Biology subjects

Nicholls, E.

Publications and source records attributed to Nicholls, E..

8 recordsLinked to original sources

bioRxiv2026

Behavioural flexibility masks delayed costs of environmental instability

Environmental predictability influences the value of information acquired through experience, yet relatively little is known about how instability in resource characteristics influences behavioural organisation during foraging. We tested whether repeated changes in floral orientation, a manipulation of environmental predictability, affect pollen foraging in bumblebees (Bombus terrestris) by exposing naive workers to either stable floral conditions (single flower orientation) or repeated inter-trial changes in flower orientation (three alternating flower orientations), under constant resource availability. We quantified pollen collection, foraging efficiency, revisitation behaviour, floral coverage and sonication behaviour across three successive foraging trials of either constant or variable flower orientation, before assessing performance in a common post-treatment preference test in which bees were offered all three flower orientations and higher pollen rewards. Environmental instability altered the organisation of foraging behaviour. Bees exposed to unstable floral conditions progressively reduced flower revisitation behaviour and were less likely to perform sonication, although floral coverage, defined as the number of unique flowers visited, remained unchanged. Contrary to our predictions, instability had only weak immediate effects on pollen acquisition and foraging efficiency compared to bees tested under stable conditions. However, previous exposure to instability generated carry-over effects in the common post-treatment preference test. Bees previously exposed to unstable conditions were significantly less likely to return with pollen and consequently collected less pollen overall than bees previously exposed to stable conditions. Our results demonstrate that environmental instability can influence pollen foraging in ways that are not captured by immediate measures of performance. Although behavioural adjustments appeared to buffer short-term consequences during repeated foraging trials, carry-over effects were evident when bees were later tested in a common high-reward, multi-orientation floral array. These findings highlight the importance of considering both behavioural flexibility and carry-over effects when evaluating how organisms respond to changing environments.

animal behavior and cognition↗

bioRxiv2026

Warming limits energetic investment in feeding and post-feeding metabolism in bumblebees

Environmental warming is generally expected to increase metabolic demand in ectotherms. However, facultatively endothermic insects such as bumblebees regulate body temperature and may reduce thermogenic investment under warm conditions, potentially altering physiological performance and responses to climate change. We combined flow-through respirometry and infrared thermography to test how elevated ambient temperature (25 vs 35{degrees}C) affects feeding energetics and postprandial metabolism in the bumblebee Bombus terrestris. Bees maintained substantially lower thoracic temperature excess at 35{degrees}C than at 25{degrees}C, both before and during feeding. Feeding metabolic rate was also lower at 35{degrees}C and was strongly positively associated with thoracic temperature excess, indicating that feeding energetics were primarily explained by thermoregulatory state rather than ambient temperature alone. Elevated temperature reduced both the probability and energetic magnitude of specific dynamic action (SDA), including total SDA expenditure, early postprandial metabolism, and peak metabolic amplitude. In contrast, SDA duration and time to peak response showed little temperature dependence. Our results demonstrate that warming can suppress energetic expenditure in facultatively endothermic pollinators by limiting thermogenic investment and postprandial metabolic responses, potentially constraining the energetic flexibility underpinning foraging performance under climate warming.

physiology↗

bioRxiv2025

MetaBeeAI: an AI pipeline for full-text systematic reviews in biology

The volume and complexity of scientific literature are expanding rapidly, making it increasingly difficult to extract and synthesise information across studies. This challenge is particularly acute in the biological sciences, where evidence spans multiple levels of organisation and heterogeneous experimental designs. Large Language Model (LLM) pipelines offer a scalable route to evidence synthesis, but many existing approaches lack transparency, modularity, and effective mechanisms for human oversight. We present MetaBeeAI, an open-source, modular pipeline that integrates established LLM techniques into a coherent, auditable workflow for structured data extraction in biology. MetaBeeAI combines modular prompting, multi-pass extraction, and expert-in-the-loop validation within an interface that presents model outputs alongside source text, enabling inspection, correction, and iterative refinement. The pipeline produces machine-readable records of prompts, configurations, and expert annotations, supporting reproducibility and continuous improvement. We apply MetaBeeAI to 924 research papers on bees and pesticides, extracting structured information on species, compounds, exposure designs, and experimental context. Evaluation demonstrates improved consistency, convergence with expert judgement, and robustness across heterogeneous biological studies, highlighting the value of expert-guided refinement. MetaBeeAI provides a transparent and extensible framework for scalable evidence synthesis, supporting reliable integration of LLMs into biological research workflows.

