use is linked to reproduction, yet it is not well understood. We use long-term data from a wild bird population to examine spatial age structure and quantify covariance between territory quality and age. We find associations between age and aspects of territory quality, but little evidence for spatial age structure compared to territory quality and reproductive structure. We also report little between-year repeatability of spatial age structure compared to structure in reproductive output. We suggest that high breeding site fidelity and frequent territory turnover by younger breeders, driven by high mortality and immigration rates, limits the association between age and territory quality and weakens overall spatial age structure. Greater spatial structure and repeatability in reproductive output compared to age suggests that habitat quality may be more important in driving spatially-variable demography than age in this system. We suggest that the framework developed here can be used in other taxa to assess spatial age structure, particularly in longer-lived species where we predict from our findings there may be greater structure.

ecology↗

bioRxiv2024

Environmental similarity between relatives reduces heritability of reproductive timing in wild great tits

Intraspecific variation is necessary for evolutionary change and population resilience, but the extent to which it contributes to either depends on the causes of this variation. Understanding the causes of individual variation in traits involved with reproductive timing is important in the face of environmental change, especially in systems where reproduction must coincide with seasonal resource availability. However, separating the genetic and environmental causes of variation is not straightforward, and there has been limited consideration of how small-scale environmental effects might lead to similarities between individuals that occupy similar environments, potentially biasing estimates of genetic heritability. In ecological systems, environments can often be complex in their spatial structure, and it may therefore be important to account for similarities in the environments experienced by individuals within a population beyond considering spatial distances alone. Here, we construct multi-matrix quantitative genetic animal models using over 11,000 breeding records (spanning 35 generations) of individually-marked great tits (Parus major) and information about breeding proximity and habitat characteristics to quantify the drivers of variability in two key seasonal reproductive timing traits. We show that the environment experienced by related individuals explains around a fifth of the variation seen in reproductive timing, and accounting for this leads to decreased estimates of heritability. Our results thus demonstrate that environmental sharing between relatives can strongly affect estimates of heritability and therefore alter our expectations of the evolutionary response to selection.

evolutionary biology↗

bioRxiv2023

The demographic drivers of cultural evolution in bird song: a multilevel study

Social learning within communities sometimes leads to behavioural patterns that persist over time, which we know as culture. Examples of culture include learned bird and whale songs, cetacean feeding techniques, and avian and mammalian migratory routes. Shaped by neutral and selective forces, animal cultures evolve dynamically and lead to cultural traditions that differ greatly in their diversity and stability. These cultural traits can influence individual and group survival, population structure, and even inform conservation efforts, underscoring the importance of understanding how other population processes interact with social learning to shape culture. Although the impact of social learning mechanisms and biases has been extensively explored, the role of demographic factors--such as population turnover, immigration, and age structure--on cultural evolution has received theoretical attention but rarely been subject to empirical investigation in natural populations. Doing so requires very complete trait sampling and detailed individual life history data, which are hard to acquire in combination. To this end, we built a multi-generational dataset containing over 109,000 songs from >400 individuals from a population of Great Tits (Parus major), which we study using a deep metric learning model to re-identify individuals and quantify song similarity. We show that demographic variation at the small spatial scales at which learning takes place has the potential to strongly impact the pace and outcome of animal cultural evolution. For example, age distributions skewed towards older individuals are associated with slower cultural change and increased diversity, while higher local population turnover leads to elevated rates of cultural change. Our analyses support theoretical expectations for a key role of demographic processes resulting from individual behaviour in determining cultural evolution, and emphasize that these processes interact with species-specific factors such as the timing of song acquisition. Implications extend to large-scale cultural dynamics and the formation of dialects or traditions.

animal behavior and cognition↗

bioRxiv2023

A densely sampled and richly annotated acoustic dataset from a wild bird population

We present a high-resolution, densely-sampled dataset of wild bird songs collected over multiple years from a single population of Great Tits (Parus major) in the UK. The dataset includes over 1,100,000 individual acoustic units from 109,963 richly annotated songs, sung by more than 400 individual birds, and provides unprecedented detail on the vocal behaviour of wild birds. Here, we describe the data collection and processing procedures and provide a summary of the data. We also discuss potential research questions that can be addressed using this dataset, including behavioural repeatability and stability, links between vocal performance and reproductive success, the timing of song production, syntactic organisation of song production, and song learning in the wild. We have made the dataset and associated software tools publicly available with the aim that other researchers can benefit from this resource and use it to further our understanding of bird vocal behaviour in the wild.

