@article{oai:ir.soken.ac.jp:00004186,
 author = {蟻川, 謙太郎 and QIU, Xudong and VANHOUTTE, Kurt A.J. and STAVENGA, Doekele G. and ARIKAWA, Kentaro},
 issue = {3},
 journal = {Cell and Tissue Research, Cell and Tissue Research},
 month = {Mar},
 note = {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.},
 pages = {371--379},
 title = {Ommatidial heterogeneity in the compound eye of the male small white butterfly, Pieris rapae crucivora},
 volume = {307},
 year = {2002}
}