ecology↗

bioRxiv2025

First direct quantification of floral handling costs in bees

Floral handling can be energetically costly for bees, yet these costs are rarely measured. We provide the first direct quantification of the metabolic cost of floral buzzing in bumblebees and evaluate its ecological significance. Using flow-through respirometry synchronised with laser vibrometry, we measured carbon dioxide production during buzzing by Bombus terrestris and compared it with flight take-off, which is powered by the same thoracic muscles. Buzzing required high muscular effort, with [~]0.10 J per event and mass-specific power [~]293 W kg-{superscript 1}, and overall costs comparable to take-off because buzzing bouts are longer even though the metabolic rate is lower. Absolute metabolic rate increased with body mass, whereas intertegular span did not, implying that transient load rather than structural size better explains energetic demand in short, high-intensity behaviours. Metabolic traits were repeatable within individuals, and colony identity explained additional variance, consistent with genetic or shared environmental effects. Converting costs to nectar equivalents showed that buzzing required slightly more nectar than take-off and that requirements rose as nectar sugar concentration declined. We conclude that floral buzzing is a major, previously unquantified component of bee energy budgets that is likely to shape nectar supplementation, flower sequencing, and plant-pollinator interaction strength.

animal behavior and cognition↗

bioRxiv2024

Shifts in honeybee worker metabolism immediately post-eclosion

O_LIThe metabolic rate of an organism is intrinsically linked to key traits such as reproductive output and lifespan. While the drivers of individual differences in metabolic rate are poorly understood, previous research in insects has shown that metabolic rate can change substantially in the initial hours and days post-eclosion as adults. C_LIO_LIHere we repeatedly measured the resting and active metabolic rate of individual adult honeybees (Apis mellifera) for up to 48 hours from the time of eclosion. We combined flow-through respirometry with automated behaviour tracking, permitting us to obtain active (AMR) and true resting metabolic rate (RMR) from freely moving animals. We compared these recordings to the more conventional approach of obtaining resting metabolic rate by restraining animals. C_LIO_LIBoth active and resting metabolic rates and mass-specific metabolic rates increased significantly in the first 48-hours post-eclosion, whereas metabolic scope did not change. Mass-specific water loss was highest in active bees and changed non-linearly with time post-eclosion, increasing in the first 24 hours before decreasing again. A similar quadratic relationship with time was also observed for bees movement speed. Speed- and mass-specific metabolic rate and scope increased with time post-emergence, whereas speed- and mass-specific water loss did not. C_LIO_LIThe metabolic rate of restrained bees was consistently significantly higher than the true RMR at all time points, likely due to the stress associated with being restrained. Therefore, we recommend future studies of insect resting metabolic rates avoid restraining organisms to restrict movement and consider employing behaviour tracking as a means to extract metabolic rate data from periods of true rest. C_LIO_LIThis study provides important insights into the previously overlooked changes in metabolism exhibited by newly emerged honeybee workers. The high mortality rate beyond 48 hours, coupled with significant changes in metabolic rates, body mass, and water loss, underscores the importance of this early post-eclosion period for survival and metabolic stabilization. C_LI

