Intracellular optical physiology of the eye of the pyralid moth Amyelois

Abstract

AbstractAs in most nocturnal moths, the eyes of pyralid moths contain crystalline tracts formed by long, thin, distal extensions of the photoreceptor cells. Eyes of pyralid moths are unusual, however, because these thin extensions of the photoreceptor cells contain both pigment granules and rhabdomeric microvilli. Published anatomical and optical studies show that granules of both the photoreceptor cells and the primary/secondary pigment cells migrate as pyralid eyes adapt to light.The purpose of this paper is to describe noninvasive optical methods that characterize quantitatively the migration of pigment granules of both photoreceptor cells and pigment cells within the eye of the adult pyralid moth Amyelois. We find that: 1) Short, dim, monochromatic flashes (5 sec; 350–600 nm; quantum flux Q = 1010−1012 photons/cm2/sec) delivered to the dark‐adapted eye cause migration of the granules within photoreceptor cells, but no migration of the granules within pigment cells. The shape of a response is simple for the dimmest flashes and is complex for the brighter flashes. 2) The 12 photoreceptor cells that contribute microvilli to the distal rhabdom in each ommatidium are of three spectral types, maximally sensitive at about 350, 430, and 530 nm, respectively. 3) Short, bright flashes (Q > 1013) or long flashes (duration > 1 min; Q > 4 × 1012) delivered to the dark‐adapted eye cause migration of granules within pigment cells as well as receptor cells. Action spectra (350–665 nm) for movements of pigment‐cell granules are dominated by green‐receptors, with minor input from UV‐receptors and negligible input from the blue‐receptors.