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Exploring the visual world of fossilized and modern fungus gnat eyes (Diptera : Keroplatidae) with X-ray microtomography

Taylor, Gavin J. LU ; Hall, Stephen A. LU ; Gren, Johan A. LU and Baird, Emily LU (2020) In Journal of the Royal Society, Interface 17(163).
Abstract

Animal eyes typically possess specialized regions for guiding different behavioural tasks within their specific visual habitat. These specializations, and evolutionary changes to them, can be crucial for understanding an animal's ecology. Here, we explore how the visual systems of some of the smallest flying insects, fungus gnats, have adapted to different types of forest habitat over time (approx. 30 Myr to today). Unravelling how behavioural, environmental and phylogenetic factors influence the evolution of visual specializations is difficult, however, because standard quantitative techniques often require fresh tissue and/or provide data in eye-centric coordinates that prevent reliable comparisons between species with different eye... (More)

Animal eyes typically possess specialized regions for guiding different behavioural tasks within their specific visual habitat. These specializations, and evolutionary changes to them, can be crucial for understanding an animal's ecology. Here, we explore how the visual systems of some of the smallest flying insects, fungus gnats, have adapted to different types of forest habitat over time (approx. 30 Myr to today). Unravelling how behavioural, environmental and phylogenetic factors influence the evolution of visual specializations is difficult, however, because standard quantitative techniques often require fresh tissue and/or provide data in eye-centric coordinates that prevent reliable comparisons between species with different eye morphologies. Here, we quantify the visual world of three gnats from different time periods and habitats using X-ray microtomography to create high-resolution three-dimensional models of the compound eyes of specimens in different preservation states-fossilized in amber, dried or stored in ethanol. We present a method for analysing the geometric details of individual corneal facets and for estimating and comparing the sensitivity, spatial resolution and field of view of species across geographical space and evolutionary time. Our results indicate that, despite their miniature size, fungus gnats do have variations in visual properties across their eyes. We also find some indication that these visual specializations vary across species and may represent adaptations to their different forest habitats. Overall, the findings demonstrate how such investigations can be used to study the evolution of visual specializations-and sensory ecology in general-across a range of insect taxa from different geographical locations and across time.

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author
; ; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
eye evolution, fossil, insect, optical analysis, visual specialization, X-ray microtomography
in
Journal of the Royal Society, Interface
volume
17
issue
163
publisher
The Royal Society of Canada
external identifiers
  • scopus:85078996827
  • pmid:32019468
ISSN
1742-5662
DOI
10.1098/rsif.2019.0750
language
English
LU publication?
yes
id
35d33065-32ad-49de-b97e-9babdc66a36c
date added to LUP
2020-02-19 13:27:58
date last changed
2021-04-27 01:33:22
@article{35d33065-32ad-49de-b97e-9babdc66a36c,
  abstract     = {<p>Animal eyes typically possess specialized regions for guiding different behavioural tasks within their specific visual habitat. These specializations, and evolutionary changes to them, can be crucial for understanding an animal's ecology. Here, we explore how the visual systems of some of the smallest flying insects, fungus gnats, have adapted to different types of forest habitat over time (approx. 30 Myr to today). Unravelling how behavioural, environmental and phylogenetic factors influence the evolution of visual specializations is difficult, however, because standard quantitative techniques often require fresh tissue and/or provide data in eye-centric coordinates that prevent reliable comparisons between species with different eye morphologies. Here, we quantify the visual world of three gnats from different time periods and habitats using X-ray microtomography to create high-resolution three-dimensional models of the compound eyes of specimens in different preservation states-fossilized in amber, dried or stored in ethanol. We present a method for analysing the geometric details of individual corneal facets and for estimating and comparing the sensitivity, spatial resolution and field of view of species across geographical space and evolutionary time. Our results indicate that, despite their miniature size, fungus gnats do have variations in visual properties across their eyes. We also find some indication that these visual specializations vary across species and may represent adaptations to their different forest habitats. Overall, the findings demonstrate how such investigations can be used to study the evolution of visual specializations-and sensory ecology in general-across a range of insect taxa from different geographical locations and across time.</p>},
  author       = {Taylor, Gavin J. and Hall, Stephen A. and Gren, Johan A. and Baird, Emily},
  issn         = {1742-5662},
  language     = {eng},
  number       = {163},
  publisher    = {The Royal Society of Canada},
  series       = {Journal of the Royal Society, Interface},
  title        = {Exploring the visual world of fossilized and modern fungus gnat eyes (Diptera : Keroplatidae) with X-ray microtomography},
  url          = {http://dx.doi.org/10.1098/rsif.2019.0750},
  doi          = {10.1098/rsif.2019.0750},
  volume       = {17},
  year         = {2020},
}