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Visual sensitivity in the crepuscular owl butterfly Caligo memnon and the diurnal blue morpho Morpho peleides: a clue to explain the evolution of nocturnal apposition eyes?

Frederiksen, Rikard LU and Warrant, Eric LU (2008) In Journal of Experimental Biology 211(6). p.844-851
Abstract
Insects active in dim light, such as moths and many beetles, normally have superposition compound eyes to increase photon capture. But there are nocturnal and crepuscular insects - such as some species of bees, wasps and butterflies - that have apposition compound eyes. These are likely to have adaptations - including large eye and facet size and coarsened spatial and temporal resolution - that improve their sensitivity and thus their visual reliability. Is this also true for crepuscular insects that are active at intermediate intensities? To test this hypothesis, the visual performance of two closely related butterflies, the diurnal blue morpho Morpho peleides and the crepuscular owl butterfly Caligo memnon, were compared. Compared to the... (More)
Insects active in dim light, such as moths and many beetles, normally have superposition compound eyes to increase photon capture. But there are nocturnal and crepuscular insects - such as some species of bees, wasps and butterflies - that have apposition compound eyes. These are likely to have adaptations - including large eye and facet size and coarsened spatial and temporal resolution - that improve their sensitivity and thus their visual reliability. Is this also true for crepuscular insects that are active at intermediate intensities? To test this hypothesis, the visual performance of two closely related butterflies, the diurnal blue morpho Morpho peleides and the crepuscular owl butterfly Caligo memnon, were compared. Compared to the diurnal M. peleides, the crepuscular C. memnon does not appear to be adapted to a nocturnal lifestyle in terms of spatial resolution: the interommatidial angle Delta is similar in both species, and acceptance angles, Deltarho, are only marginally larger in C. memnon. Moreover, temporal resolution is only a little coarser in C. memnon compared to M. peleides. Using a model for sensitivity, we found that the eyes of C. memnon are about four times as light-sensitive as those of M. peleides in the frontal visual field, much of this difference being due to the larger facet diameters found in C. memnon. In summary, greater visual sensitivity has evolved in C. memnon than in M. peleides, showing that adaptations that improve sensitivity can be found not only in nocturnal apposition eyes, but also on a smaller scale in crepuscular apposition eyes. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Journal of Experimental Biology
volume
211
issue
6
pages
844 - 851
publisher
The Company of Biologists Ltd
external identifiers
  • pmid:18310109
  • wos:000254462700006
  • scopus:42549161512
ISSN
1477-9145
DOI
10.1242/jeb.012179
language
English
LU publication?
yes
id
fb26d3d3-a188-433c-80ef-51e139e1f8bb (old id 1052941)
date added to LUP
2008-04-28 14:34:20
date last changed
2017-06-04 03:38:06
@article{fb26d3d3-a188-433c-80ef-51e139e1f8bb,
  abstract     = {Insects active in dim light, such as moths and many beetles, normally have superposition compound eyes to increase photon capture. But there are nocturnal and crepuscular insects - such as some species of bees, wasps and butterflies - that have apposition compound eyes. These are likely to have adaptations - including large eye and facet size and coarsened spatial and temporal resolution - that improve their sensitivity and thus their visual reliability. Is this also true for crepuscular insects that are active at intermediate intensities? To test this hypothesis, the visual performance of two closely related butterflies, the diurnal blue morpho Morpho peleides and the crepuscular owl butterfly Caligo memnon, were compared. Compared to the diurnal M. peleides, the crepuscular C. memnon does not appear to be adapted to a nocturnal lifestyle in terms of spatial resolution: the interommatidial angle Delta is similar in both species, and acceptance angles, Deltarho, are only marginally larger in C. memnon. Moreover, temporal resolution is only a little coarser in C. memnon compared to M. peleides. Using a model for sensitivity, we found that the eyes of C. memnon are about four times as light-sensitive as those of M. peleides in the frontal visual field, much of this difference being due to the larger facet diameters found in C. memnon. In summary, greater visual sensitivity has evolved in C. memnon than in M. peleides, showing that adaptations that improve sensitivity can be found not only in nocturnal apposition eyes, but also on a smaller scale in crepuscular apposition eyes.},
  author       = {Frederiksen, Rikard and Warrant, Eric},
  issn         = {1477-9145},
  language     = {eng},
  number       = {6},
  pages        = {844--851},
  publisher    = {The Company of Biologists Ltd},
  series       = {Journal of Experimental Biology},
  title        = {Visual sensitivity in the crepuscular owl butterfly Caligo memnon and the diurnal blue morpho Morpho peleides: a clue to explain the evolution of nocturnal apposition eyes?},
  url          = {http://dx.doi.org/10.1242/jeb.012179},
  volume       = {211},
  year         = {2008},
}