Biology subjects

Monchanin, C.

Publications and source records attributed to Monchanin, C..

3 recordsLinked to original sources

bioRxiv2022

Natural variability in bee brain size and symmetry revealed by micro-CT imaging and deep learning

Analysing large numbers of brain samples can reveal minor, but statistically and biologically relevant variations in brain morphology that provide critical insights into animal behaviour, ecology and evolution. So far, however, such analyses have required extensive manual effort, which considerably limits the scope for comparative research. Here we used micro-CT imaging and deep learning to perform automated analyses of 3D image data from 187 honey bee and bumblebee brains. We revealed strong inter-individual variations in total brain size that are consistent across colonies and species, and may underpin behavioural variability central to complex social organisations. In addition, the bumblebee dataset showed a significant level of lateralization in optic and antennal lobes, providing a potential explanation for reported variations in visual and olfactory learning. Our fast, robust and user-friendly approach holds considerable promises for carrying out large-scale quantitative neuroanatomical comparisons across a wider range of animals. Ultimately, this will help address fundamental unresolved questions related to the evolution of animal brains and cognition. Author SummaryBees, despite their small brains, possess a rich behavioural repertoire and show significant variations among individuals. In social bees this variability is key to the division of labour that maintains their complex social organizations, and has been linked to the maturation of specific brain areas as a result of development and foraging experience. This makes bees an ideal model for understanding insect cognitive functions and the neural mechanisms that underlie them. However, due to the scarcity of comparative data, the relationship between brain neuro-architecture and behavioural variance remains unclear. To address this problem, we developed an AI-based approach for automated analysis of brain images and analysed an unprecedentedly large dataset of honey bee and bumblebee brains. Through this process, we were able to identify previously undescribed anatomical features that correlate with known behaviours, supporting recent evidence of lateralized behaviour in foraging and pollination. Our method is open-source, easily accessible online, user-friendly, fast, accurate, and robust to different species, enabling large-scale comparative analyses across the animal kingdom. This includes investigating the impact of external stressors such as environmental pollution and climate change on cognitive development, helping us understand the mechanisms underlying the cognitive abilities of animals and the implications for their survival and adaptation.

animal behavior and cognition↗

bioRxiv2021

Considering variance in pollinator responses to stressors can reveal potential for resilience

O_LIEnvironmental stressors have sublethal consequences on animals, often affecting the mean of phenotypic traits in a population. However, potential effects on variance are poorly understood. Since phenotypic variance is the basis for adaptation, any influence of stressors may have important implications for population resilience. C_LIO_LIHere we explored this possibility in insect pollinators by analysing raw datasets from 24 studies (6,913 bees) in which individuals were first exposed to stressors and then tested for cognitive tasks. C_LIO_LIWhile all types of stressors decreased the mean cognitive performance of bees, their effect on variance was complex. Focusing on 15 pesticide studies, we found that the dose and the mode of exposure to stressors were critical. At low pesticide doses, cognitive variance decreased following chronic exposures but not for acute exposures. Acute exposure to low doses thus seems less damaging at the population level. In all cases however, the variance decreased with increasing doses. C_LIO_LIPolicy implications. Current guidelines for the authorization of plant protection products on the European market prioritize acute over chronic toxicity assessments on non-target organisms. By overlooking the consequences of a chronic exposure, regulatory authorities may register new products that are harmful to bee populations. Our findings thus call for more research on stress-induced phenotypic variance and its incorporation to policy guidelines to help identify levels and modes of exposure animals can cope with. C_LI

animal behavior and cognition↗

bioRxiv2020

Heavy metal pollutants have additive negative effects on honey bee cognition

Environmental pollutants can exert sublethal deleterious effects on animals. These include disruption of cognitive functions underlying crucial behaviours. While agrochemicals have been identified as a major threat to pollinators, other compounds, such as heavy metals that are often found in complex mixtures, have largely been overlooked. Here, we assessed the impact of acute exposure to field-realistic concentrations of lead, copper, arsenic, and their combinations, on honey bee learning and memory. All treatments involving single metals slowed down appetitive learning and disrupted memory retrieval at 24 h. Importantly, combinations of these metals induced additive negative effects on both processes, suggesting common pathways of toxicity. Our results highlight the need to further assess the risks of heavy metal pollution on invertebrates and to their associated ecosystem services. Summary statementHoney bees displayed reduced learning and memory performances following acute exposure to arsenic, copper or lead. Exposure to combinations of these metals induced additive effects.

animal behavior and cognition↗