Behaviors,Sex Hormones And Sex Pheromones During Reproductive Period Of Captive Amur Tigers

The goal of this dissertation was to understand changes in behaviors,sex hormones,and pheromones during the reproductive period of captive Amur tigers by studying twenty captive Amur tigers(12 females,8males)from January 2015 to January 2017 at the Hengdaohezi Feline Breeding Center(FBC)in China.No.l Captive Amur tiger reproductive behaviorsWe collected behavioral data on six female and six male tigers with offsprings.We study identified obvious sexual solicitation by female Amur tigers.During the rutting periods,female tigers experienced on average 6.1(± 0.5 SD)sexual solicitations per day.Each male ejaculated on average 2.3(± 0.3 SD)times daily.Female sexual solicitations were on average 55.1%(±4.2%SD)successful and copulation was on average 50.8%(± 4.5%SD)successful.No more than one ejaculations happened within an hour by a single male.Amur tigers copulatory behavior matched Dewsbury's copulatory pattern No.11 which involves no locking with thrusting,multiple intromission,and a single ejaculation.No.2 Oestrus judgement according to urinary estradiol and testosteroneThe goal of this study was to evaluate whether urinary sex hormones(estradiol and testosterone)could be used to assess the reproductive status of Amur tiger.We measured urinary estradiol(E2)and testosterone(T)in six pregnant and six non-pregnant females as well as eight males,both during the rutting period and non-reproductive season.E2 was only measured in females.For pregnant and unpregnant females,E2 concentrations were both obviously higher during the rutting period than the non-reproductive season.T concentrations of male tigers with offsprings were also obviously higher during the rutting period than the non-reproductive season,but T concentrations of males with no offsprings were indistinguishable between rutting period and the non-reproductive season.E2 concentrations for every single female tigers and T concentrations for every single male tigers were were indistinguishable between rutting period and the non-reproductive season.The results suggested that both E2 concentrations of females and T concentrations of males rose after mating.However,urinary E2 and T can not be used to determine the reproductive status of a single Amur tiger.No.3 Amur tiger sex pheromones in rutting periodHere,we used gas chromatography-mass spectrophotometry(GC-MS)to study urinary sex pheromones during rutting and non-reproductive periods of female and male Amur tigers and to experimentally test the function of isolated pheromones in sexual behavior.We identified thirteen kinds of volatiles.Urinary phenol concentrations in male Amur tigers were significantly higher in the rutting period than in the non-reproductive period and the average relative phenol concentration was 3.33%(±1.38%SD)in the rutting period and 0.24%(±0.12%SD)in the non-reproductive period.Urinary benzeneethanamine concentrations in female tigers was significantly higher in the rutting period than in the non-reproductive period and the average relative abundance was 16.36%(±3.10%SD)in rutting period and 5.53%(±0.97%SD)in the non-reproductive period.Our behavioral experiments found that 2-phenethylamine induced more sexual behaviors obviously in males.Other volatile compounds exhibited sex differences between the rutting and non-reproductive periods.Our results suggested that urinary volatile compounds may act as reproductive pheromones in Amur tigers.In particular,benzeneethanamine was affirmed as a kind of pheromone by female to convey reproductive information to male while phenol may be used by males during the rutting period.No.4 Urinary progesterone as a proxy for early pregnancy detectionHere,we tested whether urinary progesterone could be used to detect pregnancy in captive Amur tigers.Using a radioimmunoassay(RIA),we analyzed progesterone in twelve captive female Amur tigers including six pregnant and six non-pregnant females during both their rutting periods and the four weeks after rutting.We found that progesterone was higher in pregnant females after the rutting period than for non-pregnant females.Urinary progesterone concentrations did not differ,however between the rutting and non-reproductive period for non-pregnant females.So we could judge whether female tiger pregnant according to progesterone levels after mating.