| The life history characteristics of animal species(includes individual morphological characteristics,growth and development,and reproduction)are easily affected by various environmental factors,and some characteristics often exist variations within population.In this thesis,I investigated the effects of environmental factors on embryo development,growth and development,social behavior and locomotor performance as well as the effects of different water levels on the phenotype and physiology of Rana zhenhaiensis larva.Moreover,I recorded and analyzed individual variation in advertisement calls of adult male Xenophrys boettgeri during its breeding season.The main results are shown as follows:1 Effects of embryos incubation alone on growth,development,social behavior and locomotor performance of Rana zhenhaiensis tadpolesEmbryo-clustering incubation plays an important role of anti-predation,maintaining temperature balance between embryos and promoting hatching synchrony for anuran animals.In this study,we investigated the effects of incubation condition(embryo incubated in single and group)on growth,development,social behavior and locomotor performance of Rana zhenhaiensis tadpoles under laboratory conditions.Our results showed that both body length and Gosner development stage of single-embryo treatment were significantly larger than those of group-embryo treatment.The results of ACNOVA(with body length as the covariate)analysis showed that both body width and body mass in group-embryo treatment were significantly lower than those of single-embryo treatment.For tadpole activity behavior,the occurrence frequency in the upper and middle water layers in single-embryo treatments were significantly less than those of group-embryo treatment,while it was significantly larger in single-embryo treatments than that of group-embryo treatment in the lower water layers.The proportions of area occupied by tadpoles,the nearest neighbor distance and the distance among individuals in single-embryo treatment were all significantly larger than those of group-embryo treatment,but the frequency contacted between pairwise tadpoles was significantly lower than those of group-embryo treatment.As for locomotor performance,we found activity duration and activity frequency in single-embryo treatment were significantly lower than those of group-embryo treatment.These findings should provide some valuable reference data for early growth and development of Rana zhenhaiensis as well as other anuran species.2 Phenotypic and physiological responses of Rana zhenhaiensis tadpoles to pond desiccationIn this study,we investigated the effects of pond drying on the phenotypic characteristics in both growth and development,as well as the dynamic changes of anti-oxidase activity,amylase activity and malondialdehyde content in Rana zhenhaiensis tadpoles under laboratory conditions.The results of One-way ANOVA showed that there were no significant differences on their snout-vent length(SVL)between low water level treatment and high water level treatment,but the Gosner development stage in low water level treatment was significantly higher than that of high water level treatment.The results of ANCOVA(with body length as the covariate)analysis showed that both body width and body mass in low water level treatment were significantly lower than those of high water level treatment.The survival rate in low water level treatment(88%)was significantly lower than that of high water level treatment(98%).Rana zhenhaiensis tadpoles produced serial oxidative stress via pond desiccation.SOD,CAT and GPx in low water treatment were significantly higher than those of high water level treatment,while the malondialdehyde(MDA)content was no significant difference between the two treatments.But AMS in low water level treatment was significantly lower than that of high water level treatment.All in above,we predicted that pond desiccation could accelerate development rate,decrease digestive enzyme activity,reduce body size and increase the death rate and antioxidant enzyme activity of R.zhenhaiensis tadpoles.Therefore,tadpoles can exhibit/regulate some phenotype and physiological responses to pond desiccation,but not result in oxidative damage.3 Individual variation in advertisement calls of pale-shouldered horned toad,Xenophrys boettgeriDuring the breeding season the characteristics of a male anurans’ call will play an important role in its mating success.In this study,we recorded and analyzed the advertisement calls of pale-shouldered horned toad,Xenophrys boettgeri from the field during its breeding season.The results showed that several acoustic parameters were significantly correlated with morphological features and air temperature.Most acoustic parameters(NN,CD,CIT,F1,F2,F3 and DF)were static,while F0 and PN were dynamic.The CVb/CVw ratio was greater than 1.0 for all acoustic parameters analyzed,with between-individual variation being higher than within-individual variation.Combined the results of PCA and PFA,F1,DF and CD were potentially useful in individual discrimination of X.boettgeri.These findings provide valuable information for future studies on the taxonomy and phylogeny of the Xenophrys. |
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