scholarly journals Spatial tuning of translational optic flow responses in hawkmoths of varying body size

2021 ◽  
Author(s):  
Rebecca Grittner ◽  
Emily Baird ◽  
Anna Stöckl
Keyword(s):  
Body Size ◽  
Flight Control ◽  
Optic Flow ◽  
Visual Cues ◽  
Flight Tunnel ◽  
Compound Eyes ◽  
Eye Size ◽  
Spatial Frequencies ◽  
Macroglossum Stellatarum ◽  
Control Response

AbstractTo safely navigate their environment, flying insects rely on visual cues, such as optic flow. Which cues insects can extract from their environment depends closely on the spatial and temporal response properties of their visual system. These in turn can vary between individuals that differ in body size. How optic flow-based flight control depends on the spatial structure of visual cues, and how this relationship scales with body size, has previously been investigated in insects with apposition compound eyes. Here, we characterised the visual flight control response limits and their relationship to body size in an insect with superposition compound eyes: the hummingbird hawkmoth Macroglossum stellatarum. We used the hawkmoths’ centring response in a flight tunnel as a readout for their reception of translational optic flow stimuli of different spatial frequencies. We show that their responses cut off at different spatial frequencies when translational optic flow was presented on either one, or both tunnel walls. Combined with differences in flight speed, this suggests that their flight control was primarily limited by their temporal rather than spatial resolution. We also observed strong individual differences in flight performance, but no correlation between the spatial response cutoffs and body or eye size.

scholarly journals Nocturnal insects use optic flow for flight control

2011 ◽  
Vol 7 (4) ◽  
pp. 499-501 ◽  
Author(s):  
Emily Baird ◽  
Eva Kreiss ◽  
William Wcislo ◽  
Eric Warrant ◽  
Marie Dacke
Keyword(s):  
Flight Control ◽  
Optic Flow ◽  
Visual Information ◽  
Visual Cues ◽  
Bombus Terrestris ◽  
Flight Tunnel ◽  
Cluttered Environments ◽  
Flying Insects ◽  
Dim Light ◽  
Control Flight

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.

scholarly journals Visual and movement memories steer foraging bumblebees along habitual routes

2021 ◽  
Author(s):  
Olivier J.N. Bertrand ◽  
Charlotte Doussot ◽  
Tim Siesenop ◽  
Sridhar Ravi ◽  
Martin Egelhaaf
Keyword(s):  
Flight Control ◽  
Optic Flow ◽  
Visual Information ◽  
Path Integration ◽  
Bombus Terrestris ◽  
Flight Tunnel ◽  
Experimental Paradigm ◽  
Insect Navigation ◽  
Animal Navigation ◽  
Observed Behaviour

One persistent question in animal navigation is how animals follow habitual routes between their home and a food source. Our current understanding of insect navigation suggests an interplay between visual memories, collision avoidance and path integration, the continuous integration of distance and direction travelled. However, these behavioural modules have to be continuously updated with instantaneous visual information. In order to alleviate this need, the insect could learn and replicate habitual movements (“movement memories”) around objects (e.g. a bent trajectory around an object) to reach its destination. We investigated whether bumblebees, Bombus terrestris, learn and use movement memories en route to their home. Using a novel experimental paradigm, we habituated bumblebees to establish a habitual route in a flight tunnel containing “invisible” obstacles. We then confronted them with conflicting cues leading to different choice directions depending on whether they rely on movement or visual memories. The results suggest that they use movement memories to navigate, but also rely on visual memories to solve conflicting situations. We investigated whether the observed behaviour was due to other guidance systems, such as path integration or optic flow-based flight control, and found that neither of these systems was sufficient to explain the behaviour.

scholarly journals Differences in orthodenticle expression promote ommatidial size variation between Drosophila species

2021 ◽  
Author(s):  
Montserrat Torres-Oliva ◽  
Elisa Buchberger ◽  
Alexandra D. Buffry ◽  
Maike Kittelmann ◽  
Lauren Sumner-Rooney ◽  
...  
Keyword(s):  
Natural Variation ◽  
Gene Expression Analysis ◽  
Compound Eye ◽  
Chromosomal Region ◽  
Size Variation ◽  
Compound Eyes ◽  
Positional Candidate ◽  
Eye Size ◽  
Drosophila Mauritiana ◽  
Differential Timing

