The eye of the parthenogenetic and minute moth Ectoedemia argyropeza (Lepidoptera: Nepticulidae)

Title:

The eye of the parthenogenetic and minute moth Ectoedemia argyropeza (Lepidoptera: Nepticulidae)

Creator:

Honkanen, Anna and Meyer-Rochow, Victor Benno

Identifier:

https://cdk.lib.cas.cz/client/handle/uuid:129095fb-30cc-4548-ac2b-bb077f222bdd
uuid:129095fb-30cc-4548-ac2b-bb077f222bdd

Subject:

Nepticuloidea, Microlepidoptera, vision, facets, and retinal ultrastructure

Type:

article, model:article, and TEXT

Description:

Ectoedemia argyropeza (Zeller, 1839) possesses a compound eye that exhibits features of both apposition and superposition type eyes. Like apposition eyes, the eye of E. argyropeza lacks a clear-zone, which in superposition eyes separates the distal dioptric from the proximal light-perceiving structures. On the other hand, a tracheal layer around the proximal ends of the rhabdom as well as a well-developed corneal nipple array on the corneal surfaces are features that E. argyropeza shares with the larger moths. Unique, and so far only seen to this extreme degree in any insect, is the hourglass-shape of E. argyropeza's rhabdom, in which two almost equally voluminous regions (one distal, one proximal and formed in both cases by seven rhabdomeres) are connected by a narrow waist-like region of the retinula. An eighth retinula cell, not participating in rhabdom formation, is developed as a basal cell, just above the basement membrane. The eye responds with photomechanical changes to dark/light adaptation, but while the proximal rhabdom moiety slightly expands (as expected) in the dark, the distal rhabdom increases its diameter only upon light-adaptation. Owing to the tandem position of the two rhabdom moities, it is in the light-adapted state that the distally-placed rhabdom is favoured, while the proximal rhabdom plays a more important role at low ambient light levels. With screening pigments withdrawn, tracheal tapetum exposed, and distal rhabdom diameters reduced, the proximal and in the dark enlarged rhabdom is then in a position to capture photons that have entered the eye through not only the ommatidial window above, but other facets as well even in the absence of a clear-zone and superposition optics.

Language:

English

Rights:

http://creativecommons.org/publicdomain/mark/1.0/
policy:public

Source:

European Journal of Entomology | 2009 Volume:106 | Number:4

Harvested from:

CDK

Metadata only:

false