The number of cells and the size of the cells in the male accessory gland, the quantity of accessory gland proteins, and their effects on fitness in males of different ages were studied in Drosophila bipectinata Duda (Diptera: Drosophilidae). Male age was significantly positively correlated with the size of accessory gland, the number of main cells of the accessory gland, the quantity of protein in unmated males, the duration of copulation, the transferred quantity of protein and sperm to the mated female, fecundity, and fertility, while male age was significantly negatively correlated with the size of main cell in the accessory gland and the quantity of protein in mated males. The size of the main cells was significantly positively correlated with the quantity of protein in unmated males but significantly negatively correlated with the size of the accessory gland and the number of main cells in the accessory gland. These results suggest that D. bipectinata young males, with their smaller size of their accessory glands and having fewer and larger main cells in their accessory glands, produced the least quantity of protein and transferred significantly less protein and sperm to the mated female than did middle and old age males. Thus, this study suggests that in D. bipectinata, male age affects the number of accessory gland cells and the quantity of protein in the accessory gland. The size and number of main cells in the accessory gland and the size of the accessory gland were related to the production of protein. Females who mated with old males obtained a fitness benefit.

For species in which mating is resource-independent and offspring do not receive parental care, theoretical models of age-based female mate preference predict that females should prefer to mate with older males as they have demonstrated ability to survive. Thus, females should obtain a fitness benefit from mating with older males. However, male aging is often associated with reductions in quantity of sperm. The adaptive significance of age-based mate choice is therefore unclear. Various hypotheses have made conflicting predictions concerning this issue, because published studies have not investigated the effect of age on accessory gland proteins and sperm traits. D. melanogaster exhibits resource-independent mating, and offspring do not receive parental care, making this an appropriate model for studying age-based mate choice. In the present study, we found that D. melanogaster females of all ages preferred to mate with the younger of two competing males. Young males performed significantly greater courtship attempts and females showed least rejection for the same than middle-aged and old males. Young males had small accessory glands that contained very few main cells that were larger than average. Nevertheless, compared with middle-aged or old males, the young males transferred greater quantities of accessory gland proteins and sperm to mated females. As a result, females that mated with young male produced more eggs and progeny than those that mated with older males. Furthermore, mating with young male reduced female's lifespan. These studies indicate that quantity of accessory gland proteins and sperm traits decreased with male age and females obtain direct fitness benefit from mating with preferred young males.

The accessory gland has a simple structure composed of a single layer of a cells surrounding a lumen that is in turn surrounded by a muscle sheath. It synthesizes a proteins, carbohydrates and lipids which are transferred at the time of mating between male to the mating female. In this study we have determined the number of cells, cell size and gland size in male Drosophila melanogaster, unmated male flies of 2-3 day old were used the exposed to three temperatures, cold(15°c), middle (22°c) and high(29°c) temperature. The results showed, cell size in cold temperature was smaller than middle and high temperature and between three temperatures results of ANOVA and correlation coefficient were significant, p value< 0.01 (cold>middle > high). Results of cell number in cold, middle and high temperature by ANOVA variation and correlation coefficient was significant, the mean value of cell number in high temperature more than low and middle temperature respectively (High> cold> middle). Regarding, gland size, the mean value also, in high temperature condition bigger than middle temperature. The results of ANOVA variation and correlation coefficient were significant. [Our main aim is to show the effect of temperature on the reproductive system, especially on the male accessory gland in Drosophila including, structure of gland of cell size and cell number, that changed when flies were exposed to different temperature].