Adaptations for nocturnal and diurnal vision in the hawkmoth lamina.
Författare
Summary, in English
Animals use vision over a wide range of light intensities, from dim starlight to bright sunshine. For animals active in very dim light the visual system is challenged by several sources of visual noise. Adaptations in the eyes, as well as in the neural circuitry, have evolved to suppress the noise and enhance the visual signal, thereby improving vision in dim light. Among neural adaptations, spatial summation of visual signals from neighboring processing units is suggested to increase the reliability of signal detection and thus visual sensitivity. In insects, the likely neural candidates for carrying out spatial summation are the lamina monopolar cells (LMCs) of the first visual processing area of the insect brain (the lamina). We have classified LMCs in three species of hawkmoths having considerably different activity periods but very similar ecology - the diurnal Macroglossum stellatarum, the nocturnal Deilephila elpenor and the crepuscular-nocturnal Manduca sexta. Using this classification, we investigated the anatomical adaptations of hawkmoth LMCs suited for spatial summation. We found that specific types of LMCs have dendrites extending to significantly more neighboring cartridges in the two nocturnal and crepuscular species than in the diurnal species, making these LMC types strong candidates for spatial summation. Moreover, while the absolute number of cartridges visited by the LMCs differed between the two dim-light species, their dendritic extents were very similar in terms of visual angle, possibly indicating a limiting spatial acuity. Interestingly, the overall size of the lamina neuropil did not correlate with the size of its LMCs. This article is protected by copyright. All rights reserved.
Avdelning/ar
Publiceringsår
2016
Språk
Engelska
Sidor
160-175
Publikation/Tidskrift/Serie
Journal of Comparative Neurology
Volym
524
Issue
1
Dokumenttyp
Artikel i tidskrift
Förlag
John Wiley & Sons Inc.
Ämne
- Zoology
Status
Published
Forskningsgrupp
- Lund Vision Group
ISBN/ISSN/Övrigt
- ISSN: 1096-9861