The compound eyes of insects exhibit extensive variation in ommatidia number and size, which affects how they see and underlies adaptations in their vision to different environments and lifestyles. However, very little is known about the genetic and developmental bases underlying differences in compound eye size. We previously showed that the larger eyes of Drosophila mauritiana compared to D. simulans is caused by differences in ommatidia size rather than number. Furthermore, we identified an X-linked chromosomal region in D. mauritiana that results in larger eyes when introgressed into D. simulans. Here, we used a combination of fine-scale mapping and gene expression analysis to further investigate positional candidate genes on the X chromosome. We found that orthodenticle is expressed earlier in D. mauritiana than in D. simulans during ommatidial maturation in third instar larvae, and we further show that this gene is required for the correct organisation and size of ommatidia in D. melanogaster. Using ATAC-seq, we have identified several candidate eye enhancers of otd as well as potential direct targets of this transcription factor that are differentially expressed between D. mauritiana and D. simulans. Taken together, our results suggest that differential timing of otd expression contributes to natural variation in ommatidia size between D. mauritiana and D. simulans, which provides new insights into the mechanisms underlying the regulation and evolution of compound eye size in insects.

scholarly journals The visual cues that drive the self-assessment of body size: Dissociation between fixation patterns and the key areas of the body for accurate judgement

Body Image ◽  
2019 ◽  
Vol 29 ◽  
pp. 31-46 ◽  
Author(s):  
Kamila R. Irvine ◽  
Kristofor McCarty ◽  
Thomas V. Pollet ◽  
Katri K. Cornelissen ◽  
Martin J. Tovée ◽  
...  
Keyword(s):  
Body Size ◽  
Visual Cues ◽  
The Body ◽  
The Self ◽  
Self Assessment

Body-size scaling of metabolic rate in the trilobite Eldredgeops rana

Paleobiology ◽  
2013 ◽  
Vol 39 (1) ◽  
pp. 109-122 ◽  
Author(s):  
Douglas S. Glazier ◽  
Matthew G. Powell ◽  
Travis J. Deptola
Keyword(s):  
Body Size ◽  
Metabolic Rate ◽  
Cell Size ◽  
The Body ◽  
Cell Multiplication ◽  
Compound Eyes ◽  
Metabolic Scaling ◽  
Size Scaling ◽  
Size Model ◽  
Facet Size

We infer the body-size scaling slope of metabolic rate in a trilobite by applying a cell-size model that has been proposed to explain metabolic scaling in living organisms. This application is especially tractable in fossil arthropods with well-preserved compound eyes because the number and size of eye facets appear to be useful proxies for the relative number and size of cells in the body. As a case study, we examined the ontogenetic scaling of facet size and number in a ∼390-Myr-old local assemblage of the trilobite Eldredgeops rana, which has well-preserved compound eyes and a wide body-size range. Growth in total eye lens area resulted from increases in both facet area and number in relatively small (presumably young) specimens, but only from increases in facet area in large (presumably more mature) specimens. These results suggest that early growth in E. rana involved both cell multiplication and enlargement, whereas later growth involved only cell enlargement. If the cell-size model is correct, then metabolic rate scaled allometrically in E. rana, and the scaling slope of log metabolic rate versus log body mass decreased from ∼0.85 to 0.63 as these animals grew. This inferred age-specific change in metabolic scaling is consistent with similar changes frequently observed in living animals. Additional preliminary analyses of literature data on other trilobites also suggest that the metabolic scaling slope was <1 in benthic species, but ∼1 in pelagic species, as has also been observed in living invertebrates. The eye-facet size (EFS) method featured here opens up new possibilities for examining the bioenergetic allometry of extinct arthropods.

Investigating the role of body size, ecology, and behavior in anuran eye size evolution

2019 ◽  
Vol 33 (4) ◽  
pp. 585-598 ◽  
Author(s):  
Chun Hua Huang ◽  
Mao Jun Zhong ◽  
Wen Bo Liao ◽  
Alexander Kotrschal
Keyword(s):  
Body Size ◽  
Eye Size ◽  
Size Evolution ◽  
And Behavior

Visual fields of the compound eyes of four species of Cicindelidae (Coleoptera)

1980 ◽  
Vol 58 (3) ◽  
pp. 326-336 ◽  
Author(s):  
J. E. Kuster ◽  
W. G. Evans
Keyword(s):  
Visual Field ◽  
North American ◽  
Visual Fields ◽  
Morphological Characters ◽  
Head Size ◽  
Compound Eyes ◽  
Eye Size ◽  
Nocturnal Species ◽  
The Relationship ◽  
Diurnal Species

Visual field angles were measured around the circumference of the compound eyes of four species of North American Cicindelidae and plotted on Mollweide homolographs. Areas of monoscopic and stereoscopic visual fields and blind areas were calculated. In contrast to the nocturnal species (Amblycheila schwarzi and Omus californicus), the crepuscular species (Megacephala Carolina) and the diurnal species (Cicindela tranquebarica) have more ommatidia and larger eye size: head size ratios, total visual fields, and stereoscopic visual fields. These characters are considered to be derived and confirm the phylogenetic sequence of the four genera that was previously based on other morphological characters. The relationship between these characters and the biology of each species is also discussed.

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