Levente L Orbán
School of Psychology,
University of Ottawa
Ottawa, Ont., K1R 6N5
Bee lab, Quantitative Investigation of Brain and Behavior Group
- Comparative cognition
- Computational models of cognition
- Unlearned pattern preferences
- Unsupervised artificial neural network models
- Orbán LL, Plowright CMS (2013) The effect of flower-like and flower-unlike visual properties on choice of unrewarding patterns by bumblebees details
download from publisher
Abstract How do distinct visual stimuli help bumblebees discover flowers before they have experienced any reward outside of their nest? Two visual floral properties, type of a pattern (concentric vs radial) and its position on unrewarding artificial flowers (central vs peripheral on corolla) were manipulated in two experiments. Both visual properties showed significant effects on floral choice. When pitted against each other, pattern was more important than position. Experiment 1 shows a significant effect of concentric pattern position, and Experiment 2 shows a significant preference towards radial patterns regardless of their position. These results show that the presence of markings at the center of a flower are not so important as the presence of markings that will direct bees there.
E! Science News,
uOttawa Experts Blog
- Orbán LL, Chartier S (2013) Unsupervised non-linear neural networks capture aspects of floral choice behaviour
European Symposium on Artificial Neural Networks, Computational Intelligence and Machine Learning
download free from publisher | pdf
Abstract Two unsupervised neural networks were tested to understand the extent to which they capture elements of bumblebees’ unlearned preferences towards flower-like visual properties. The networks, which are based on Independent Component Analysis and Feature-Extracting Bidirectional Associative Memory use images of test-patterns that are identical to ones used in behavioural studies. While both models show consistency with behavioural results, the ICA model matches behavioural results substantially better in terms of image reconstruction quality of radial and concentric patterns, and foliage background. Both models generated a novel prediction of an interaction between spatial frequency and symmetry. These results are interpreted to support the hypothesis that flower displays are adapted to pollinators’ information processing constraints.
- Orbán LL, Plowright CMS and Plowright RC (2012) The effect of feeder location on pollen collection by bumble bees in a tomato greenhouse in Ontario, Canada details
Journal of Economic Entomology
download from publisher | pdf
Abstract The foraging behavior of bumble bees (Bombus impatiens Cresson) was examined as a function of feeder location containing sugar solution in a commercial tomato greenhouse in Manotick, Ontario, Canada. The feeders were located within the nest-box (fed-close) or placed 1.5 m away (fed-far) and the placement of the two types of colonies was counterbalanced over time. No effect of feeder location was found in colony activity levels or in pollen load size. A foraging trade-off between sugar solution and pollen collection, however, was found: the proportion of foraging trips in which pollen was brought back was signiÞcantly reduced for fed-far colonies, which contrasts with our laboratory study in which the opposite effect was found. We interpret our Þndings as possibly reßecting a limitation in pollen supply in the greenhouse: an already possibly strained ability to Þnd and bring back pollen to the colony was accentuated by increasing the task demands of collecting sugar solution.
- Orbán LL and Dastur FN (2012) Shifts in color discrimination during early pregnancy details
download from publisher | pdf | stats
Abstract The present study explores two hypotheses: a) women during early pregnancy should experience increased color discrimination ability, and b) women during early pregnancy should experience shifts in subjective preference away from images of foods that appear either unripe or spoiled. Both of these hypotheses derive from an adaptive view of pregnancy sickness that proposes the function of pregnancy sickness is to decrease the likelihood of ingestion of foods with toxins or teratogens. Changes to color discrimination could be part of a network of perceptual and physiological defenses (e.g., changes to olfaction, nausea, vomiting) that support such a function. Participants included 13 pregnant women and 18 non-pregnant women. Pregnant women scored significantly higher than non-pregnant controls on the Farnsworth-Munsell (FM) 100 Hue Test, an objective test of color discrimination, although no difference was found between groups in preferences for food images at different stages of ripeness or spoilage. These results are the first indication that changes to color discrimination may occur during early pregnancy, and is consistent with the view that pregnancy sickness may function as an adaptive defense mechanism.