Prof. Dr. Martin Giurfa
 
 new address:

  
 Centre de Recherches sur la Cognition Animale
 CNRS - Université Paul Sabatier-Toulouse III
 118 Route de Narbonne
 31062 Toulouse cedex 4
 FRANCE
 
phone:  0033 561 55 67 33
fax:    0033 561 55 61 54
e-mail: giurfa@cict.fr
 

 

 

 

1) Detection and recognition of coloured stimuli by honeybees (funded by the German Research Council – DFG Me-Giu 365/20-2)

The purpose of this project is to study how spectral parameters affect the detection of colour stimuli by free-flying honeybees. We have established the minimal visual angle that a spectral stimulus should subtend in order to be detected, and determined that bees make use of their colour vision system as well as a green-receptor based achromatic system for the detection of coloured targets. The minimum visual angle required for detection of a coloured stimulus is 15° if the stimulus presents chromatic contrast but no green contrast, whilst it is 5° if it presents both kinds of contrast. Both systems are alternatively used depending on the visual angle subtended by the targets at the bee’s eye: at larger visual angles (>15°) bees use the chromatic properties of the targets; at smaller ones (ca. 5°) they use the achromatic green contrast. Our results enable to relate detection capabilities of Hymenoptera with different signalling strategies of flowers and also to characterize the neural elements involved in such a task. These studies are performed in collaboration with Dr. M. Vorobyev and Natalie Hempel de Ibarra.

 

 

2) Symmetry perception in honeybees: abstraction and concept formation in simple nervous systems (funded by the German Research Council – DFG Giu 291/3-1)

The purpose of this project is to examine a honeybee's capability to develop a concept of bilateral symmetry. We showed that bees may be trained to discriminate bilaterally symmetric from non-symmetric patterns and that they can transfer the task accordingly to novel stimuli. This demonstrates a perceptual capacity to detect symmetric vs. asymmetric patterns and raises the question of whether bees can categorise patterns according to their symmetric or asymmetric outline. The question of whether organisms with relatively simple nervous systems can abstract rules related to the problem of symmetry recognition from multiple learning sets is relevant since it relates not only to the level of perception but also to that of their cognitive abilities. These studies were performed in collaboration with Nina Müller-Deisig.

 

 

3) The Importance of Mushroom bodies for Higher-order Multimodal Computations in Insects (funded by the German Research Council – SFB 515 – Project C7 and by Procope 2000 – Cooperation with INRA, Paris, France)

The mushroom bodies (MB) constitute the most obvious and voluminous structures in the insect brain. Each MB consists of two fused symmetrical substructures of about 170,000 tightly packed neurones, the Kenyon cells. Such neurones receive their input in the calyx region and project two collaterals to the a- and b-lobe, the output regions of the MB. The calyx region is subdivided into 3 major input areas (lip, collar and basal ring) that receive input from different sensory pathways: olfactory projection neurones connecting the antennal lobe with the mushroom bodies project to the lip but not to the collar whereas visual projection neurones from the medulla and the lobula project to the collar exclusively. Such a compartmentalisation of the MB inputs suggests separated processing of visual and olfactory signals. Since MB output neurones are clearly multimodal, integration of these signals should also occur at the MB level.

The objective of our research program is to analyse the functional role of the insect MBs. To that aim we combine training procedures in different learning contexts with selective MB ablation by means of application of hydroxyurea at the early larval stage. Such an ablation technique has been already established in our laboratory by Dr. Dagmar Malun. It allows to test specifically whether MB-ablated bees are capable of performing certain tasks pertaining to different learning contexts as well as intact bees do. Particularly, we raise the question of whether the MBs provide a neuronal substrate for higher-order multimodal computations and context-based, configural associations. Patterning experiments with intact and ablated bees are performed to answer this question (see Nina Müller Deisig and Bernhard Komischke).

 

Methods and Interests

Our work is mainly based on behavioural and psychophysical methods. Behavioural experiments with bees are performed to determine learning and discrimination capabilities. Different set ups where the behaviour of the bees is carefully controlled and recorded are used to that aim. The psychophysical approach allows to propose specific models on the visual processing and to test them in appropriate behavioural experiments.

 

Selected Publications

[1] Giurfa M, Núñez J, Backhaus W (1994) Odour and colour information in the foraging choice behaviour of the honeybee. Journal of Comparative Physiology A 175:773-779.

[2] Giurfa M, Backhaus W, Menzel R (1995) Color and angular orientation in the discrimination of bilateral symmetric patterns in the honeybee. Naturwissenschaften 82:198-201.

[3] Giurfa M, Núñez J, Chittka L, Menzel R (1995) Colour preferences in flower-naive honeybee foragers. Journal of Comparative Physiology A 177:247-259.

[4] Giurfa M, Vorobyev M, Kevan P, Menzel R (1996) Detection of coloured stimuli by honeybees: minimum visual angles and receptor specific contrasts. Journal of Comparative Physiology A 178:699-709

[5] Giurfa M, Eichmann B, Menzel R (1996) Symmetry perception in an insect. Nature 382:458-461.

[6] Giurfa M (1996) Movement patterns of honeybee foragers: motivation and decision rules dependent on the rate of reward. Behaviour 133:579-596

[7] Giurfa M, Vorobyev M, Brandt R, Posner B, Menzel R (1997) Detection and discrimination of coloured stimuli by honeybees: alternative use of achromatic and chromatic signals. Journal of Comparative Physiology A 180:235-244.

[8] Giurfa M, Menzel R (1997) Insect visual perception: complex abilities by simple nervous systems. Current Opinion in Neurobiology 7:505-513.

[9] Giurfa M, Vorobyev M (1998) The angular range of achromatic target detection by honeybees. Journal of Comparative Physiology A 183:101-110.

[10] Giurfa M, Hammer M, Stach S, Stollhoff N, Müller-Deisig N, Mizyrycki C (1998) Pattern learning by honeybees: conditioning procedure and recognition strategy. Animal Behaviour 57:315-324.

[11] Giurfa M, Capaldi E (1999) Vectors, routes and maps: new discoveries about navigation in insects. Trends in Neurosciences 22:237-242.

[12] Menzel R, Giurfa M (1999) Cognition by a mini brain. Nature 400:718-719.

[13] Giurfa M, Dafni A, Neal PR (1999) Floral symmetry and its role in plant pollinator systems. International Journal of Plant Sciences 160:541-550.

[14] Giurfa, M, Zaccardi G, Vorobyev M (1999) How do bees detect coloured targets using different regions of their compound eyes. Journal of Comparative Physiology A 185:591-600.

 

 Complete List of Publications

 

last update: 28 Jan 2003