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Langridge KV, Wilke C, Riabinina O, Vorobyev M, Hempel de Ibarra N. Approach Direction Prior to Landing Explains Patterns of Colour Learning in Bees. Front Physiol 2021; 12:697886. [PMID: 34955870 PMCID: PMC8692860 DOI: 10.3389/fphys.2021.697886] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Accepted: 11/02/2021] [Indexed: 11/18/2022] Open
Abstract
Gaze direction is closely coupled with body movement in insects and other animals. If movement patterns interfere with the acquisition of visual information, insects can actively adjust them to seek relevant cues. Alternatively, where multiple visual cues are available, an insect's movements may influence how it perceives a scene. We show that the way a foraging bumblebee approaches a floral pattern could determine what it learns about the pattern. When trained to vertical bicoloured patterns, bumblebees consistently approached from below centre in order to land in the centre of the target where the reward was located. In subsequent tests, the bees preferred the colour of the lower half of the pattern that they predominantly faced during the approach and landing sequence. A predicted change of learning outcomes occurred when the contrast line was moved up or down off-centre: learned preferences again reflected relative frontal exposure to each colour during the approach, independent of the overall ratio of colours. This mechanism may underpin learning strategies in both simple and complex visual discriminations, highlighting that morphology and action patterns determines how animals solve sensory learning tasks. The deterministic effect of movement on visual learning may have substantially influenced the evolution of floral signals, particularly where plants depend on fine-scaled movements of pollinators on flowers.
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Affiliation(s)
- Keri V. Langridge
- Department of Psychology, Centre for Research in Animal Behaviour, University of Exeter, Exeter, United Kingdom
| | - Claudia Wilke
- Department of Psychology, Centre for Research in Animal Behaviour, University of Exeter, Exeter, United Kingdom
- Department of Psychology, University of York, York, United Kingdom
| | - Olena Riabinina
- Department of Biosciences, Durham University, Durham, United Kingdom
| | - Misha Vorobyev
- School of Optometry and Vision Science, University of Auckland, Auckland, New Zealand
| | - Natalie Hempel de Ibarra
- Department of Psychology, Centre for Research in Animal Behaviour, University of Exeter, Exeter, United Kingdom
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Nityananda V, Chittka L. Different effects of reward value and saliency during bumblebee visual search for multiple rewarding targets. Anim Cogn 2021; 24:803-814. [PMID: 33515306 PMCID: PMC8238720 DOI: 10.1007/s10071-021-01479-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Revised: 01/11/2021] [Accepted: 01/13/2021] [Indexed: 11/18/2022]
Abstract
Several animals, including bees, use visual search to distinguish targets of interest and ignore distractors. While bee flower choice is well studied, we know relatively little about how they choose between multiple rewarding flowers in complex floral environments. Two factors that could influence bee visual search for multiple flowers are the saliency (colour contrast against the background) and the reward value of flowers. We here investigated how these two different factors contribute to bee visual search. We trained bees to independently recognize two rewarding flower types that, in different experiments, differed in either saliency, reward value or both. We then measured their choices and attention to these flowers in the presence of distractors in a test without reinforcement. We found that bees preferred more salient or higher rewarding flowers and ignored distractors. When the high-reward flowers were less salient than the low-reward flowers, bees were nonetheless equally likely to choose high-reward flowers, for the reward and saliency values we used. Bees were also more likely to attend to these high-reward flowers, spending higher inspection times around them and exhibiting faster search times when choosing them. When flowers differed in reward, we also found an effect of the training order with low-reward targets being more likely to be chosen if they had been encountered during the more immediate training session prior to the test. Our results parallel recent findings from humans demonstrating that reward value can attract attention even when targets are less salient and irrelevant to the current task.
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Affiliation(s)
- Vivek Nityananda
- Biosciences Institute, Newcastle University, Henry Wellcome Building, Framlington Place, Newcastle Upon Tyne, NE2 4HH, UK. .,School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, Mile End, London, E1 4NS, UK.
| | - Lars Chittka
- School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, Mile End, London, E1 4NS, UK
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3
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Lihoreau M, Ings TC, Chittka L, Reynolds AM. Signatures of a globally optimal searching strategy in the three-dimensional foraging flights of bumblebees. Sci Rep 2016; 6:30401. [PMID: 27459948 PMCID: PMC4961967 DOI: 10.1038/srep30401] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2015] [Accepted: 07/01/2016] [Indexed: 11/09/2022] Open
Abstract
Simulated annealing is a powerful stochastic search algorithm for locating a global maximum that is hidden among many poorer local maxima in a search space. It is frequently implemented in computers working on complex optimization problems but until now has not been directly observed in nature as a searching strategy adopted by foraging animals. We analysed high-speed video recordings of the three-dimensional searching flights of bumblebees (Bombus terrestris) made in the presence of large or small artificial flowers within a 0.5 m3 enclosed arena. Analyses of the three-dimensional flight patterns in both conditions reveal signatures of simulated annealing searches. After leaving a flower, bees tend to scan back-and forth past that flower before making prospecting flights (loops), whose length increases over time. The search pattern becomes gradually more expansive and culminates when another rewarding flower is found. Bees then scan back and forth in the vicinity of the newly discovered flower and the process repeats. This looping search pattern, in which flight step lengths are typically power-law distributed, provides a relatively simple yet highly efficient strategy for pollinators such as bees to find best quality resources in complex environments made of multiple ephemeral feeding sites with nutritionally variable rewards.
