The Dual Function of Orchid Bee Ocelli as Revealed by X-Ray Microtomography
Author
Summary, in English
Visually guided flight control in the rainforest is arguably
one of the most complex insect behaviors: illumination
varies dramatically depending on location
[1], and the densely cluttered environment blocks
out most of the sky [2]. What visual information do
insects sample for flight control in this habitat? To
begin answering this question, we determined the visual
fields of the ocelli—thought to play a role in attitude
stabilization of some flying insects [3–5]—of
an orchid bee, Euglossa imperialis. High-resolution
3D models of the ocellar system from X-ray microtomography
were used for optical ray tracing simulations.
Surprisingly, these showed that each ocellus
possesses two distinct visual fields—a focused
monocular visual field suitable for detecting features
elevated above the horizon and therefore assisting
with flight stabilization [3–5] and, unlike other ocelli
investigated to date [4, 6, 7], a large trinocular
fronto-dorsal visual field shared by all ocelli. Histological
analyses show that photoreceptors have
similar orientations within each ocellus and are likely
to be sensitive to polarized light, as in some other hymenopterans
[7, 8]. We also found that the average
receptor orientation is offset between the ocelli,
each having different axes of polarization sensitivity
relative to the head. Unlike the eyes of any other
insect described to date, this ocellar system meets
the requirements of a true polarization analyzer
[9, 10]. The ocelli of E. imperialis could provide
sensitive compass information for navigation in the
rainforest and, additionally, provide cues for visual
discrimination or flight control.
one of the most complex insect behaviors: illumination
varies dramatically depending on location
[1], and the densely cluttered environment blocks
out most of the sky [2]. What visual information do
insects sample for flight control in this habitat? To
begin answering this question, we determined the visual
fields of the ocelli—thought to play a role in attitude
stabilization of some flying insects [3–5]—of
an orchid bee, Euglossa imperialis. High-resolution
3D models of the ocellar system from X-ray microtomography
were used for optical ray tracing simulations.
Surprisingly, these showed that each ocellus
possesses two distinct visual fields—a focused
monocular visual field suitable for detecting features
elevated above the horizon and therefore assisting
with flight stabilization [3–5] and, unlike other ocelli
investigated to date [4, 6, 7], a large trinocular
fronto-dorsal visual field shared by all ocelli. Histological
analyses show that photoreceptors have
similar orientations within each ocellus and are likely
to be sensitive to polarized light, as in some other hymenopterans
[7, 8]. We also found that the average
receptor orientation is offset between the ocelli,
each having different axes of polarization sensitivity
relative to the head. Unlike the eyes of any other
insect described to date, this ocellar system meets
the requirements of a true polarization analyzer
[9, 10]. The ocelli of E. imperialis could provide
sensitive compass information for navigation in the
rainforest and, additionally, provide cues for visual
discrimination or flight control.
Publishing year
2016-05-23
Language
English
Pages
1319-1324
Publication/Series
Current Biology
Issue
26
Document type
Journal article
Publisher
Elsevier
Topic
- Zoology
- Other Physics Topics
Status
Published
Research group
- Lund Vision Group
ISBN/ISSN/Other
- ISSN: 1879-0445