| The morphological differences between bisexual parents of Paa spinosa were studied by cluster analysis, principal component analysis, and discriminant analysis. 84 males and females respectively of 3-year-old mature individuals were randomly sampled from a cohort of artificial cultured single species. 15 morphological traits including Internasal length(INS), Interorbital length(IS), Eye diameter(ED), Snout length(SL), Head length(HL), Head width(HW), Shoulder width(SW), Fore-limb length(FLL), Fore-arm length(FAL), Forefoot length(FFL), Hind-limb length(HLL), Hind foot length(HFL), Shoulder-to-anus length(SAL), Snout-urostyle length(SUL) and Volume of body(BV) were measured. Sexual differences reflected in the effect of morphological traits on body weight(BW) and net body weigh(NW) weight of Paa Spinosa was studied by multivariate regression analysis. The results indicated that:(1)among the related 20 biological traits and 25 morphological indexes,there were significant differences in 17 biological traits and 16 morphological indexes between each gender(P<0.05). And the Euclidean distance which is based on the mean of morphological indexes is 0.305(P<0.01). After being analyzed by principal component analysis, the accumulative variance percentage of the five principal components whoes eigenvalues were all larger than 1 was 80.841%. And the first principal component could be regarded as energy metabolism factor related to the configuration of organ quality, and second the principal component could be food deglutition factor related to the oral cavity space size as a representative of head width and snout length,and the last three principal components could be predation function factor related to the ability of hunting, jumping and holding as a representative ratio of foot and leg and interorbital space. Through discriminant analysis,the six principal components,L1(foreleg length/ fore limb length), L5(snout length/shoulder breadth), L7(interorbital space/head width), W2(stomach weight/heart weight), W4(lung weight/heart weight), W6(gonad weight/heart weight),were served as independent variables to establish Fisher classification function equations which could clearly distinguish the bisexual perent of Paa spinosa.The result shows that the accurate discriminant rate of P1 and P2 were 84.52%, 83.53% and 83.33%, 84.34% respectively, and the synthetic discriminant rate is 83.93%.(4) Except IS, ED and SL, the other 12 morphological measured values, BW and NW of males were significant higher than those of females(P<0.05).(5) All the correlation coefficients between each morphological trait and BW, and NW, were at extremely significant level(P<0.01) in males. And the traits that showed no significant correlation with BW and NW of females were respectively ED, SL, FFL and ED, SL, HL.(6) With the path analysis, BV was the decisive variable to affect the BW and NW. The correlation indexes of the reserved morphological traits on BW and NW in males were 0.952 and 0.939, respectively. The corresponding direct effect on BW and NW indexes were, in decreasing order, BV and SW. Meanwhile, the correlation indexes of the reserved morphological traits on BW and NW in females were 0.922 and 0.860, respectively. The direct effect of the former were, in decreasing order, BV, HLL and HL. And the latter were BV and HLL.(7) Multiple regression equations was used to estimate BW and NW. The equations for BW and NW of males were BW(?)= 0.894BV+0.750 SW-16.481 and WN(?)= 0.727BV+0.600 SW-10.184, respectively. Similarly, equations for females were BW(?)=0.841BV+0.220HLL+0.344HL-20.950 and WN(?)=0.543 BV+0.346HLL-24.916, respectively. |
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