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| 2. |
- Arnadottir, Anna, et al.
(författare)
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The Meridian S03E04 : Finding the way using starlight
- 2023
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Konstnärligt arbete (övrigt vetenskapligt/konstnärligt)abstract
- Astronomers, such as Nic and Rebecca, are not the only ones orienting themselves using the stars. Animals, big and small, also navigate by starlight. In this last episode of the third season we invited Prof. Marie Dacke from the Department of Biology over to tell us about her research on the subject.In this third season we are also including some Cosmic Curiosities. These are some ideas, events or trivia from astronomic history that Ross, Victor and Lucian feel are worth bringing out of obscurity for one more look.
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| 3. |
- Baird, Emily, et al.
(författare)
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Bearing selection in ball-rolling dung beetles: is it constant?
- 2010
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Ingår i: Journal of Comparative Physiology A: Neuroethology, Sensory, Neural, and Behavioral Physiology. - : Springer Science and Business Media LLC. - 1432-1351. ; 196, s. 801-806
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Tidskriftsartikel (refereegranskat)abstract
- Ball rolling in dung beetles is thought to have evolved as a means to escape intense inter- and intra-specific competition at the dung pile. Accordingly, dung beetles typically roll along a straight-line path away from the pile, this being the most effective escape strategy for transporting dung to a suitable burial site. In this study, we investigate how individual diurnal dung beetles, Scarabaeus (Kheper) nigroaeneus, select the compass bearing of their straight-line rolls. In particular, we examine whether roll bearings are constant with respect to geographic cues, celestial cues, or other environmental cues (such as wind direction). Our results reveal that the roll bearings taken by individual beetles are not constant with respect to geographic or celestial references. Environmental cues appear to have some influence over bearing selection, although the relationship is not strong. Furthermore, the variance in roll bearing that we observe is not affected by the presence or absence of other beetles. Thus, rather than being constant for individual beetles, bearing selection varies each time a beetle makes a ball and rolls it away from the dung pile. This strategy allows beetles to make an efficient escape from the dung pile while minimizing the chance of encountering competition.
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| 4. |
- Baird, Emily, et al.
(författare)
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Finding the gap : A brightness-based strategy for guidance in cluttered environments
- 2016
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Ingår i: Royal Society of London. Proceedings B. Biological Sciences. - : The Royal Society. - 0962-8452. ; 283:1828
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Tidskriftsartikel (refereegranskat)abstract
- The ability to move safely between obstacles is critical for animals that fly rapidly through cluttered environments but surprisingly little is known about how they achieve this. Do they reactively avoid obstacles or do they instead fly towards the gaps between them? If they aim towards gaps, what information do they use to detect and fly through them? Here, we aim to answer these questions by presenting orchid bees with different apertures. When negotiating gaps, orchid bees locate and fly close to the point that gives themgreatest clearance from the edges. The cue that they use to pinpoint this spot is the brightness gradient formed across the aperture. Furthermore, we find that orchid bees also rely on brightness cues to locate gaps that are sufficiently large to negotiate safely. The advantage of using brightness for locating and negotiating gaps in a cluttered environment is that it provides information about the safest path through obstacles, at least in a forest environment. This brightness-based guidance strategy for gap detection and negotiation represents a fast, computationally simple and efficient mechanism to identify the clearest path through a forest and is, therefore, likely to represent a more general mechanism used by other animals.
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| 5. |
- Baird, Emily, et al.
(författare)
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Minimum viewing angle for visually guided ground speed control in bumblebees.
- 2010
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Ingår i: Journal of Experimental Biology. - : The Company of Biologists. - 1477-9145 .- 0022-0949. ; 213:10, s. 1625-1632
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Tidskriftsartikel (refereegranskat)abstract
- To control flight, flying insects extract information from the pattern of visual motion generated during flight, known as optic flow. To regulate their ground speed, insects such as honeybees and Drosophila hold the rate of optic flow in the axial direction (front-to-back) constant. A consequence of this strategy is that its performance varies with the minimum viewing angle (the deviation from the frontal direction of the longitudinal axis of the insect) at which changes in axial optic flow are detected. The greater this angle, the later changes in the rate of optic flow, caused by changes in the density of the environment, will be detected. The aim of the present study is to examine the mechanisms of ground speed control in bumblebees and to identify the extent of the visual range over which optic flow for ground speed control is measured. Bumblebees were trained to fly through an experimental tunnel consisting of parallel vertical walls. Flights were recorded when (1) the distance between the tunnel walls was either 15 or 30 cm, (2) the visual texture on the tunnel walls provided either strong or weak optic flow cues and (3) the distance between the walls changed abruptly halfway along the tunnel's length. The results reveal that bumblebees regulate ground speed using optic flow cues and that changes in the rate of optic flow are detected at a minimum viewing angle of 23-30 deg., with a visual field that extends to approximately 155 deg. By measuring optic flow over a visual field that has a low minimum viewing angle, bumblebees are able to detect and respond to changes in the proximity of the environment well before they are encountered.
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| 6. |
- Baird, Emily, et al.
(författare)
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Nocturnal insects use optic flow for flight control.
