Ommatidial heterogeneity in the compound eye of the male small white butterfly, Pieris rapae crucivora

Abstract

Ommatidial heterogeneity in the compound eye of the male small white butterfly, Pieris rapae crucivora Qiu, XD; Vanhoutte, KAJ; Stavenga, Doekele; Arikawa, K; Qiu, Xudong Take-down policy If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim.Downloaded from the University of Groningen/UMCG research database (Pure): http://www.rug.nl/research/portal. For technical reasons the number of authors shown on this cover page is limited to 10 maximum. Download date: 11-05-2018Abstract The ommatidia in the ventral two-thirds of the compound eye of male Pieris rapae crucivora are not uniform. Each ommatidium contains nine photoreceptor cells. Four cells (R1-4) form the distal two-thirds of the rhabdom, four cells (R5-8) approximately occupy the proximal one-third of the rhabdom, and the ninth cell (R9) takes up a minor basal part of the rhabdom. The R5-8 photoreceptor cells contain clusters of reddish pigment adjacent to the rhabdom. From the position of the pigment clusters, three types of ommatidia can be identified: the trapezoidal (type I), square (type II), and rectangular type (type III). Microspectrophotometry with an epi-illumination microscope has revealed that the reflectance spectra of type I and type III ommatidia peak at 635 nm and those of type II ommatidia peak at 675 nm. The bandwith of the reflectance spectra is 40-50 nm. Type II ommatidia strongly fluoresce under ultra-violet and violet epi-illumination. The three types of ommatidia are randomly distributed. The ommatidial heterogeneity is presumably crucial for color discrimination.

Colour in the eyes of insects

“…A rich mixture of differently coloured ommatidia usually marks the ventral area, often with a distinct red component (e, g, j-m). The dark ommatidia in f reflect well in the deep-red (Qiu et al 2002;Stavenga 2002) The common yellow-red eye shine can be understood with a simple model of a butterfly ommatidium, which is based on our present knowledge of the small white, Pieris rapae (Qiu et al 2002), and the Japanese yellow swallowtail, Papilio xuthus (Arikawa and Stavenga 1997;Arikawa et al 1999a). These butterfly species have a tiered rhabdom.…”

“…6a, inset). Taking a rhabdom length of 400 lm (Qiu et al 2002), known visual pigment templates (Stavenga et al 1993), rhodopsins with peak wavelengths 360 nm (UV), 450 nm (B) and 540 nm (G), respectively (Fig. 6a), and a visual pigment extinction coefficient of 0.005 lm -1 (Warrant and Nilsson 1998), the resulting decrease in light flux in the rhabdom can be calculated (Fig.…”

Visual pigment spectra of the comma butterfly, Polygonia c-album, derived from in vivo epi-illumination microspectrophotometry

“…The eyes contain a few classes of randomly distributed ommatidia, with often a marked dorso-ventral regionalization (Arikawa and Stavenga 1997;Kitamoto et al 1998). A similar situation exists in the pierid butterfly Pieris rapae (Qiu et al 2002;Wakakuwa et al 2004) and the nymphalid Vanessa cardui (Briscoe et al 2003). Heterogeneity and regionalization seem to be general characteristics of butterfly eyes (Stavenga et al 2001;Warrant et al 2003).…”

“…The observed color of the eye shine is attributed to the combined effect of the selective spectral absorption by visual pigments and the interference reflection properties of the tapetum (Miller and Bernard 1968;Stavenga 2002b). An additional spectral effect can result from colored screening pigments, which in several occasions surround the rhabdom (Ribi 1979;Arikawa and Stavenga 1997;Qiu et al 2002). The eye shine is only seen in dark-adapted eyes.…”

“…The eye shine is only seen in dark-adapted eyes. Illumination rapidly extinguishes the eye shine, because pupillary pigments inside the photoreceptor cells migrate towards the rhabdom upon light adaptation and thus effectively reduce the propagating light flux (Stavenga et al 1977;Qiu et al 2002).…”