Genitalic autogrooming in the male cricket,Gryllus bimaculatusDeGeer

Abstract

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 innervating muscle fibers of the membrane was analyzed. The esults indicated that the fragment of the membrane, which showed spontaneous twitching in saline, increased its frequency at 5-HT application. In contrast, mianserin (5-HT antagonist) decreased its occurence. Immunocytochemical study indicated that massive 5-HT-positive branchibgs of one main axon nnervated muscle fibers of the genital membrane. Centrally, one of the motoneurons backfilled with ucifer Yellow through the cut end of the nerve 9v of the terminal abdominal ganglion was determined 5-HT positive. These results suggested that the undulatory movement of the genital membrane for genitalic autogrooming is mediated by 5-HT.

Genital Autocleaning in the Male CricketGryllus bimaculatus(1): Structure and Function of the Genital Membrane

“…These should produce unidirectional driving force via the elastic nature of the spines of the scales on the membrane surface as we suggested (Fig. 12 in Kumashiro and Sakai, 2016). Thus, foreign susbtances on the membrane complex are smoothly conveyed to the lateral pouch on either side of the genital chamber.…”

“…10A-3, black arrow) by the tips of the scale spines, which function as latches (Fig. 12 in Kumashiro and Sakai, 2016).…”

“…The recent study in which axonal filling was performed at a more distal site of the same nerve branch revealed that there were four somata in the lateral part of the TAG (Kumashiro et al, 2008). Immunocytochemical study combined with retrograde and anterograde staining using Lucifer Yellow showed that the largest one of the four backfilled neuron somata was serotonergic, and that only one serotonergic axon extended collaterals over the membrane complex (Kumashiro et al, 2008). These results suggest that the neuron (mMP-2) with the largest spike and innervating muscle fibers is serotonergic.…”

“…First, somata of the efferent neurons, which were stained retrogradely from the cut end of the nerve 9v branch, were all found in the motoneuron cluster region (soma ventrally and dendrites dorsally) in the lateral part of the TAG (Kumashiro and Sakai, 2001b;Kumashiro et al, 2008), and the largest serotonergic neuron soma was also located in the same region (Kumashiro et al, 2008). Second, octopaminergic efferent neurons like dorsal unpaired median (DUM) neurons, which are not classified as motoneurons, but as modulatory neurons, innervate both visceral and skeletal muscles (Bräunig and Pflüger, 2001).…”

“…This system is indispensable for the production of a normal spermatophore (Kumashiro and Sakai, 2016). The genital membrane complex consisting of the median pouch and genital chamber floor is entirely covered by small scales and undulates rhythmically at a frequency of 0.16 Hz (Sakai and Kumashiro, 2004).…”