The Effect Of Seed Morphological Traits On Dropping Rates Of Seed In Ant-mediated Dispersal Of The Four Corydalis Plants

The evolution of seed dispersal mutualisms has been debated for many years.Seed dispersal is a fundamental life history trait in plants.When ants find the seed which bears elaisome,then select the favorite ones,transport to nest or not,abandon the diaspore after eating up the elaiosomes.Adaptive seed traits,such as seed weight,seed size,and ant community composition and behavior affect the dispersal effectiveness include dispersal distance and dispersal rate.In this paper,we study the dropping rates of four plants in Corydalis DC.They are in diplochorous system.C.hemsleyana and C.acuminata are endemic plants,which are ballistic dispersal,wheras C.sheareri S.Moore f.sheareri and C.temulifolia Franch.ssp.temulifolia are widespread plants,which are barochory.We compare the seed size,seed weight and ant size to estimate the effect of seed traits on dropping rates of these plants.The purpose of this study was to evaluate the mutualism of myrmecochorous and ants.The main findings are as follows:1.The dropping rates of seed vary among these plants.In the serial of C.sheareri S.Moore f.sheareri,C.acuminate,C.temulifolia Franch.ssp.temulifolia,C.hemsleyana,the dropping rates increase.In the analyze of correlation,it shows that the dropping rates of seed correlate significant positively with diaspore weight(including elaiosome),seed weight(excluding elaiosome),elaiosome weight(Spearman Correlation,r=0.966,P=0.034;Spearman Correlation,r=0.953,P=0.047;Spearman Correlation,r=0.982,P=0.018).The dropping rates of seed are no correlation with seed size and seed weight/elaiosome weight ratio.The variations in ant size of Pheidole sp.,Paratrechina yerburyi,Lasius alienus are significant.2.The mean ballistic distance of seed of C.hemsleyana is 49.94 cm(n=355).The maximum ballistic distance of seed of C.hemsleyana is 214.09 cm.The mean ballistic distance of seed of C.acuminata is 60.43 cm(n=369).The maximum ballistic distance of seed of C.acuminata is 248.22 cm.The ballistic distance of seed of C.acuminata is furthcr than C.hemsleyana.In the serial of C.sheareri S.Moore f.sheareri,C.acuminate,C.temulifolia Franch.ssp.temulifolia,C.hemsleyana,the removal rates decrease.The C.sheareri S.Moore f.sheareri is more dependent on myrmecochorous dispersal,whereas C.acuminate is more dependent on ballistic dispersal.