Eye pigments of the blood-sucking insect, Triatoma infestans klug (Hemiptera, Reduviidae)

Abstract

The pigmentation of black (wild) and red (mutant) eyes of Triatoma infestans was studied spectrophotometrically and compared with red-eyed (wild) and white-eyed (mutant) forms of Drosophila melanogaster. The spectral absorption profiles of the black and red eye pigments of T. infestans were similar to each other and to that of the wild-type eyes of D. melanogaster. The similarity to the wild form of D. melanogaster indicated that both eye forms of T. infestans contained ommochromes of the xanthommatin type, a finding confirmed by ascending paper chromatography. Pteridines, melanins, and ommins were not detected as eye pigments in T. infestans. The eye color difference in T. infestans was assumed to be a function of the xanthommatin concentration, with a smaller content of ommochrome in red eyes, although this probably did not affect the insect's visual acuity. These data support other findings regarding the similarities between black-and red-eyed specimens of T. infestans for other characteristics.Key words: Triatoma infestans, eye color, black eyes, red-eyed mutant, ommochrome, spectral absorption profiles. RESUMO Pigmentos de olho em Triatoma infestans (Hemiptera, Reduviidae)A pigmentação de olhos pretos (forma selvagem) e vermelhos (forma mutante) de Triatoma infestans foi estudada por espectrofotometria e comparada à de olhos vermelhos (selvagem) e brancos (mutante) de Drosophila melanogaster. Os perfis do espectro de absorção dos pigmentos de olho preto e vermelho de T. infestans foram semelhantes entre si e ao dos olhos de tipo selvagem de D. melanogaster. A similaridade com a forma selvagem de D. melanogaster indicou que ambos os tipos de olho de T. infestans continham omocromos do tipo xantomatina, o que foi confirmado por cromatografia ascendente em papel. Não foram detectadas pteridinas, melaninas e ominas como pigmentos de olho em T. infestans. A diferença na cor de olho em T. infestans foi considerada uma função da concentração de xantomatina, sendo menor o conteúdo de omocromo nos olhos vermelhos, embora isso provavelmente não afete a acuidade visual do inseto. Esses resultados estão de acordo com dados de outros autores quanto a semelhanças envolvendo outras características entre espécimes de olho preto e vermelho de T. infestans.Palavras-chave: Triatoma infestans, cor de olho, olhos pretos, mutante de olho vermelho, omocromo, espectro de absorção. Braz. J. Biol., 65(3): 477-481, 2005 478 MORAES, A. S. et al.

CRISPR/Cas9‐mediated knockout of the eye pigmentation gene white leads to alterations in colour of head spots in the oriental fruit fly, Bactrocera dorsalis

“…In insects, two classes of pigment, tryptophan‐derived ommochromes and guanine‐derived pteridines, determine eye colour; both are used in some Diptera and Orthoptera (Summers et al ., ), whereas the honey bee ( Apis mellifera ), mosquitoes (Diptera: Culicidae), Triblobium spp. (Coleoptera) and the true bug Triatoma infestans (Heteroptera) use only ommochromes (Moraes et al ., ; Sethuraman and O'brochta, ; Nathaniel et al ., ). White is a central protein involved in the eye‐pigmentation pathway, and forms dimers with either of the Brown or Scarlet proteins.…”

karmoisin and cardinal ortholog genes participate in the ommochrome synthesis of Nilaparvata lugens (Hemiptera: Delphacidae)

“…Except the wild‐type brown eye, red‐eye color mutation phenotype can also be observed (Seo et al ., ; Liu et al ., ). Moreover, red eye mutation phenotype is also present in other Hemipterans, such as Sogatella furcifera , Laodelphax striatellus (Wang et al ., ) and several bugs (Shimizu & Kawasaki, ; Pires et al ., ; Snodgrass, ; Moraes et al ., ; Allen, ; Hull et al ., ). However, the mutation mechanisms of these insects are still unknown, limited by the lack of clarity regarding the eye pigment synthesis pathway.…”

A comparative study of fat body morphology in five mosquito species

“…Excessive levels of tryptophan are harmful and ommochromes, which can function as eye and integument pigments, as well as excretory products, serve to eliminate excess tryptophan (Tearle 1991). Ommochromes also provide pigmentation for various insect tissues during development (for review see Oxford & Gillespie 1998, Moraes et al 2005, Insausti & Casas 2009. It is known that fat body cells are important for detoxification and homeostasis of insects by recruiting and storing toxic substances from the haemolymph.…”