Bellowing Mechanism And Mating Success Of Reproductive Strategies In Pere David’s Deer Stag

Recent years, many studies on behavioral ecology and conservation biology have been conducted on Pere David’s deer. Based on these researches, we combine the behavior observation, acoustical analysis and paternity test to study the formation process, the modulation mechanism and ecology significance of reproductive behavior in captivity. By using the ecology theory and molecular biology methods, we try to understand the evolution fitness of different reproductive strategies in Pere David’s deer and discuss the possible mechanisms of milu in captivity maintaining the genetic variety through behavior tactics, and then explore the theoretical basis of behavioral ecology for the management and development of ex-situ conservation population. The main findings were as follows:1. Acoustic traits, dominance rank and reproductive strategy.We classified stags in rut into three ranks:Harem Master, Challenger and Bachelor. The reproductive behavior and dominance rank of males were observed and recorded. We also recorded the bellowing sound of stags and measured the recording distance between observer and stags simultaneously. Through the acoustical analysis, we find there are two call types in milu deer, the common roar and chasing bark. The common roar is observed in all three ranks, while the chasing bark is mainly observed in Harem Master and Challenger. Moreover, the acoustical structure of common roar was more variable than chasing bark.Further statistical analysis shows acoustical difference among three dominance ranks and between two call types. The call duration differs insignificantly among three dominance ranks. It may result from the sacrifices of other physical-constrained acoustical features in subordinates, like the calling rate, which in order to be consistent with dominant males in call duration. In addition, the significantly increased call duration of chasing bark in Harem Master proved that this call type maybe critical in male competition. Because of the close relationship between formant frequency and dominance rank, we infer that the formant frequency which represents the inherent characteristics of callers plays more important role in male competition than the fundamental frequency which represents more about the dynamic characteristics of individual. Furthermore, the significant difference among three ranks confirms the vocal intensity to be effective in signaling the competitive ability of male callers.2. Relationship between reproductive strategy and reproductive success.Through the behavior observation of male deer in rut, we choose 20 adult males to collect feces sample and recorded their dominance rank and reproductive strategy. In the second year, we captured new born fawns and collected the ear tissue sample. Then we extracted the DNA from both samples to conduct the paternity test between adult males and new born fawns. Results show that, the extract rate of DNA in feces samples is lower than the extract rate of DNA in ear tissue samples. Second,11 microsatellite loci are found acceptable for the paternity test through the screening of 31 alternative microsatellite loci from former studies. Agree with literatures, the average alleles of this suit of markers are 2-4. Combining 10 markers,43% of the new born fawns are assigned to the only father. Average paternity exclusive rate reaches 86.01% and the offspring amount of Harem Master is 1.3. times larger than the offspring amount of Challenger. Additionally,57% of new born fawns fail in assignment. The certain 10 pairs show that the average offspring number of Harem master is more than the average offspring number of Challenger. The uncertain pairs still in some level reveal that the offspring number of earlier Harem Master exceeds the offspring number of later Harem Master. The paternity results showed that males from both statuses had offspring. Comparing the offspring number of candidate father from two statuses, we infer that the mating success of Master, who holds the harem, is greater than the mating success of Challenger, who sneaks to mate with females. For the first time, we prove that the difference of mating success may exist between earlier Master and late Master.