Physiological And Behavioural Ecological Study On Adaptation Of Terrestrial Collembola(3 Species) To Wetland Environment Of Sanjiang Plain, Northeast China

Wetland is one of most important ecosystem types of the biosphere, which is of great environmental value. Biodiversity play crucial role at ecosystem stability. Thus, wetland-ecosystem protection is dependent on biodiversity preserving to an extent. Wetland of Sanjiang Plain, Northeast China is a quite important repository of animal resource, which huge invertebrates resources contained in is quite vital for stability of wetland-Ecosystem. However, following the increased process of land conversion from mash into cropland nowadays, the wetland is so broadly reclaimed that the area of the wetland is decreased rapidly and the biodiversity is seriously destroyed. Considering the constant inundating and suffering long period of low temperature at the wetland environment in Sanjing Plain, we choose two demastic Collembola species Protaphorura bicampata, Lobella sokamensis and a model species Folsomia candida and as sample to study the fearture of their adaptation to the environment to demonstrate the role of land reversion on the terrestrial springtail biodiversity and provide literature support for biodiversity protection in wetland-ecosystem.Integrate the characteristic of wetland environment and the biological feature of terrestrial springtail, the present thesis used biological, behavioral and neurophysiological methods to study the adaptation of the animals to the temperature, water, animals and plans environment. Tempterature adaptation study results showed, as one of the dominant species of Cropland P. bicampata is the typical temperate zone species whose optimum growth and development temperature is 25 ℃. The main strategy to overwinter is diapause through adult but not eggs. Under the temperature buffering effect of soil, vertical migrating or aggregating behavior is necessary for P. bicampata to preparing for diapause before winter was coming. is able to enter the period of growing and deveping earlier with the help of adult diapause than those with eggs. Thus, the temperature of cropland soil recovered earlier than that in wetland of Northeast China, which gave the animals as P. bicampata priority to seize the sesources and nutrition. That might be the main reseason that P. bicampata getting rich at cropland. Passlively resistance to low temperature in Endogeic Collembola was displayed by P. bicampata. The domainence of the P. bicampata at cropland is caused by lefting over of the species at some extent. The study of L. sokamensis adaptiveness applied habitat choice analyss. The water preference was test with slope arena, whose results showed L. sokamensis preferred dryer area and repelled to liquid water. It is illustrated the speices is not water-depencent Collembola in behavior and water is not the reson for their habitate choice. Meanwhile, the wetland moss choice test showed L.sokamensis were attracted by wetland moss, and the attraction displayed the Collembola spcies-specific and moss spesies universal. The moss attarctiveness test in dark condition and segreting of dry moss and water illustrated the moss attraction was induced by by olfactory cues. Furthermore, immobility behavior were observed at L. sokamensis. This behavior is quite efficient for escaping from water when the animal was floating on water surface. It illustrated that L. sokamensi had long term of water adaptation and water is importance for their population diffusion. Hence, the special distribution of L. sokamensis was proved of being decided by wetland moss, olfactory information is important for environmental sensing and water is important for wide distribution of the species. Concerning the important of olfactory cues at habitat choice, the thesis conducted neurophysiological and chemical ecological study concerning the aggregation behavior at model animal, F. candida The results of showed that there were three neurons electrical signal contained in sensilla Organ III, the same as the other researcher reported with anatomical methods. Chemicals responsible for aggregation behavior is mixture of fatty acids who did not active respond of the neuron at Organ III. But the respond of Organ III was detected when applied Phenylacetaldhyde, 2-Pyrrolidinone and Benzaldhyde. Behavioral experiment tested the repellent effect of the mixture of three small molecules with high concentration. The results illustrated that Organ III might be alarm pheromen in F. candida but not responsible for aggregation behiaivor.Integrating all the results of present study: seasonal microtherm is one of most important factors that lead to change of terrestrial Collembola funa structure during Land reversion of Sanjiang Plain, Northeast China. Endogeic sprintails(P.bicampata) adapt farming soil better and were selected by farming land. Wetland plant is essential for some special species(L. sokamensis) existing in wetland-ecosystem. We conclude that cultivation activity and plants resource should be paid attention at biodiversity protection of wetland and that chemical ecological method is quite a beneficial method at biodiversity study.