1.2 Why Sensory Ecology Needs to Become
More Evolutionary - Insect Color Vision as a
Case in Point
Lars Chittka 1 and Adriana Briscoe 2
1 Zoologie II, Biozentrum, Am Hubland, 97074 WUrzburg, Germany
2 Department of Molecular and Cellular Biology, Life Sciences South 444/1007
E. Lowell, Tucson, Arizona 85721, USA
Abstract
Many of the subtleties in the evolutionary tuning of sensory systems still escape
us. Insect color vision is a typical case. While we know much about its
mechanisms, the abundant adaptive explanations of its components are often
ornate speculations. We advocate using an evolutionary approach to understand
why different animals see the world in different colors. Such an approach must
include ( 1) phylogenetic analyses, which should help identify patterns of
adaptation, constraint and history; (2) molecular studies, to predict how plastic the
relevant genes will be in the face of particular selective pressures; (3) assessments
of interindividual variance, to see if the raw material for evolution exists; (4) a
consideration of pleiotropic effects, where selection on visual pigments may be
affected indirectly through correlated characters; (5) biogeography, to explore if
populations living in different visual habitats have adapted to those differences;
(6) a consideration of random evolutionary processes; (7) selection experiments,
to test for heritability of traits and to simulate the influences of strong directional
selection; (8) fitness tests: to show that a trait is adaptive, we must show
empirically that this trait confers greater fitness to its bearers, compared with
conspecifics which lack this trait.
Key words Color vision, evolution, insects, visual ecology, visual pigments
1 Introduction
One major focus of sensory ecology has long been the question why many
animals see the world through color receptors so different from our own.
Traditionally, the field has concentrated on adaptive explanations. We are used to
thinking that if there were differences between species, this must reflect
adaptations to different photic environments, whereas if animals share similar
color receptors, they must live under similar selective pressures. Fish dwelling in
progressively deeper habitats possess rods whose sensitivity is more and more
shifted into the blue, thus matching the changing spectral distribution of the
More Evolutionary - Insect Color Vision as a
Case in Point
Lars Chittka 1 and Adriana Briscoe 2
1 Zoologie II, Biozentrum, Am Hubland, 97074 WUrzburg, Germany
2 Department of Molecular and Cellular Biology, Life Sciences South 444/1007
E. Lowell, Tucson, Arizona 85721, USA
Abstract
Many of the subtleties in the evolutionary tuning of sensory systems still escape
us. Insect color vision is a typical case. While we know much about its
mechanisms, the abundant adaptive explanations of its components are often
ornate speculations. We advocate using an evolutionary approach to understand
why different animals see the world in different colors. Such an approach must
include ( 1) phylogenetic analyses, which should help identify patterns of
adaptation, constraint and history; (2) molecular studies, to predict how plastic the
relevant genes will be in the face of particular selective pressures; (3) assessments
of interindividual variance, to see if the raw material for evolution exists; (4) a
consideration of pleiotropic effects, where selection on visual pigments may be
affected indirectly through correlated characters; (5) biogeography, to explore if
populations living in different visual habitats have adapted to those differences;
(6) a consideration of random evolutionary processes; (7) selection experiments,
to test for heritability of traits and to simulate the influences of strong directional
selection; (8) fitness tests: to show that a trait is adaptive, we must show
empirically that this trait confers greater fitness to its bearers, compared with
conspecifics which lack this trait.
Key words Color vision, evolution, insects, visual ecology, visual pigments
1 Introduction
One major focus of sensory ecology has long been the question why many
animals see the world through color receptors so different from our own.
Traditionally, the field has concentrated on adaptive explanations. We are used to
thinking that if there were differences between species, this must reflect
adaptations to different photic environments, whereas if animals share similar
color receptors, they must live under similar selective pressures. Fish dwelling in
progressively deeper habitats possess rods whose sensitivity is more and more
shifted into the blue, thus matching the changing spectral distribution of the