The small size and the lack of recombination set the fourth chromosome of Drosophila melanogaster apart from the other chromosomes. I have shown that the Minute gene on chromosome 4, earlier named Minute-4, encodes the ribosomal protein RpS3A. Two Pax6 genes, eyeless (ey) and twin of eyeless (toy) are also located on chromosome 4. Pax6 genes are important in head and eye development in both mammals and Drosophila. I have focused much of the study on ey and toy. The first mutant of toy that was characterized showed a headless phenotype. This indicates that Toy is important for the development of both the eye and antennal discs. The phenotype of the null mutation in toy is temperature sensitive due to that transcription of ey is temperature dependent in the eye-antennal primordium in absence of Toy. This temperature dependence was used to find out that the phenocritical period for ey in the adult head development is during embryonic stage 12-16 when ey first is expressed in the eye-antennal primordium. I also conclude that ey is activated by Toy in the eye-antennal primordium. The strong eyD mutation was molecularly characterized and it was finally settled that it is an allele in the ey locus. I also show that eyD homozygotes have a headless phenotype, much stronger than the earlier ey mutations.

In the early 20thcentury, a “crisis of ocularcentrism” arose in philosophy, replacing the Cartesian epistemological notion of a disembodied mind inspecting the object-world from the outside with an ontological and phenomenological approach to vision and being, embedding humans corporeally in a world exceeding their perceptual horizon (Jay 94). In response, modernist artists abandoned realist and naturalist techniques, rejecting mimetic representation, and experimented with new artistic forms, trying to account for the new complexity of life.  In this context, Virginia Woolf wrote her novel The Waves (1931), “an abstract mystical eyeless book” (DIII 203). Despite countless studies on The Waves and vision, its “eyelessness” has never been thoroughly examined before. Since Woolf considered vision and being to be inherently embodied and communal and longed for capturing moments of being, this thesis proposes to unlock Woolf’s eyeless writing in The Waves through Maurice Merleau-Ponty’s late corporeal phenomenology. Alongside his concepts of the flesh and chiasm, this thesis claims that eyeless writing is Woolf’s method to go beyond vision in order to reveal the inherent corporeal interconnectedness of all beings in a hidden, visually imperceptible pattern—the eyeless flesh of the world—by creating a narrative that is eyeless in several ways. It is at once eye- and I-less due to lacking a single focalising point and denoting an anonymous visibility enveloping all beings. Rather than being structured by a narrative eye/I, it is governed by the characters’ bodies and their chiasmatic relations with the world. On this basis, emphasising the carnal adherence of all human and non-human beings, their eyeless kinship thus comes to light, creating a nonanthropocentric conception of Being-in-and-of-the-world. In this sense, The Waves uncovers that since the Wesen (essence) of Being lies in the common, visually imperceptible flesh, it can only be reached eyelessly, via the body.

This research explores the capacity for functional photoreception in larvae of the mountain pine beetle (Dendroctonus ponderosae), an extremely important forest pest insect that is well adapted for development beneath the bark of pine trees. Phototaxis tests, gene expression analysis and development experiments were integrated to assess mountain pine beetle larvae for light sensitivity. When presented with a phototaxis choice test, larvae preferred dark over light microhabitats, revealing that larvae sense and respond behaviourally to light. Long wavelength opsin transcription was identified in all life stages, including eggs and larvae, suggesting that D. ponderosae possesses extraretinal photosensitive capabilities across its life cycle. The long wavelength opsin could function in phototaxis or the development phenology of immature beetles, while the ultraviolet opsin, only found to be expressed in pupae and adults, is likely to function in dispersal via the compound eyes. Results from two development experiments reveal an effect of photoperiod treatment on beetle development rate when reared from the egg stage, but not when reared from mature larvae, indicating that a critical photosensitive life stage(s) must occur in D. ponderosae prior to the third larval instar. An effect of photoperiod on adult emergence rates, however, appears to be independent of larval rearing conditions. The discovery of opsin expression and negative phototaxis in eyeless mountain pine beetle larvae, in addition to an effect of photoperiod on immature development and adult emergence rates, suggest that light and photoperiodism likely function in survival and life cycle coordination in this species. / Graduate / 2018-10-17