Validation and Analyses of The Simple method For Determining rm of aphids and Mites

This paper deals with the validation and theoretical analyses of a simple method for calculating the intrinsic rate of increase,rm,of aphids and mites.This method does not require a detailed fecundity table data.The value of rm can be estimated by the simple equation:rm=0.74 ln (Md)/d,where d is the time from birth to first reproduction;Md is the number of female offspring produced per original female in 2 d.This method was developed by Wyatt and White.We reached the following conclusions from our study:When the parameter,Md is less than 1,this equation is not appropriate for estimating rm of populations;When the parameter,Md is larger than 1 and about 70% or more of the reproductive contribution to the rm is achieved in 2d,the equation is appropriate for calculatng the rm of aphids and mites.As Md decreases,the required reproductive contribution to the rm in 2 d corresponding to the constant 0.74 will increase.However,whether 70% or more of reproductive contribution to rm is achieved in 2 d still is a problem for whole taxa of aphids and mites.Therefore,further study on reproductive distribution will be required for practical application of this method.