- 2011
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Ingår i: Biology letters. - : The Royal Society. - 1744-9561 .- 1744-957X. ; 7, s. 499-501
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Tidskriftsartikel (refereegranskat)abstract
- To avoid collisions when navigating through cluttered environments, flying insects must control their flight so that their sensory systems have time to detect obstacles and avoid them. To do this, day-active insects rely primarily on the pattern of apparent motion generated on the retina during flight (optic flow). However, many flying insects are active at night, when obtaining reliable visual information for flight control presents much more of a challenge. To assess whether nocturnal flying insects also rely on optic flow cues to control flight in dim light, we recorded flights of the nocturnal neotropical sweat bee, Megalopta genalis, flying along an experimental tunnel when: (i) the visual texture on each wall generated strong horizontal (front-to-back) optic flow cues, (ii) the texture on only one wall generated these cues, and (iii) horizontal optic flow cues were removed from both walls. We find that Megalopta increase their groundspeed when horizontal motion cues in the tunnel are reduced (conditions (ii) and (iii)). However, differences in the amount of horizontal optic flow on each wall of the tunnel (condition (ii)) do not affect the centred position of the bee within the flight tunnel. To better understand the behavioural response of Megalopta, we repeated the experiments on day-active bumble-bees (Bombus terrestris). Overall, our findings demonstrate that despite the limitations imposed by dim light, Megalopta-like their day-active relatives-rely heavily on vision to control flight, but that they use visual cues in a different manner from diurnal insects.
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| 7. |
- Baird, Emily, et al.
(författare)
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The dung beetle dance: an orientation behaviour?
- 2012
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Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 7:1
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Tidskriftsartikel (refereegranskat)abstract
- An interesting feature of dung beetle behaviour is that once they have formed a piece of dung into a ball, they roll it along a straight path away from the dung pile. This straight-line orientation ensures that the beetles depart along the most direct route, guaranteeing that they will not return to the intense competition (from other beetles) that occurs near the dung pile. Before rolling a new ball away from the dung pile, dung beetles perform a characteristic "dance," in which they climb on top of the ball and rotate about their vertical axis. This dance behaviour can also be observed during the beetles' straight-line departure from the dung pile. The aim of the present study is to investigate the purpose of the dung beetle dance. To do this, we explored the circumstances that elicit dance behaviour in the diurnal ball-rolling dung beetle, Scarabaeus (Kheper) nigroaeneus. Our results reveal that dances are elicited when the beetles lose control of their ball or lose contact with it altogether. We also find that dances can be elicited by both active and passive deviations of course and by changes in visual cues alone. In light of these results, we hypothesise that the dung beetle dance is a visually mediated mechanism that facilitates straight-line orientation in ball-rolling dung beetles by allowing them to 1) establish a roll bearing and 2) return to this chosen bearing after experiencing a disturbance to the roll path.
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| 8. |
- Baird, Emily, et al.
(författare)
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Visual flight control in naturalistic and artificial environments.
- 2012
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Ingår i: Journal of Comparative Physiology A: Neuroethology, Sensory, Neural, and Behavioral Physiology. - : Springer Science and Business Media LLC. - 1432-1351. ; 198:12, s. 869-876
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Tidskriftsartikel (refereegranskat)abstract
- Although the visual flight control strategies of flying insects have evolved to cope with the complexity of the natural world, studies investigating this behaviour have typically been performed indoors using simplified two-dimensional artificial visual stimuli. How well do the results from these studies reflect the natural behaviour of flying insects considering the radical differences in contrast, spatial composition, colour and dimensionality between these visual environments? Here, we aim to answer this question by investigating the effect of three- and two-dimensional naturalistic and artificial scenes on bumblebee flight control in an outdoor setting and compare the results with those of similar experiments performed in an indoor setting. In particular, we focus on investigating the effect of axial (front-to-back) visual motion cues on ground speed and centring behaviour. Our results suggest that, in general, ground speed control and centring behaviour in bumblebees is not affected by whether the visual scene is two- or three dimensional, naturalistic or artificial, or whether the experiment is conducted indoors or outdoors. The only effect that we observe between naturalistic and artificial scenes on flight control is that when the visual scene is three-dimensional and the visual information on the floor is minimised, bumblebees fly further from the midline of the tunnel. The findings presented here have implications not only for understanding the mechanisms of visual flight control in bumblebees, but also for the results of past and future investigations into visually guided flight control in other insects.
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| 9. |
- Balkenius, Anna, et al.
(författare)
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Learning of Multi-Modal Stimuli in Hawkmoths
- 2013
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Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 8
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Tidskriftsartikel (refereegranskat)abstract
- The hawkmoth, Manduca sexta, uses both colour and odour to find flowers when foraging for nectar. In the present study we investigated how vision and olfaction interact during learning. Manduca sexta were equally attracted to a scented blue coloured feeding target (multimodal stimulus) as to one that does not carry any scent (unimodal stimulus; visual) or to an invisible scented target (unimodal stimulus; odour). This naive attraction to multimodal as well as to unimodal stimuli could be manipulated through training. Moths trained to feed from a blue, scented multimodal feeding target will, when tested in a set-up containing all three feeding targets, select the multimodal target as well as the scented, unimodal target, but ignore the visual target. Interestingly, moths trained to feed from a blue, unimodal visual feeding target will select the visual target as well as the scented, multimodal target, but ignore the unimodal odour target. Our results indicate that a multimodal target is perceived as two separate modalities, colour and odour, rather than as a unique fused target. These findings differ from earlier studies of desert ants that perceive combined visual and odour signals as a unique fused stimulus following learning trials.
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| 10. |
- Balkenius, Anna, et al.
(författare)
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The Approach Behaviour of the Hawkmoth Manduca sexta toward Multi-modal Stimuli: A Simulation Model
- 2010
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Ingår i: From Animals to Animats 11 : 11th International Conference on Simulation of Adaptive Behavior, SAB 2010, Paris - Clos Lucé, France, August 25-28, 2010. Proceedings - 11th International Conference on Simulation of Adaptive Behavior, SAB 2010, Paris - Clos Lucé, France, August 25-28, 2010. Proceedings. - 9783642151927 - 9783642151934 ; 6226, s. 232-241
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Konferensbidrag (refereegranskat)
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