Mikihiko Kumashiro

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We have investigated the morphology and physiology of the genitalia of the male cricket to establish a basis for neuroethological study of its reproductive behaviour. First, the structure of the phallic complex, including the dorsal pouch, guiding rod, epiphallus, ventral lobes and median pouch, are described, as are the muscles, cuticle, membranes and(More)
To understand the neural mechanisms of reproductive behaviour in the male cricket, we identified motor neurones innervating the muscles in each genital organ by backfilling with cobalt/nickel and recording their extracellular spike activity from nerve bundles of the terminal abdominal ganglion during tethered copulation and spermatophore formation. During(More)
The reproductive cycle of the male cricket consists of the mating stage and the sexually refractory stage. The latter is further divided into the first refractory stage (RS1) from spermatophore extrusion in copulation to spermatophore preparation after copulation, and the second refractory stage (RS2) from spermatophore preparation to recommencement of a(More)
The male and female genitalia are finely designed to match each other for copulation in the cricket Gryllus bimaculatus. Copulatory acts of the male, stereotyped and time-fixed, are elicited by stimulation of mechanoreceptors on particular regions of the abdomen, cerci and genitalia. Sequential execution of each motor act proceeds as a chain reaction in(More)
The genitalia of the male cricket, Gryllus bimaculatus, is automatically maintained. It is carried out by spontaneous undulation of the scaled membrane consisting of the genital chamber floor. To understand the mechanism of that movement, part of the membrane was cut out and examined in vitro with biogenic amines, and the spike activity of neurons(More)
We found that the genitalia of the male cricket Gryllus bimaculatus are equipped with an autocleaning system. The cricket keeps its genitalia clean by removing foreign matter and endogenous waste. Morphological study showed that the membrane complex consists of a median pouch and a genital chamber floor covered by small scales, each of which has a base of(More)
Three types of genital movement, their neural controls, and functional roles were investigated to gain a better understanding of the mechanism underlying autocleaning in the male cricket. The membrane complex consisting of the median pouch and genital chamber floor shows peculiar undulation that is composed of two types of movements: a right-left large(More)
Auto-spermatophore extrusion is a kind of spermatophore extrusion without genital coupling in the male cricket. It rarely occurred in intact males paired with a female, while it frequently occurred in all the males with the connectives cut under restraint and dissection. The time interval (SPaSE) between spermatophore preparation and auto-spermatophore(More)
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