Biology subjects

Solvi, C.

Publications and source records attributed to Solvi, C..

6 recordsLinked to original sources

bioRxiv2026

Relative reward memories retain multidimensional information in bumblebees

Previously, we showed that bumblebees encode reward value relative to local alternatives and, when comparing options learned in separate contexts, retrieve only their ordinal rank rather than absolute reward magnitude (Solvi et al., 2022). However, that study, like related work across species, varied reward along a single dimension. Natural rewards such as nectar are multidimensional, yet how such rewards are represented in relative memory remains unknown. We tested this by training bumblebees in separate contexts with rewards varying in two intrinsic dimensions, sucrose concentration and NaCl content, and then comparing options never encountered together. When only sucrose concentration varied, bees showed no preference between options that had each been locally better, despite differing in absolute concentration. With multidimensional rewards, however, this equivalence no longer held: bees preferred an option that had been locally better on both sucrose and NaCl over one better on only sucrose or only NaCl. A two-dimensional advantage also produced a stronger preference than a one-dimensional advantage 48 h after training. Thus, the ordinal rank we previously identified captures only part of the relative reward representation: with multidimensional rewards, bumblebees also retain information about the dimensions on which an option had been locally better.

animal behavior and cognition↗

bioRxiv2024

The Effect of Human Presence and Activity Type on Innovative Problem-Solving of Urban Eurasian Red Squirrels.

O_LIHumans impact wildlife positively and negatively, and increasing evidence shows that humans potentially play a major role in shaping cognition in wild animals. Recent evidence suggests, in particular, that the ability to innovate (an important cognitive ability for urban wildlife) can be affected by humans. However, the specific anthropogenic factors associated with shaping animal cognitive performance remain unclear. C_LIO_LIHere, across 15 urban areas in Oulu, Finland, we recorded 64 wild Eurasian red squirrels interactions with a novel puzzle box (innovative problem-solving) to obtain a highly preferred food, hazelnuts. C_LIO_LIWe then examined how different levels of human presence nearby, types of activity (walking, dog walking, cycling, and playground activities), and distance to the nearest footpaths influenced squirrels innovative problem-solving ability - measured as solving success at the population level and solving latency at the individual level. C_LIO_LIAt the population level, higher mean human presence nearby significantly decreased the proportion of squirrels that successfully solved the novel food-extraction problem ("innovators"), and greater human presence nearby decreased first-visit solving latency at individual level. Except for cycling, all types of human activities (walking, dog walking, and playground activity) significantly decreased first-visit success rate. Dog walking and playground activity had a greater negative impact on success rate at the population level than walking. Dog walking was the only outstanding factor affecting first-success latency. We also detected interaction effects between the types of human activities and nearest footpath on overall success rate of all innovators. C_LIO_LIThese results provide evidence for the negative effect of specific human-related factors on squirrels innovative problem-solving abilities. These factors may also exert selective pressure, potentially shaping the evolution of wildlife cognition. C_LI

animal behavior and cognition↗

bioRxiv2024

Does bumblebee preference of continuous over interrupted strings in string-pulling tasks indicate means-end comprehension?

Bumblebees (Bombus terrestris) have been shown to engage in string-pulling behavior to access rewards. The objective of this study was to elucidate whether bumblebees display means-end comprehension in a string-pulling task. We presented bumblebees with two options: one where a string is connected to an artificial flower containing a reward and the other presenting an interrupted string. Bumblebees displayed a consistent preference for pulling connected strings over interrupted ones after training with a stepwise pulling technique. When exposed to novel string colors, bees continued to exhibit a bias towards pulling the connected string. This suggests that bumblebees engage in featural generalization of the visual display of the string connected to the flower in this task. If the view of the string connected to the flower was restricted during the training phase, the proportion of bumblebees choosing the connected strings significantly decreased. Similarly, when the bumblebees were confronted with coiled connected strings during the testing phase, they failed to identify and reject the interrupted strings. This finding underscores the significance of visual consistency in enabling the bumblebees to perform the task successfully. Our results suggest that bumblebees ability to distinguish between continuous strings and interrupted strings relies on a combination of image matching and associative learning, rather than means-end understanding. These insights contribute to a deeper understanding of the cognitive processes employed by bumblebees when tackling complex spatial tasks.

ecology↗

bioRxiv2024

Noxious stimulation induces self-protective behaviour in bumblebees

Self-grooming directed towards a noxiously-stimulated body part is one indicator that an animal may feel pain. In insects, the lack of evidence for such behaviour has been widely argued to reflect the absence of pain experiences. Here, we tested whether bumblebees (Bombus terrestris) selectively groom one of their antennae that was touched with a noxiously-heated (65 {square}C) probe. In the first two minutes after being touched with the noxiously-heated probe, bees groomed their touched antenna a) more than their untouched antenna, b) more than bees that were touched on the antenna with an unheated probe, and c) more than control (untouched) bees groomed either of their antennae. Our results clearly show that bumblebees can direct grooming towards a site of noxious stimulation. Our findings thus refute arguments that claim that insects do not feel pain because of their lack of displaying this behaviour.

animal behavior and cognition↗

bioRxiv2022

Bumblebees retrieve only the ordinal ranking of foraging options when comparing memories obtained in distinct settings

Are animals preferences determined by absolute memories for options (e.g., reward sizes) or by their remembered ranking (better/worse)? The only studies examining this question suggest humans and starlings utilize memories for both absolute and relative information. We show that bumblebees make decisions using only memories of ordinal comparisons. After learning to discriminate pairs of different flowers by sucrose concentration, bumblebees preferred flowers (in novel pairings) with 1) higher ranking over equal absolute reward, 2) higher ranking over higher absolute reward, and 3) identical qualitative ranking but different quantitative ranking equally. Despite these suboptimal choices, bumblebees found the optimal option in an ecologically relevant foraging task. Our results illuminate a divergent mechanism of learned preferences that may have arisen from adaptations to bumblebees natural environment.

animal behavior and cognition↗

bioRxiv2020

Bumblebees learn a relational rule but switch to a win-stay/lose-switch heuristic after extensive training

Mapping animal performance in a behavioural task to underlying cognitive mechanisms and strategies is rarely straightforward, since a task may be solvable in more than one manner. Here, we show that bumblebees perform well on a concept-based visual discrimination task, but spontaneously switch from a concept-based solution to a simpler heuristic with extended training, all while continually increasing performance. Bumblebees were trained in an arena to find reward on displays with shapes of different sizes where they could not use low-level visual cues. One group of bees was rewarded at displays with bigger shapes and another group at displays with smaller shapes. Analysis of total choices shows bees increased their performance over 30 bouts to above chance. However, analyses of first and sequential choices suggest that after approximately 20 bouts, bumblebees changed to a win-stay/lose-switch strategy. Comparing bees behaviour to a probabilistic model based on a win-stay/lose-switch strategy further supports the idea that bees changed strategies with extensive training. Analyses of unrewarded tests indicate bumblebees learned and retained the concept of relative size even after they had already switched to a win-stay, lost-shift strategy. We propose that the reason for this strategy switching may be due to cognitive flexibility and efficiency.

animal behavior and cognition↗