by Yuting Liu, Leiru Huang, Ruipeng Wang, Fukang Qi, Yiwen Liu, Qingyuan Chen, Morgane Mialon, Lili Chen, Berangere Pinan-Lucarre, Shangbang Gao Nicotine exposure elicits diverse behavioral changes, yet the underlying neural pathways and molecular mechanisms remain incompletely understood. Here, we demonstrate that chronic nicotine exposure markedly increases both the initiation and duration of reversals in Caenorhabditis elegans. Strikingly, these reversals were tightly coupled with the rhythmic body contractions of the defecation motor program (DMP). Through pharmacological, genetic, in situ electrophysiological, and calcium imaging analyses, we show that nicotine enhances the activity of the AVA interneuron via selective upregulation of ACR-16, a nicotinic ACh receptor critical for nicotine-induced motor coupling. Ablation of touch receptor neurons (TRNs) or inhibition of TRNs-mediated mechanosensation completely abolished this coupling. Furthermore, optogenetic activation of TRNs in nicotine-treated animals evoked stronger AVA depolarization, and nicotine amplified gentle touch-evoked reversals. Together, these findings reveal a potential interoceptive effect of nicotine mediated by sensitization of the TRNs-AVA mechanosensory pathway, providing new insight into the neural and molecular basis of nicotine’s modulation of sensory-motor coupling.

The important role of pollinators in floral evolution has been well established through centuries of research. A new study combining micrometeorological and behavioral experiments demonstrates that abiotic conditions also play a key role in shaping floral morphology and function in relation to insect visitors.

Ecology and Evolution, Volume 15, Issue 10, October 2025.

Behavioural addictions, characterised by compulsive engagement in rewarding activities despite adverse consequences in the long term, are more heterogeneous and less well-understood than substance addictions, and there is a relative lack of translational research. This study investigates “excessive toy motivation” in domestic dogs as a potential parallel to behavioural addictions in humans. Employing a combination of a behavioural test and an owner questionnaire, we examined whether a subset of highly play-motived dogs meet key behavioural addiction criteria, including craving, salience, lack of self-control, and mood modification. Data from 105 highly play-motivated dogs revealed that 33 subjects exhibited behaviours consistent with addictive-like tendencies, including an excessive fixation on toys, reduced responsiveness to alternative stimuli, and persistent efforts to access toys. Owner-reported behaviours not only corroborated these findings but also demonstrated significant associations with behavioural test scores. Our results highlight parallels between excessive toy motivation in dogs and human behavioural addictions, with dogs as the only non-human species so far that appears to develop addictive-like behaviours spontaneously without artificial induction. This exploratory study provides foundational insights and proposes future research directions that have the potential to significantly deepen our understanding of the psychological mechanisms underlying behavioural addictions across species.

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Abstract Pollinators navigate complex and heterogeneous “flower markets”, where floral resources vary in quality, availability, and spatial distribution. Bumblebees, as generalist foragers, visit numerous flowers during their foraging bouts, yet the factors influencing their flower choices and the individual differences in foraging behaviour remain poorly understood. Here, we tested how bees adjust their foraging in response to different reward structures. Bombus terrestris workers completed three foraging bouts in two artificial flower environments: one simulating a favourable environment with patches alternating high- and low-quality flowers (40% vs. 20% w/w sucrose solution), and the other a challenging environment with high-quality flowers alongside unrewarded ones (40% w/w sucrose solution vs. plain water). We hypothesised that bees would improve their foraging efficiency in both environments, but more rapidly in the more extreme one, where the greater reward difference creates stronger pressure to learn quickly. In both conditions, bees increased their sucrose intake per unit time over bouts. We also observed consistent differences in flower selectivity among individuals: in the favourable environment, bees that first visited high-quality flowers focused on them and avoided low-quality ones (became “picky”), while bees that first visited low-quality flowers kept visiting both types. Despite these differences, bees across environments and pickiness levels all reached similar sucrose intake rates by the third foraging bout, either by becoming more selective, collecting more sucrose solution, or reducing time spent foraging. These findings highlight the adaptability of bee foraging and suggest that early flower experiences may contribute to lasting individual differences in foraging behaviour. Significance statement Bumblebees are highly efficient pollinators of wild plants and commercial crops, yet their foraging behaviour varies notably among individuals. Understanding why bees differ in their foraging decisions is crucial, as it affects how they collect resources. We show that individual Bombus terrestris workers rapidly adapt to flower patches with different reward qualities. Remarkably, a bee’s first flower visits have lasting effects: individuals that started with high-quality flowers consistently favoured them and avoided low-quality ones, while those that started with low-quality flowers continued to visit both types over time. Despite these differences, bees reached similar nectar intake rates after just three foraging trips, regardless of how selective they were. Our findings show that bees can quickly adjust their foraging behaviour, and that early experiences play a key role in how they exploit resources across different environments.

Lau et al. use calcium imaging and statistical modeling to comprehensively survey reticulospinal activity during diverse locomotor behaviors. They find that a small set of functional modules act combinatorially to generate descending commands, and unexpectedly, this control architecture is stratified according to behavioral context.

What is the combined impact of individuals’ linguistic, economic, and gender backgrounds on their scientific productivity? This study uses a survey of 908 scientists to reveal that being a woman, a no...