The visual pigment chromophores in the retina of insect compound eyes, with special reference to the Coleoptera

A new survey, by HPLC, of the visual pigment chromophores in the compound eye of Japanese insects was made during the Summer and Autumn of 1988. The results largely conformed to those of previous studies (in Europe, Japan and the U.S.A.), except for the discovery of several coleopterans unusual in containing both retinal (A₁) and 3-hydroxyretinal (A₃). The chromophores of five coleopteran families are described for the first time: the Gyrinidae, Hydrophilidae and Lampyridae contain both A₁ and A₃: while in the Lucanidae and Melandryidae only A₁ was detected. Of the Family Cerambycidae (the only insect family so far discovered to contain members with different chromophore types), one of the two major subfamilies not previously investigated, the Lepturinae, yielded only A₁. Newly-tested species from the Prioninae conformed to earlier findings (A₁ only). Additional data (Vogt, previously unpublished) suggest that the Cantharidae, Cicindelidae, Dermestidae and Tenebrionidae also utilize only A₁. The distribution of A₁ and A₃ among the insects is discussed in terms of phylogeny, diet, and the photic environment. The coleopterans utilizing both A₁ and A₃ are widely separated, phylogenetically, but most are carnivorous and associated with an aquatic environment. The co-incidence of these features also in the Odonata, which generally utilize both A₁ and A₃, suggests that chromophore content in both groups may well be environmentally related. These findings are compared with the seasonal and environment-related occurrence of A₁ and A₂ (3-dehydroretinal) reported for fishes, amphibians and crustaceans. The data now accumulated for compound eye chromophore content of the Insecta are listed. Included are first mentions of the Dermaptera (the earwig Anisolabis maritima) and Megaloptera (Sialis lutaria), which contain only A₁. Exceptions to the previously apparent, general phylogenetic trends are now known in the Orders Coleoptera, Diptera, Neuroptera and Odonata.