Composition and seasonal variations of macro arthropod fauna associated with cattle dung pats in Songnen Grassland,China
松嫩草地牛粪中大型节肢动物种类组成及种群动态变化

The species and seasonal variations of macro Arthropod fauna associated with cattle dung pats were studied and analyzed based on the results obtained from field investigation and experiments in Songnen Grassland,China.The result showed that the macro Arthropod fauna associated with cattle dung consisted of 43 species from 19 families,including 32 Coleoptera,4 Hymenoptera,2 Diptera,2 Deramptera,1 Orthoptera,1 Araneae and 1 Acariformes.The macro arthropod fauna included 19 coprophagy species,4 saprophagy species,6 phytophagous species,11 predatism species,5 omnivorey species,1 corpse-eating species and 1 parastitism species according to their feeding habits.The adults of Scarabaeoidea whose feeding habits depended on the liquid in the fresh cattle dung were called dung beetles.There were four contrasting patterns of dung use by dung beetles: 6 species paracoprids,5 species endocoprids,2 species telecoprids and 1 species kleptoparasistes.Statistical analysis showed that except for Onthophagus bivertex,the number of arthropod fauna species of Aphodius restus(Y_1),fly larva(Y_2),Ocypus parvulus(Y_3),Tetramorium caespitum(Y_4) and Total number of arthropod fauna species(Y_5) were all significantly related to the weight of the fresh cattle dung pats(X).The relationships could be fitted into the linearity function,Y_1=6.49X 0.04(R=0.84,p<0.01),Y_2=8.84X-3.20(R=0.87,p<0.01),Y_3=5.20 0.09(R=0.86,p<0.01),Y_4=45.73-12.65(R=0.93 p<0.01),Y_5=74.87X-3.58 (R=0.91,p<0.01) respectively.The species and amount of coprophagy species decreased rapidly,and nearly disappeared after 7 days of fresh cattle dung pats disposition.There was a significantly negative correlation between the amount of coprophagy species(Y) and the days(X_1) after the dung pats disposition in 7 days,and a significantly positive correlation between the amount of coprophagy(Y) and the water content of the cattle dung pats(X_2).The relationships could be fitted into the linearity function,Y=-33.52X_1 146.01(R=-0.95,p<0.01),Y=5.16X_2-237.31(X=0.92,p<0.01).The variations of the different feeding habit species were relative to the dung water content,and it indicated that the arthropod species occupied different niches according to their different feeding habits.The coprophagy species dominated the fresh cattle dung pats,and the predateism and omnivorey species dominated the dry cattle dung pats.The dominant species associated with cattle dung were Aphodius rectus(69.25%) and the fly larvae of Musca amita and Haematobia exigua(25.12%) from April to September. Dung beetles dominated the fresh dung pats in April,May,June and September,the fly larvae of Musca amita and Haematobia exigua dominated the dung pats in July and August.The seasonal variations of dung beetles and the fly larvae of Musca amita and Haematobia exigua were affected by temperature,precipitation and the dung water content.