杂交白头叶猴F1代及其后代性状和行为跟踪观察

Observations on the Hybrid F1 of Trachypthecus leucocephalus and T. francioisi and Its Offspring

通过对白头叶猴与黑叶猴杂交所得的雌杂白头叶猴F1代(F1f)的性状及行为观察,以及F1代与黑叶猴进行回交繁殖出来的后代Be1、Be2、Be3和Be4的性状表现及生长发育的长期观察,结果表明:杂交白头叶猴及其回交代的性状、形态特征与黑叶猴十分相似,黑毛性状占绝对的优势。白头叶猴所拥有的性状在杂白头叶猴及其后代中几乎不表现,仅是在生长中存在部分印记,在发育过程中的颜色转变时间延长,毛色转变也有痕迹的现象。这说明白头叶猴的基因控制在回交代中只起到辅助作用,但总的以黑叶猴的基因控制为主。白头叶猴回交代个体弱仔率比例高达50%,高于同期的黑叶猴弱仔率,后者一般为10%—20%,呈现出远交衰退迹象。杂交代F1在繁殖行为及对后代的哺育投资上与黑叶猴无明显区别;回交代的生长发育和行为发育与黑叶猴的行为有趋同性。综合上述特征,结合杂交白头叶猴F1f的连续繁殖成功,可以断定白头叶猴不是一个独立种,而是黑叶猴的一个亚种。

The characteristics and behaviours of F1f （the female hybrid of Trachypithecus leucocephalus and T.francoisi） and its backcross offspring （Be1, Be2, Be3 and Be4） were extensively observed. The results showed that the hybrid F1f and its offspring had similar characteristics with T.francoisi. Besides the black hair was an overwhelmingly dominant character, the changing of their hair colour, the breeding behaviour of hybridized F1, and the growing process and behaviours of the hybrid F1f offspring resembled T.francoisi. However the feature of T. leucocephalus was nearly not present in the hybrid F1 and its offspring, excepting that in the development process the time for their hair colour change was longer and during their growth there existed imprinting phenomenon of T. leucocephalus. Therefore it can be inferred that the gene control of T. leucocephalus only played a supporting role and T.francoisi＇s gene dominated in the hybrid F1f and their offspring. The percent of weak infants for backcross langurs reaching 50%, which was higher than that of the general 10%-20% of T.francoisi, suggested a sign of outbreeding depression. Based on our observation that the hybrid F1f was able to reproduce its offspring successfully we can make a conclusion that T. leucocephalus should be considered as a subspecies of T.francoisi instead of an independent species.