| 1. |
- Balkenius, Anna, et al.
(författare)
-
A model of selecion between stimulus and place strategy in a hawkmoth
- 2004
-
Ingår i: Adaptive Behavior. - : SAGE Publications. - 1741-2633 .- 1059-7123. ; 12:1, s. 21-35
-
Tidskriftsartikel (refereegranskat)abstract
- In behavioral experiments, the hawkmoth Deilephila elpenor can learn both the color and the position of artificial flowers. When very similar colors are used, moths select the correct color during the first test on a given day, thus using a stimulus strategy, but after repeated rewards, they switch to a place strategy and choose the flower in the position where they received the reward. When dissimilar colors are used, the moths continue to select flowers based on color and ignore position. We show how a computational model can reproduce the behavior in the experimental situation. The aim of the model is to investigate which learning and behavior selection strategies are necessary to reproduce the behavior observed in the experiment. The model is based on behavioral data and the sensitivities of the moth photoreceptors. The model consists of a number of interacting behavior systems that are triggered by specific stimuli and control specific behaviors. The ability of the moth to learn the colors of different flowers and the adaptive processes involved in the choice between stimulus-approach and place-approach strategies are reproduced very accurately by the model. The model has implications both for further studies of the ecology of the animal and for robotic systems.
|
|
| 2. |
- Balkenius, Anna, et al.
(författare)
-
Colour constancy in diurnal and nocturnal hawkmoths
- 2004
-
Ingår i: Journal of Experimental Biology. - : The Company of Biologists. - 1477-9145 .- 0022-0949. ; 207:19, s. 3307-3316
-
Tidskriftsartikel (refereegranskat)abstract
- Diurnal and nocturnal hawkmoths have been shown to use colour vision for flower discrimination. Here, we present evidence that the nocturnal hawkmoth Deilephila elpenor and the diurnal hawkmoth Macroglossum stellatarum also have colour constancy. Colour constancy was shown in D. elpenor in two multiple-choice experiments with five different bluish colour patches under white and blue illumination and with five yellowish colour patches under white, blue and yellow illumination. The mechanism underlying colour constancy in both species was investigated in two dual-choice experiments. The choice behaviour is consistent with the use of the von Kries coefficient law. Although the moths have colour constancy, they react to the colour of the illumination. They make fewer choices when tested under the changed illumination, where they never receive a reward, compared with the training illumination. Even if colour constancy can be explained by a von Kries adaptation mechanism, the fact that the animals discriminate between different illuminations indicates that some additional process must be involved.
|
|
| 3. |
- Balkenius, Anna, et al.
(författare)
-
Colour preferences influences odour learning in the hawkmoth, Macroglossum stellatarum
- 2006
-
Ingår i: Naturwissenschaften. - : Springer Science and Business Media LLC. - 1432-1904 .- 0028-1042. ; 93:5, s. 255-258
-
Tidskriftsartikel (refereegranskat)abstract
- The hummingbird hawkmoth, Macroglossum stellatarum, learns colour fast and reliably. It has earlier been shown to spontaneously feed from odourless artificial flowers. Now, we have studied odour learning. The moths were trained to discriminate feeders of the same colour but marked with different odours. They did not learn to discriminate two natural flower odours when they were presented with the innately preferred colour blue, but they did learn this discrimination combined with yellow or green colours that are less attractive to the moth. The yellow colour could be trained to become as attractive as the innately preferred blue colour and the blue colour could be trained to become less attractive. This is the first proof of odour learning in a diurnal moth. The results show that M. stellatarum can use more than one modality in their foraging behaviour and that the system is plastic. By manipulating the preferences for the different colours, their influence on odour learning could be changed.
|
|
| 4. |
- Balkenius, Anna, et al.
(författare)
-
How do Hawkmoths Learn Multi-Modal Stimuli? A Comparison of Three Models
- 2008
-
Ingår i: Adaptive Behavior. - : SAGE Publications. - 1741-2633 .- 1059-7123. ; 16:6, s. 349-360
-
Tidskriftsartikel (refereegranskat)abstract
- The moth Macroglossum stellatarum can learn the color and sometimes the odor of a rewarding food source. We present data from 20 different experiments with different combinations of blue and yellow artificial flowers and the two odors, honeysuckle and lavender. The experiments show that learning about the odors depends on the color used. By training on different color—odor combinations and testing on others, it becomes possible to investigate the exact relation between the two modalities during learning. Three computational models were tested in the same experimental situations as the real moths and their predictions were compared with the experimental data. The average error over all experiments as well as the largest deviation from the experimental data were calculated. Neither the Rescorla—Wagner model nor a learning model with independent learning for each stimulus component were able to explain the experimental data. We present the new hawkmoth learning model, which assumes that the moth learns a template for the sensory attributes of the rewarding stimulus. This model produces behavior that closely matches that of the real moth in all 20 experiments.
|
|
| 5. |
|
|
| 6. |
|
|
| 7. |
- Balkenius, Anna, et al.