animal behavior and cognition↗

bioRxiv2019

Information use in foraging flocks of songbirds - no evidence for social transmission of patch quality

Animals use behavioural cues from others to make decisions in a variety of contexts. There is growing evidence, from a range of taxa, that information about the locations of food patches can spread through a population via social connections. However, it is not known whether information about the quality of potential food sources transmits similarly. We studied foraging behaviour in a population of wild songbirds with known social associations, and tested whether flock members use social information about the profitability of patches to inform their foraging decisions. We provided artificial patches (ephemeral bird feeders) that appeared identical but were either profitable (contained food) or unprofitable (contained no food). If information about patch profitability spreads via social associations, we predicted that empty feeders would only be sampled by individuals that are less connected to each other than expected by chance. In contrast, we found that individuals recorded at empty feeders were more closely associated with each other than predicted by a null model simulating random arrival of individuals, mirroring pattern of increased connectedness among individuals recorded at full feeders. We then simulated arrival under network-based diffusion of information, and demonstrate that the observed pattern at both full and empty feeders matches predictions derived from this post-hoc model. Our results suggest that foraging songbirds only use social cues about the location of potential food sources, but not their profitability. These findings agree with the hypothesis that individuals balance the relative economic costs of using different information, where the costs of personally sampling a patch upon arrival is low relative to the cost of searching for patches. This study extends previous work on information spread through avian social networks, by suggesting important links between how animals use information at different stages of the acquisition process and the emerging population-level patterns of patch use.

animal behavior and cognition↗

bioRxiv2019

Wild songbirds exhibit consistent individual differences in inter-specific social behaviour

AO_SCPCAPBSTRACTC_SCPCAPO_LINatural populations and communities consist of individuals that differ in their phenotypes. There is increasing evidence in community ecology that consistent intraspecific variation in behaviour changes the outcome of ecological interactions.\nC_LIO_LIDifferences in intra- and inter-specific interactions are expected to play a major role in determining patterns of species coexistence and community structure. However, the question of whether individuals vary in their propensity to associate with heterospecifics has been neglected.\nC_LIO_LIWe used social network analysis to characterise pattern of heterospecific associations in wild mixed-species flocks of songbirds, and assessed whether individuals adopt consistent social strategies in their broader, heterospecific, social environment. We quantified heterospecific foraging associations using data from a large automatically monitored PIT-tagged population of birds, involving more than 300 000 observations of flock membership, collected over three winters, for two tit species (Paridae), blue tits, Cyanistes caeruleus, and great tits, Parus major.\nC_LIO_LIWe assessed individual consistency in interspecific social preferences over both short-term (week-to-week) and longer-term (year-to-year) timescales for a total of 4610 individuals, and found that blue tits and great tits exhibited marked and consistent intraspecific differences in heterospecific social phenotypes in terms of both absolute and relative number of associates. Further, we found that these consistent differences were significantly greater than expected from spatial and temporal differences in population densities.\nC_LIO_LIHeterospecific associations represent a major component of the social environment for many species, and our results show that individuals vary consistently in their social decisions with respect to heterospecifics. These findings provide support for the notion that intraspecific trait variation contributes to patterns at community and ecosystem levels.\nC_LI

animal behavior and cognition↗

bioRxiv2018

Experimental manipulation of nocturnal nest cavity temperature in wild blue tits

Advances in the timing of reproduction in temperate species are some of the most well documented biotic responses to increasing global temperatures. However, the magnitude and rate of these advances in timing are not equal across all taxonomic groups. These differences can lead to disruption of interspecific relationships if species respond differently to temperature changes. Understanding the relationship between temperature and phenology is a key step in predicting future population trends for species living in seasonal environments. However, experimentally manipulating temperature in the wild is logistically challenging and has consequently rarely been attempted. In this study we experimentally test whether in-nest temperatures in early spring act as a cue for breeding phenology in a population of wild blue tits (Cyanistes caeruleus). We split nests into three treatments; heated, cooled, and control. In-nest temperature in the heated and cooled boxes was manipulated by an average of {+/-} 0.6 {degrees}C from control temperatures using heating devices and ice packs respectively. We assessed the impact of our experimental manipulation on box occupancy and reproductive timing. We found trends towards earlier phenology in heated nest boxes in addition to a higher occupancy rate in cooled boxes, however neither of these trends was found to be statistically significant. Our ability to distinguish statistical signals was hampered by unexpectedly low occupancy rates across all experimental treatments. Based on the results we cannot say if nocturnal in-nest temperature is an important cue for nest box choice or the timing of laying.

ecology↗