Influence of mating histories and age on female remating behaviour in a few closely related species of Drosophila nasuta subgroup.

Female remating with more than one male leads to coexistence of sperm from different males in the same female, thus creating a selection pressure on sperm. To understand the extent of divergence in the reproductive behaviour among closely related species, in the present study, the influence of first mating histories like mating latency, duration of copulation and age of flies have been analysed on female remating behaviour in closely related Drosophila nasuta subgroup species with varying levels of reproductive isolation. The time taken for the once mated females to remate varied from 7 days in D. s. sulfurigaster to 19 days in D. s. neonasuta after first mating. The female remating frequency varied from a minimum of 29% in D. s. neonasuta to a maximum of 95% in D. s. sulfurigaster. The younger flies, which had remating latency of three times less than aged flies, show 100% remating frequency. In addition, it was observed that the duration of copulation in the first mating influences the remating behaviour among the nasuta subgroup members. The results revealed that D. nasuta subgroup members despite being closely related differ in their reproductive behaviour.

Male accessory gland secretory protein polymorphism in natural populations of Drosophila nasuta nasuta and Drosophila sulfurigaster neonasuta.

Male accessory gland secretory protein polymorphism was analysed in natural populations of Drosophila nasuta nasuta and D. sulfurigaster neonasuta for the first time, using SDS-PAGE to score polymorphism of these proteins in 2788 individuals of D. n. nasuta and 2232 individuals of D. s. neonasuta from 12 different populations from southern India. A total of 25 and 18 variant protein phenotypes were identified in D. n. nasuta and D. s. neonasuta, respectively. Protein fractions of group III were more polymorphic than those from groups I and II. The results show that accessory gland secretory proteins show high levels of polymorphism, irrespective of species or habitat. Moreover, we have used the variation in the accessory gland proteins to assess the extent of divergence between the species and to infer their population structure. The study suggests that though both D. n. nasuta and D. s. neonasuta belong to the same subgroup, they differ in population structure, as far as accessory gland protein polymorphism is concerned.

Male accessory gland proteins in Drosophila: a multifaceted field [corrected].

Male accessory gland in Drosophila is a secretory tissue of the reproductive system. The proteins synthesized in the accessory gland are tissue specific, stage specific-seen only during the adult stage and sex specific in the sense of male limited expression. These secretions that form a component of the seminal fluid are transferred to the female at the time of copulation and play an important role in reproduction. In conjunction with sperm, these secretory proteins assure reproductive success by reducing the female's receptivity to mating and escalating the rate of egg laying. Some of these proteins are antibacterial in nature with a likely function of protecting the female's genital tract against microbial infection during/after mating. Most of the genes involved in the synthesis of accessory gland proteins are autosomal but a few are still X-linked. Their male specific expression is achieved at the time of sex determination. The level of expression of these genes is dose dependent and they follow Mendelian pattern of segregation. Further, majority of these proteins are rapidly evolving with high rates of non-synonymous substitutions. In this review, by considering the work carried out in different fields, we have tried to generate a comprehensive picture about the male accessory gland and the role of its proteins in the reproduction of Drosophila.

Male accessory gland secretions in hybrids of Drosophila nasuta nasuta and D. n. albomicans neither show luxuriance nor breakdown.

Male accessory gland secretions, which have a role to play in reproduction have been investigated. The number of cells that make up the gland, the quantity of secretions synthesized and the influence of these secretions on fecundity of the female have been studied in D. n. nasuta, D. n. albomicans and their F1 progeny. The results revealed that the hybrid males show a trend towards D. n. nasuta in the synthesis of male accessory gland proteins and the fecundity of the female is influenced more by its genetic constitution rather than the quantity of accessory gland secretions.

Male accessory gland secretory proteins in nasuta subgroup of Drosophila: nature and SDS-PAGE patterns.

Male accessory gland secretory proteins in seven members of Drosophila nasuta subgroup were analyzed by SDS-PAGE in combination with different staining techniques such as CBB-R250, Silver, PAS, PAS-silver and zinc-imidazole reverse staining. Based on coomassie blue patterns the protein fractions could be classified in to 3 major groups namely group I, group II as well as group III; with high molecular weight fractions falling into group I and low molecular weight fractions into group III. All the three groups of fractions are post-translationally modified by way of glycosylation and group III fractions are found to be highly glycosylated. Fractions of groups I and II when localized with silver stain and group III fractions when localized with PAS-silver stain appear yellow; suggesting that they are sialoglycoproteins. A 40 kD fraction of group II shows differential staining property with zinc-imidazole stain in closely related species namely D. n. nasuta and D. n. albomicans. Analysis of this protein fraction in F1 males of an interspecific cross revealed that it is synthesized by X-chromosomal gene.

Quantitative and qualitative analysis of accessory gland secretory proteins in a few species of Drosophila immigrans group.

Quantitative and qualitative analysis of accessory gland proteins in four species of D. immigrans group has been made. Quantitative estimation of these proteins during development of the adult male revealed that there is a gradual increase in the quantity of secretions up to 7 days. The secretions constitute 72, 70, 50 and 54.2% in D.n. nasuta, D.s. neonasuta, D. rubida and D. pararubida respectively. Mating experiments showed that more than 1/3 of this stored secretory protein is transferred into the female reproductive tract during first mating. SDS-PAGE analysis of the accessory gland secretions revealed remarkable simplicity in their patterns, including the absence of age dependent alterations. In all the 4 species analysed, only the low mol. wt. fractions are not glycosylated. It was further observed that the extent of similarity between D.n. nasuta and D.s. neonasuta is greater than between D. rubida and D. pararubida.