physiology↗

bioRxiv2024

Gustatory sensitivity to amino acids in bumblebees

Bees rely on amino acids from nectar and pollen for essential physiological functions. While nectar typically contains low (<1 mM) amino acid concentrations, while their levels in pollen are higher, but vary widely (10-200 mM). Behavioural studies suggest bumblebees have preferences for specific amino acids but whether such preferences are mediated via gustatory mechanisms remains unclear. This study explores bumblebees (Bombus terrestris) gustatory sensitivity to two essential amino acids (EAAs), valine and lysine, using electrophysiological recordings from gustatory sensilla on their mouthparts. Valine elicited a concentration-dependent response from 0.1 mM, indicating that bumblebees could perceive valine at concentrations found naturally in nectar and pollen. In contrast, lysine failed to evoke a response across tested concentrations (0.1-500 mM). The absence of lysine detection raises questions about the specificity and diversity of amino acid-sensitive receptors in bumblebees. Bees responded to valine at lower concentrations than sucrose, suggesting comparatively higher sensitivity (EC50: 0.7 mM vs. 3.91 mM for sucrose). Our findings indicate that bumblebees can rapidly evaluate the amino acid content of pollen and nectar using pre-ingestive cues, rather than relying on post-ingestive cues or feedback from their nestmates. Such sensory capabilities likely impact foraging strategies, with implications for plant-bee interactions and pollination.

neuroscience↗

bioRxiv2024

Understanding pollination in urban food production: the importance of data validation and participant feedback for citizen science project design

O_LIThere is a significant knowledge gap regarding the pollination needs of urban farming, partly due to barriers for researchers in accessing these growing spaces. Involving growers in data collection offers a potential solution but presents other challenges in terms of data accuracy and participant retention. C_LIO_LIWe developed a citizen science methodology for monitoring plant-pollinator interactions in urban food systems and evaluated the accuracy of data collected by growers by comparison to data collected by a professionally trained researcher. We also collected feedback from participants at the mid- and endpoints of the project regarding their experiences of taking part. C_LIO_LIWhile there was some agreement between the datasets in terms of the crops most (raspberries and squash) and least attractive (tomatoes) to insects, relying only on the dataset collected by growers themselves (citizen scientists) would lead to an overestimation of the generality of relationships between crops and pollinating insects in urban food production. Possible reasons for discrepancies between the datasets include species misidentification and non-reporting of surveys where no insects were observed by citizen scientists. C_LIO_LICitizen scientists reported lack of time, concerns about data accuracy and too complex methods as barriers to participation. Implementation of their suggestions for improvements led to a 66% increase in participation in the following year, demonstrating the importance of maintaining a two-way dialogue between participants and project organisers. Citizen scientists also reported an increased appreciation and understanding of insect pollinations following participation, highlighting an additional benefit of involving urban growers in data collection. C_LI Social Impact StatementGrowing food in urban areas can contribute towards sustainable food production. We know little about urban crop pollination, and data collection can be challenging due to restricted access to growing spaces. We developed and tested the effectiveness of a method for urban growers themselves to collect data on insects visiting their crops. Comparing data to that collected by a professional researcher, we found similarities in terms of the most and least attractive crops to pollinators, but there were also large discrepancies in the datasets that mean there are limitations to relying on grower-collected data alone to understand urban plant-pollinator interactions.

ecology↗

bioRxiv2021

Larval nutrition impacts survival to adulthood, body size, and the allometric scaling of metabolic rate in adult honeybees

Resting metabolic rate (RMR) is a fundamental physiological measure linked to numerous aspects of organismal function, including lifespan. Although dietary restriction in insects during larval growth/development affects adult RMR, the impact of larval diet quality on adult RMR has not been studied. Using in vitro rearing to control larval diet quality, we determined the effect of dietary protein and carbohydrate on honeybee survival-to-adulthood, time-to-eclosion, body mass/size and adult RMR. High carbohydrate larval diets increased survival-to-adulthood and time-to-eclosion compared to both low carbohydrate and high protein diets. Upon emergence, bees reared on the high protein diet were smaller and lighter than those reared on other diets, whilst those raised on the high carbohydrate diet varied more in body mass. Newly emerged adult bees reared on the high carbohydrate diet showed a significantly steeper increase in allometric scaling of RMR compared to those reared on other diets. This suggests that diet quality influences survival-to-adulthood, time-to-eclosion, and the allometric scaling of RMR. Given that agricultural intensification and increasing urbanisation have led to a decrease in both forage availability and dietary diversity for bees, our results are critical to improving understanding of the impacts of poor developmental nutrition on bee growth/development and physiology. Summary statementWe show, for the first time, that the nutritional quality of insect larval diets affects the scaling of metabolic rate with body mass in newly emerged adult honeybees.

physiology↗