Role of male accessory glands in spermatodesm reorganization in Orthoptera Tettigonioidea.

A preliminary examination of the spermatodesms of Orthoptera Tettigonioidea revealed a structure that is similar in individuals of the same sex but very different in specimens of opposite sex. This reorganization would seem to take place inside the spermatophore during transit from the male to female genital tracts. The results of incubating spermatodesms with the secretions of glandular extract (GE) obtained from male accessory glands, known to be involved in forming the spermatophore wall, revealed changes in the spermatodesm 'cap' that are comparable to those occurring in vivo. Moreover, incubation of spermatodesms with the extracts obtained separately from tubules of the 1st and 2nd orders (GE1, GE2) established that GE2 alone modifies the spermatodesms, thus excluding the possible implication of 1st order tubules in the rearrangement process. In conclusion, data from incubations of spermatodesms with the single fractions obtained by submitting GE2 to gel-filtration FPLC show that only the peak 4 maintains intact the biological activity of GE2, SDS-PAGE analysis of the fraction corresponding to peak 4 revealed a greater protein content of 29 kD, which also appears to a lesser degree in fraction 3. This material is responsible for a partial dismantling of the 'cap' in the incubated spermatodesms.

Structure of spermatodesms of Orthoptera Tettigonioidea.

Examination of spermatodesms collected from the male and female genital tracts of numerous Orthoptera Tettigonioidea revealed an overall morphological and ultrastructural organization that is generally similar in individuals of the same sex but considerably different between males and females of even the same species. In the male genital tracts each spermatodesm is composed of a limited number of spermatozoa whose nuclei and acrosomes are covered by a mucous cap. The spermatozoa inside each bundle are mainly arranged in parallel rows and are always distinctly separate. The number of spermatozoa per spermatodesm may vary within the same individual although it does not seem to exceed a maximum value that we could only determine exactly in Tettigoniidae species. The most characteristic feature of spermatozoa of all the species examined is a conspicuous elongation of the plasma membrane in the acrosomal region that is not present in the female genital tracts. In addition, spermatodesms from females are composed of highly numerous tightly packed spermatozoa that are linked together via the acrosomal region. This characteristic of spermatodesms, never previously reported in other insect species, would involve their reorganization during transfer from the male to the female genital tracts and would seem to take place in the spermatophore. The probable role of spermatodesms in the reproductive physiology of Tettigonioidea might be related to the degree of maturity of the sex cells transferred to the female; the reorganization of the spermatozoa out of the male genital tracts seems to support this hypothesis.

Ultrastructural and histochemical characteristics of the lateral oviducts of Baculum thaii Haus. (Phasm.).

The wall of the lateral oviducts of baculum thaii is composed of a monolayered epithelium, lacking a cuticular intima, which lies on a sheath of striated muscular fibres. Untreated oviductal specimens exhibit two distinct regions. The anterior region, into which the various ovarioles emerge, is opalescent. The posterior region is more dilated and darker in colour. On the basis of the ultrastructural characteristics of the epithelial cells, four successive zones are definable for each oviduct. The first two zones comprise the most anterior oviductal area while the third and fourth comprise the posterior region. In zone 1 only is the oviductal wall composed of a single cell type. In addition, differences in structural organization between mated and virgin females were observed in this zone alone. In the three remaining zones, two distinct cell types were distinguishable according to two models of fundamental organization: cells having numerous apical microvilli and dome-shaped cells. The results of histochemical analyses established that the abundant secretory product elaborated by the epithelial cells is rich in both proteins and predominantly acidic mucosubstances. The histochemical characteristics of the secretory product differentiate significantly not only between the four zones in the same individual but also when the corresponding zones are compared in the mated and virgin females.