Biology subjects

Procenko, O.

Publications and source records attributed to Procenko, O..

4 recordsLinked to original sources

bioRxiv2025

Acute stress modulates early visual perception and decision-making speed in bees without compromising accuracy

Acute stress is known to influence decision-making, but it can also directly affect earlier stages of sensory processing. In humans, stress alters the perception of basic visual features, fine-tuning vision to support faster responses in threatening contexts. Whether stress induces similar changes in early vision in insects and thus affects visually guided decision-making, remains unknown. Here, we examined how acute stress, simulated via vigorous shaking resembling a predatory attack, affects bumblebees sensitivity thresholds for resolution and contrast sensitivity, two basic visual features, as well as their choice behaviour and decision speed in a dual-choice discrimination task. We found that, similar to humans, stress modulated both thresholds. It increased contrast sensitivity thresholds and shifted spatial frequency thresholds toward finer resolution as well as affecting bee final choice behaviour. Not only were stressed bees more likely to commit to a choice, but they did so significantly faster when their early perceptual decisions were accurate. Collectively, our results suggest that stress reshapes bee visual sensitivity and decision-making not only through an increase in reactivity, but with a flexible shift in decision-making driven by perceptual confidence.

animal behavior and cognition↗

bioRxiv2025

Bumblebee string-pulling skill spreads between colonies under open diffusion conditions

Socially-transmitted behavioural traits can, if they persist in a group of animals over time, give rise to locally-adapted phenotypes that can enhance survival. This capacity is widespread through the animal kingdom, and forms the foundation of cultural inheritance. While social learning is well-documented among insects, and particularly in social insects such as bumblebees, the extent to which such behaviours can spread beyond initial kin groups and persist over time remains largely unknown. String-pulling is a non-natural foraging behaviour where bees must manipulate a string to extract an out-of-reach artificial flower and collect a reward, and has previously shown to spread via social learning. However, this was demonstrated only in highly controlled paired-dyad settings, where interactions between bees were strictly limited. Here, we show that string-pulling can spread both within and between bumblebee colonies and persist over time, under previously-untested open diffusion conditions. These are of greater ecological validity compared with classical paired dyad paradigms, and involve the seeding of a manually-trained demonstrator into a group of naive conspecifics. From this single point of origin, string-pulling behaviour spread rapidly within original, primary colonies. Once the behaviour was established in the primary colonies, secondary colonies were introduced, and string-pulling was also acquired by these new foragers. Furthermore, string-pulling was acquired through individual trial-and-error learning by a small number of bees in control colonies, which lacked trained demonstrators. These results confirm and build upon previous findings in bumblebees, and contribute to a growing body of evidence suggesting that social learning enables animals to establish local behavioural adaptations in the absence of the computational power provided by large brains.

animal behavior and cognition↗

bioRxiv2023

Physically stressed bees expect less reward in an active choice judgement bias test

Emotion-like states in animals are commonly assessed using judgment bias tests, which measure responses to ambiguous information. A few studies have recently used these tests to argue for the presence of emotion-like states in insects. However, the results from most of these studies could have other explanations, including changes in motivation and attention. To control for these explanations, we therefore developed a novel judgment bias test, requiring bumblebees to make an active choice indicating their interpretation of ambiguous stimuli. Bumblebees were trained to associate high or low rewards, delivered in two different reward chambers, with distinct colors. Two groups of bees were then physically stressed by shaking or trapping, while the third group served as a control. We subsequently presented the bees with ambiguous colors between the two learnt colors and noted which reward chamber they chose. When presented with ambiguous colors, stressed bees were less likely than control bees to enter the reward chamber previously associated with high reward. We modelled bee behavior using signal detection and drift diffusion models and showed that control bees and stressed bees were, respectively, more likely to respond optimistically and pessimistically to ambiguous cues. The signal detection model further showed that the behavior of stressed bees was explained by a reduction in their prior expectation of high rewards. Our findings thus provide strong evidence for emotion-like states in bees and suggest that their stress-induced pessimistic behavior is explained by a reduced expectation of higher rewards.

animal behavior and cognition↗

bioRxiv2022

The establishment and transmission of novel foraging techniques indicates a capacity for culture in bumblebees (Bombus terrestris).

The astonishing behavioural repertoires of social insects have been thought largely innate, but these insects have repeatedly demonstrated remarkable capacities for both individual and social learning. Using the bumblebee Bombus terrestris as a model, we developed a two-option puzzle box task and used open diffusion paradigms to observe the transmission of novel, non-natural foraging behaviours through populations. Box-opening behaviour spread through colonies seeded with a demonstrator trained to perform one of the two possible behavioural variants, and the observers acquired the demonstrated variant. This preference persisted among observers even when the alternative technique was discovered. In control diffusion experiments that lacked a demonstrator, some bees spontaneously opened the puzzle boxes but were significantly less proficient than those that learned in the presence of a demonstrator. This suggested that social learning was crucial to proper acquisition of box-opening. Additional open diffusion experiments where two behavioural variants were initially present in similar proportions ended with a single variant becoming dominant, due to stochastic processes. This could lead to the emergence and maintenance of local cultural variation. These results suggest that bumblebees, like mammals and birds, may have the capacity for culture and to sustain cultural variation.

animal behavior and cognition↗