Mikihiko Kumashiro

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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)
In our companion paper (Kumashiro and Sakai, 2001), we characterized the structure and function of the genitalia in the male cricket and established the sequence of motor actions during copulation and spermatophore formation. To understand the mechanisms of male reproductive behaviour more fully, recordings of neural activity in the nerve innervating the(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)
Insects groom almost all parts of the body surface with their legs and mouth parts. However, some body regions are difficult to reach and keep clean. One is the genital chamber located in the last abdominal segment in males which houses the phallic complex for copulation and production of the spermatophore. In the male cricket, foreign substances can enter(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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