Rough eyes of the Northeast-Asian wood white, Leptidea amurensis

The Northeast-Asian Wood White Leptidea amurensis (Lepidoptera, Pieridae) belongs to Dismorphiinae, a subfamily of the family Pieridae. We here studied the structure of the compound eye in this species through a combination of anatomy, molecular biology and intracellular electrophysiology, with a particular focus on the evolution of butterfly eyes. We found that their eyes consist of three types of ommatidia, with a basic set of one short, one middle and one long wavelength-absorbing visual pigment. The spectral sensitivities of the photoreceptors are rather simple, and peak in the ultraviolet, blue and green wavelength regions. The ommatidia have neither perirhabdomal nor fluorescent pigments, which modulate photoreceptor spectral sensitivities in a number of other butterfly species. These features are primitive, but the eyes of Leptidea exhibit another unique feature: the rough appearance of the ventral two-thirds of the eye. The roughness is due to the irregular distribution of facets of two distinct sizes. As this phenomenon exists only in males, it may represent a newly evolved sex-related feature

Eyes with basic dorsal and specific ventral regions in the glacial Apollo, Parnassius glacialis (Papilionidae)

Recent studies on butterflies have indicated that their colour vision system is almost species specific. To address the question of how this remarkable diversity evolved, we investigated the eyes of the glacial Apollo, Parnassius glacialis, a living fossil species belonging to the family Papilionidae. We identified four opsins in the Parnassius eyes – an ultraviolet- (PgUV), a blue- (PgB), and two long wavelength (PgL2, PgL3)-absorbing types – and localized their mRNAs within the retina. We thus found ommatidial heterogeneity and a clear dorso-ventral regionalization of the eye. The dorsal region consists of three basic types of ommatidia that are similar to those found in other insects, indicating that this dorsal region retains the ancestral state. In the ventral region, we identified two novel phenomena: co-expression of the opsins of the UV- and B-absorbing type in a subset of photoreceptors, and subfunctionalization of long-wavelength receptors in the distal tier as a result of differential expression of the PgL2 and PgL3 mRNAs. Interestingly, butterflies from the closely related genus Papilio (Papilionidae) have at least three long-wavelength opsins, L1–L3. The present study indicates that the duplication of L2 and L3 occurred before the Papilio lineage diverged from the rest, whereas L1 was produced from L3 in the Papilio lineage

Evolution of color vision in pierid butterflies: Blue opsin duplication, ommatidial heterogeneity and eye regionalization in Colias erate

This paper documents the molecular organization of the eye of the Eastern Pale Clouded Yellow butterfly, Colias erate (Pieridae). We cloned four cDNAs encoding visual pigment opsins, corresponding to one ultraviolet, two blue and one long wavelength-absorbing visual pigments. Duplication of the blue visual pigment class occurs also in another pierid species, Pieris rapae, suggesting that blue duplication is a general feature in the family Pieridae. We localized the opsin mRNAs in the Colias retina by in situ hybridization. Among the nine photoreceptor cells in an ommatidium, R1-9, we found that R3-8 expressed the long wavelength class mRNA in all ommatidia. R1 and R2 expressed mRNAs of the short wavelength opsins in three fixed combinations, corresponding to three types of ommatidia. While the duplicated blue opsins in Pieris are separately expressed in two subsets of R1-2 photoreceptors, one blue sensitive and another violet sensitive, those of Colias appear to be always coexpressed

Coexpression of three middle wavelength-absorbing visual pigments in sexually dimorphic photoreceptors of the butterfly Colias erate

The tiered ommatidia of the Eastern Pale Clouded yellow butterfly, Colias erate, contain nine photoreceptor cells, four of which contribute their rhabdomeral microvilli to the distal tier of the rhabdom. We analyzed the visual pigments and spectral sensitivities of these distal photoreceptors in both sexes of Colias erate. A subset of photoreceptor cells expresses a newly discovered middle wavelength-absorbing opsin, Colias erate Blue (CeB), in addition to two previously described middle wavelength-absorbing opsins, CeV1 and CeV2. The other photoreceptors either coexpress CeV1 and CeV2, or exclusively express a short wavelength-absorbing opsin, CeUV, or a long wavelength-absorbing opsin, CeL. Males and females have the same visual pigment expression patterns, but the photoreceptor spectral sensitivities are sexually dimorphic. The photoreceptors coexpressing three middle wavelength-absorbing opsins are broad-blue receptors in males, but in females they are narrow-blue receptors. Those with CeV1 and CeV2 are violet receptors in females, while they are shouldered-blue receptors in males. The sexual dimorphism in spectral sensitivity is caused by a sex-specific distribution of fluorescent pigment that functions as a spectral filter

Pseudo Extension in Default Reasoning and Belief Revision by Model Inference

Lecture Notes in Artificial Intelligence 383,27-37, 1989This paper is concerlled with extension and belief revision in Reiter\u27s default reasoning, First we introduce a new notion of pseudo extension which is successively constructed from a given default theory. We show that the set of pseudo extensions contains the set of extensions, so that we can get some reasollable candidates of extension in a constructive way. This should be a first step towards computerization of the default reasoning. We also discuss the belief revision problem from the viewpoint of Shapiro\u27s inductive inference of models

PSEUDO EXTENSION AND BELIEF REVISION IN DEFAULT REASONING

This paper is concerned with the extension and the belief revision in Reiter\u27s default reasoning. First we introduce a new notion of pseudo extension which is successively constructed from a given default theory. We show that the set of pseudo extensions contains the set of extensions, so that we can get some reasonable candidates of extension in a constructive way. This should be a first step towards computerization of the default reasoning. We also discuss the belief revision problem from the viewpoint of Shapiro\u27s inductive inference of models

Pseudo Extension in Default Reasoning and Belief Revision by Model Inference

This paper is concerlled with extension and belief revision in Reiter's default reasoning, First we introduce a new notion of pseudo extension which is successively constructed from a given default theory. We show that the set of pseudo extensions contains the set of extensions, so that we can get some reasollable candidates of extension in a constructive way. This should be a first step towards computerization of the default reasoning. We also discuss the belief revision problem from the viewpoint of Shapiro's inductive inference of models.Lecture Notes in Artificial Intelligence 383,27-37, 198

PSEUDO EXTENSION AND BELIEF REVISION IN DEFAULT REASONING

This paper is concerned with the extension and the belief revision in Reiter's default reasoning. First we introduce a new notion of pseudo extension which is successively constructed from a given default theory. We show that the set of pseudo extensions contains the set of extensions, so that we can get some reasonable candidates of extension in a constructive way. This should be a first step towards computerization of the default reasoning. We also discuss the belief revision problem from the viewpoint of Shapiro's inductive inference of models