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The objectives of this work were to clarify the spatial distribution pattern of the overwintering eggs of M.hieroglyphica(Motschulsky).An investigation with stratified random sampling was conducted on the egg number in corn field of Jinzhong,Shanxi province in October 2011.The spatial distribution pattern of the overwintering eggs of M.hieroglyphica in soil was studied by determination of frequency distribution,aggregated indices,the improved Iwao′s regression equation and Taylor′s power law.The reasons for the aggregation of the overwintering eggs of M.hieroglyphica was analyzed according to estimation by aggregation mean(λ).Results indicated that the overwintering eggs of M.hieroglyphica belong to negative binomial distribution and the aggregated indices of overwintering eggs met C1,CA0,I0,k0,m*/m1,so M.Hieroglyphica eggs in soil presented pattern of aggregation distribution in low population density,and its fundamental component was the individual that was mutually exclusive.The rate of relative aggregation change of fundamental component was 3.52m-15.61,which changed with the population density of overwintering egg of M.hieroglyphica.The greater the population density of overwintering eggs,the greater the change rate of relative aggregation degree.The degree of aggregation increased with the population density of overwintering eggs.Aggregation mean λ value indicated that the aggregation might be due to the combined actions of the oviposition habits of adults and other environmental factors,including the growth of vegetation,soil features,temperature and humidity,etc.Female of M.hieroglyphica usually deposited the overwintering eggs below the soil surface.It was observed that the 94.2% of the eggs were laid in the top 10 cm between 0 and 15 cm of the soil surface.In addition,the number of M.hieroglyphica eggs between 2 and 5 cm below the soil surface was significantly more than others with an average value of 25.56 in every sample,which is 64.7% of the total. |
