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A 'bright zone' in male hoverfly (Eristalis tenax) eyes and associated faster motion detection and increased contrast sensitivity

Straw, Andrew D.; Warrant, Eric LU and O'Carroll, David C. (2006) In Journal of Experimental Biology 209(21). p.4339-4354
Abstract
Eyes of the hoverfly Eristalis tenax are sexually dimorphic such that males have a fronto-dorsal region of large facets. In contrast to other large flies in which large facets are associated with a decreased interommatidial angle to form a dorsal 'acute zone' of increased spatial resolution, we show that a dorsal region of large facets in males appears to form a 'bright zone' of increased light capture without substantially increased spatial resolution. Theoretically, more light allows for increased performance in tasks such as motion detection. To determine the effect of the bright zone on motion detection, local properties of wide field motion detecting neurons were investigated using localized sinusoidal gratings. The pattern of local... (More)
Eyes of the hoverfly Eristalis tenax are sexually dimorphic such that males have a fronto-dorsal region of large facets. In contrast to other large flies in which large facets are associated with a decreased interommatidial angle to form a dorsal 'acute zone' of increased spatial resolution, we show that a dorsal region of large facets in males appears to form a 'bright zone' of increased light capture without substantially increased spatial resolution. Theoretically, more light allows for increased performance in tasks such as motion detection. To determine the effect of the bright zone on motion detection, local properties of wide field motion detecting neurons were investigated using localized sinusoidal gratings. The pattern of local preferred directions of one class of these cells, the HS cells, in Eristalis is similar to that reported for the blowfly Calliphora. The bright zone seems to contribute to local contrast sensitivity; high contrast sensitivity exists in portions of the receptive field served by large diameter facet lenses of males and is not observed in females. Finally, temporal frequency tuning is also significantly faster in this frontal portion of the world, particularly in males, where it overcompensates for the higher spatial-frequency tuning and shifts the predicted local velocity optimum to higher speeds. These results indicate that increased retinal illuminance due to the bright zone of males is used to enhance contrast sensitivity and speed motion detector responses. Additionally, local neural properties vary across the visual world in a way not expected if HS cells serve purely as matched filters to measure yaw-induced visual motion. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
sexual dimorphism, insect vision, motion detection
in
Journal of Experimental Biology
volume
209
issue
21
pages
4339 - 4354
publisher
The Company of Biologists Ltd
external identifiers
  • wos:000242132500026
  • scopus:33845236729
ISSN
1477-9145
DOI
10.1242/jeb.02517
language
English
LU publication?
yes
id
5ae9c852-ea3e-4a5b-a096-40b87ff1b42f (old id 376550)
date added to LUP
2007-10-19 14:36:40
date last changed
2019-08-07 01:51:17
@article{5ae9c852-ea3e-4a5b-a096-40b87ff1b42f,
  abstract     = {Eyes of the hoverfly Eristalis tenax are sexually dimorphic such that males have a fronto-dorsal region of large facets. In contrast to other large flies in which large facets are associated with a decreased interommatidial angle to form a dorsal 'acute zone' of increased spatial resolution, we show that a dorsal region of large facets in males appears to form a 'bright zone' of increased light capture without substantially increased spatial resolution. Theoretically, more light allows for increased performance in tasks such as motion detection. To determine the effect of the bright zone on motion detection, local properties of wide field motion detecting neurons were investigated using localized sinusoidal gratings. The pattern of local preferred directions of one class of these cells, the HS cells, in Eristalis is similar to that reported for the blowfly Calliphora. The bright zone seems to contribute to local contrast sensitivity; high contrast sensitivity exists in portions of the receptive field served by large diameter facet lenses of males and is not observed in females. Finally, temporal frequency tuning is also significantly faster in this frontal portion of the world, particularly in males, where it overcompensates for the higher spatial-frequency tuning and shifts the predicted local velocity optimum to higher speeds. These results indicate that increased retinal illuminance due to the bright zone of males is used to enhance contrast sensitivity and speed motion detector responses. Additionally, local neural properties vary across the visual world in a way not expected if HS cells serve purely as matched filters to measure yaw-induced visual motion.},
  author       = {Straw, Andrew D. and Warrant, Eric and O'Carroll, David C.},
  issn         = {1477-9145},
  keyword      = {sexual dimorphism,insect vision,motion detection},
  language     = {eng},
  number       = {21},
  pages        = {4339--4354},
  publisher    = {The Company of Biologists Ltd},
  series       = {Journal of Experimental Biology},
  title        = {A 'bright zone' in male hoverfly (Eristalis tenax) eyes and associated faster motion detection and increased contrast sensitivity},
  url          = {http://dx.doi.org/10.1242/jeb.02517},
  volume       = {209},
  year         = {2006},
}