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Affiliation(s)
- Mathieu Lihoreau
- Department of Biological and Experimental Psychology, School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London E1 4NS, UK
| | - Thomas C Ings
- Department of Biological and Experimental Psychology, School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London E1 4NS, UK
| | - Lars Chittka
- Department of Biological and Experimental Psychology, School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London E1 4NS, UK
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Fisogni A, Rossi M, Sgolastra F, Bortolotti L, Bogo G, de Manincor N, Quaranta M, Galloni M. Seasonal and annual variations in the pollination efficiency of a pollinator community of Dictamnus albus L. PLANT BIOLOGY (STUTTGART, GERMANY) 2016; 18:445-454. [PMID: 26573095 DOI: 10.1111/plb.12417] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Accepted: 11/11/2015] [Indexed: 06/05/2023]
Abstract
The interplay between insect and plant traits outlines the patterns of pollen transfer and the subsequent plant reproductive fitness. We studied the factors that affect the pollination efficiency of a pollinator community of Dictamnus albus L. by evaluating insect behaviour and morphological characteristics in relation to flowering phenology. In order to extrapolate the pollinator importance of single taxa and of the whole pollinator guild, we calculated an index distinguishing between potential (PPI) and realized (RPI) pollinator importance. Although the pollinator species spectrum appeared rather constant, we found high intra- and inter-annual variability of pollinator frequency and importance within the insect community. Flower visitation rate strictly depended on insect abundance and on the overlap between their flying period and flower blooming. All the pollinators visited flowers from the bottom to the top of the racemes, excluding intra-plant geitonogamous pollination, and most of them showed high pollen fidelity. Only medium large-sized bees could contact the upward bending stiles while feeding on nectar, highlighting a specialisation of the plant towards bigger pollinators. Moreover, we found evidence of functional specialisation, since all pollinators were restricted to a single taxonomic group (order: Hymenoptera; superfamily: Apoidea). Both the PPI and RPI indices indicate Habropoda tarsata as the most important pollinator of D. albus. Following hand cross-pollination experiments we revealed the presence of pollination limitation in 1 of the 3 years of field study. We discuss this result in relation to flowering abundance and to possible mismatches of phenological periods between plants and insects.
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Affiliation(s)
- A Fisogni
- Dipartimento di Scienze Biologiche, Geologiche e Ambientali, Università di Bologna, Bologna, Italy
| | - M Rossi
- Istituto di Bioscienze e Biorisorse, Consiglio Nazionale delle Ricerche, Portici (NA), Italy
| | - F Sgolastra
- Dipartimento di Scienze Agrarie, Università di Bologna, Bologna, Italy
| | - L Bortolotti
- Consiglio per la Ricerca in Agricoltura e l'Analisi dell'Economia Agraria - Unità di Ricerca di Apicoltura e Bachicoltura (CRA-API), Bologna, Italy
| | - G Bogo
- Dipartimento di Scienze Biologiche, Geologiche e Ambientali, Università di Bologna, Bologna, Italy
- Consiglio per la Ricerca in Agricoltura e l'Analisi dell'Economia Agraria - Unità di Ricerca di Apicoltura e Bachicoltura (CRA-API), Bologna, Italy
| | - N de Manincor
- Dipartimento di Scienze Biologiche, Geologiche e Ambientali, Università di Bologna, Bologna, Italy
| | - M Quaranta
- Consiglio per la Ricerca in Agricoltura e l'Analisi dell'Economia Agraria - Centro di Ricerca per l'Agrobiologia e la Pedologia (CRA-ABP), Florence, Italy
| | - M Galloni
- Dipartimento di Scienze Biologiche, Geologiche e Ambientali, Università di Bologna, Bologna, Italy
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Morawetz L, Chittka L, Spaethe J. Strategies of the honeybee Apis mellifera during visual search for vertical targets presented at various heights: a role for spatial attention? F1000Res 2014; 3:174. [PMID: 25254109 PMCID: PMC4168805 DOI: 10.12688/f1000research.4799.1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 07/22/2014] [Indexed: 11/28/2022] Open
Abstract
When honeybees are presented with a colour discrimination task, they tend to choose swiftly and accurately when objects are presented in the ventral part of their frontal visual field. In contrast, poor performance is observed when objects appear in the dorsal part. Here we investigate if this asymmetry is caused by fixed search patterns or if bees can use alternative search mechanisms such as spatial attention, which allows flexible focusing on different areas of the visual field. We asked individual honeybees to choose an orange rewarded target among blue distractors. Target and distractors were presented in the ventral visual field, the dorsal field or both. Bees presented with targets in the ventral visual field consistently had the highest search efficiency, with rapid decisions, high accuracy and direct flight paths. In contrast, search performance for dorsally located targets was inaccurate and slow at the beginning of the test phase, but bees increased their search performance significantly after a few learning trials: they found the target faster, made fewer errors and flew in a straight line towards the target. However, bees needed thrice as long to improve the search for a dorsally located target when the target’s position changed randomly between the ventral and the dorsal visual field. We propose that honeybees form expectations of the location of the target’s appearance and adapt their search strategy accordingly. Different possible mechanisms of this behavioural adaptation are discussed.
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Affiliation(s)
- Linde Morawetz
- Department of Integrative Zoology, University of Vienna, Vienna, 1090, Austria ; Behavioral Physiology and Sociobiology, Biozentrum, University of Würzburg, Würzburg, 97074, Germany
| | - Lars Chittka
- Biological and Experimental Psychology, School of Biological and Chemical Sciences, Queen Mary University of London, London, E1 4NS, UK
| | - Johannes Spaethe
- Behavioral Physiology and Sociobiology, Biozentrum, University of Würzburg, Würzburg, 97074, Germany
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