Morphogenesis of the photoreceptive site and development of the electrical responses in the butterfly genital photoreceptors during the pupal period.
This paper describes the process of morphogenesis of the photoreceptive site of the butterfly genital photoreceptors. Associated development of the electrical responses is also described. The photoreceptor is a sensory neuron whose cell body is located in the genitalia and has a photoreceptive site of the phaosome-type. This consists of the distal processes and the tubular membranes, which protrude from the tip of distal processes. Phaosome morphogenesis was studied using electron microscopy. The results indicate that morphogenesis occurs in the latter half of the pupal period and that the process is divided into five phases. First, the tubular membranes appear as small membrane protrusions (phase I). The short tubular membranes emerge from several portions of the cell body forming several membrane clusters (phase II). The clusters then collect to form a small phaosome. Short distal processes become evident (phase III). The phaosome volume increases, mainly due to the extensive elongation and bifurcation of both tubular membranes and distal processes (phase IV). Phase V achieves final adult morphology. The photoreceptors of phase II are already able to produce spikes in response to light stimulation, although the sensitivity was about one tenth of the adult. The sensitivity increase occurred in parallel with the increase in the phaosome volume.
Miyako
Y
Y
Department of Biology, Yokohama City University, Japan.
Arikawa
K
K
Eguchi
E
E
D000818:Animals; D002080:Butterflies / Q000254:growth & development*; D005071:Evoked Potentials / Q000502:physiology; D005260:Female; D005836:Genitalia, Female / Q000166:cytology / Q000254:growth & development*; D008027:Light; D009024:Morphogenesis; D009474:Neurons / Q000502:physiology*; D015388:Organelles; D017956:Photoreceptor Cells, Invertebrate / Q000166:cytology / Q000254:growth & development*; D011679:Pupa / Q000254:growth & development