Estimating population birth rates of zooplankton when rates of egg deposition and hatching are periodic

I present a general method of computing finite birth and death rates of natural zooplankton populations from changes in the age distribution of eggs and changes in population size. The method is applicable to cases in which eggs hatch periodically owing to variable rates of oviposition. When morphological criteria are used to determine the age distribution of eggs at the beginning and end of a sampling interval, egg mortality can be incorporated in estimates of population birth rate. I raised laboratory populations of Asplanchna priodonta , a common planktonic rotifer, in semicontinuous culture to evaluate my method of computing finite birth rate. The Asplanchna population became synchronized to a daily addition of food but grew by the same amount each day once steady state was achieved. The steady-state rate of growth, which can be computed from the volume-specific dilution rate of the culture, was consistent with the finite birth rate predicted from the population's egg ratio and egg age distribution.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/47764/1/442_2004_Article_BF00410359.pd

Competition Relatedness And Efficiency

Seger has argued that, if a law of diminishing returns of personal fitness with increasing consumption of a limiting resource applies, a greater increment to inclusive fitness3 may accrue to an individual by sharing the resource with its relatives than by excluding them. That is, from the point of view of an individual's inclusive fitness, there will exist an optimal relation between resource abundance, conversion efficiency (in terms of increment in personal fitness per resource unit consumed) and competitor abundance and relatedness to the subject. Here, this is rendered more concrete by deriving expressions for the optimum consumption rate for any one of a number of related individuals competing for a finite resource