(författare)
-
The relative importance of olfaction and vision in a diurnal and a nocturnal hawkmoth
- 2006
-
Ingår i: Journal of Comparative Physiology A. - : Springer Science and Business Media LLC. - 1432-1351 .- 0340-7594. ; 192:4, s. 431-437
-
Tidskriftsartikel (refereegranskat)abstract
- Nectar-feeding animals can use vision and olfaction to find rewarding flowers and different species may give different weight, to the two sensory modalities. We have studied how a diurnal or nocturnal lifestyle affects the weight given to vision and olfaction. We tested naive hawkmoths of two species in a wind tunnel, presenting an odour source and a visual stimulus. Although the two species belong to the same subfamily of sphingids, the Macroglossinae, their behaviour was quite different. The nocturnal Deilephila elpenor responded preferably to the odour while the diurnal Macroglossum stellatarum strongly favoured the visual stimulus. Since a nocturnal lifestyle is ancestral for sphingids, the diurnal species, M. stellatarum, has evolved from nocturnal moths that primarily used olfaction. During bright daylight visual cues may have became more important than odour.
|
|
| 8. |
- Beckmann, Holger, et al.
(författare)
-
Spectral sensitivity in Onychophora (velvet worms) revealed by electroretinograms, phototactic behaviour and opsin gene expression.
- 2015
-
Ingår i: Journal of Experimental Biology. - : The Company of Biologists. - 1477-9145 .- 0022-0949. ; 218:6, s. 915-922
-
Tidskriftsartikel (refereegranskat)abstract
- Onychophorans typically possess a pair of simple eyes, inherited from the last common ancestor of Panarthropoda (Onychophora + Tardigrada + Arthropoda). These visual organs are thought to be homologous to the arthropod median ocelli, whereas the compound eyes most likely evolved in the arthropod lineage. To gain insights into the ancestral function and evolution of the visual system in panarthropods, we investigated phototactic behaviour, opsin gene expression and the spectral sensitivity of the eyes in two representative species of Onychophora: Euperipatoides rowelli (Peripatopsidae), and Principapillatus hitoyensis (Peripatidae). Our behavioural analyses, in conjunction with previous data, demonstrate that both species exhibit photonegative responses to wavelengths ranging from ultraviolet to green light (370-530 nm), while electroretinograms reveal that the onychophoran eye is maximally sensitive to blue light (peak sensitivity ~480 nm). Template fits to the obtained sensitivities suggest that the onychophoran eye is monochromatic. To clarify on which type of opsin the single visual pigment is based, we localised the corresponding mRNA in the onychophoran eye and brain using in situ hybridization. Our data show that the r-opsin gene (onychopsin) is expressed exclusively in the photoreceptor cells of the eye, whereas the c-opsin mRNA is confined to optic ganglion cells and the brain. Together, our findings suggest that the onychopsin is involved in vision, whereas the c-opsin might have a photoreceptive, non-visual function in onychophorans.
|
|
| 9. |
- Bergman, Martin, et al.
(författare)
-
Seeing the world through the eyes of a butterfly : visual ecology of the territorial males of Pararge aegeria (Lepidoptera: Nymphalidae)
- 2021
-
Ingår i: Journal of Comparative Physiology A: Neuroethology, Sensory, Neural, and Behavioral Physiology. - : Springer Science and Business Media LLC. - 0340-7594. ; 207:6, s. 701-713
-
Tidskriftsartikel (refereegranskat)abstract
- Combining studies of animal visual systems with exact imaging of their visual environment can get us a step closer to understand how animals see their “Umwelt”. Here, we have combined both methods to better understand how males of the speckled wood butterfly, Pararge aegeria, see the surroundings of their perches. These males are well known to sit and wait for a chance to mate with a passing females, in sunspot territories in European forests. We provide a detailed description of the males' body and head posture, viewing direction, visual field and spatial resolution, as well as the visual environment. Pararge aegeria has sexually dimorphic eyes, the smallest interommatidial angles of males are around 1°, those of females 1.5°. Perching males face the antisolar direction with their retinal region of the highest resolution pointing at an angle of about 45° above the horizon; thus, looking at a rather even and dark background in front of which they likely have the best chance to detect a sunlit female passing through the sunspot.
|
|
| 10. |
- Borges, Renee M., et al.
(författare)
-
Patterns and processes in nocturnal and crepuscular pollination services
- 2016
-
Ingår i: Quarterly Review of Biology. - : University of Chicago Press. - 0033-5770 .- 1539-7718. ; 91:4, s. 389-418
-
Tidskriftsartikel (refereegranskat)abstract
- Night,dawn,and dusk have abiotic features that differ from the day. Illumination,wind speeds,turbulence,and temperatures are lower while humidity may be higher at night. Nocturnal pollination occurred in 30% of angiosperm families across 68% of orders,97% of families with C3,two-thirds of fam-ilies with crassulacean acid metabolism (CAM),and 71% dicot families with C4 photosynthesis. Despite its widespread occurence,nocturnal pollination occurs in more families with xerophytic adaptations than helophytes or mesophytes,suggesting that nocturnal flowering is primarily an adaptation to water stress since flowering is a water-intensive process. We propose the arid or water stress hypothesis for nocturnal flowering suggesting that plants facing water stress in a habitat (e.g.,deserts) or a habitat stratum (e.g.,upper canopy for epiphytes) gain a selective advantage by nocturnal flowering by reducing water loss through evapotranspiration,leading to larger flowers that provide more nectar or other resources,to support pollinators with higher rewards. Contrary to the wide taxonomic occurrence of nocturnal flowering,few animal taxa serve as nocturnal pollinators. We discuss the sensory and physiological abilities that enable pollinator movement,navigation,and detection of flowers within the nocturnal temporal niche and present a unified framework for investigation of nocturnal flowering and pollination.
|
|
