Premium
Use of Life Tables in Analysing the Dynamics of Copepod Populations
Author(s) -
Gehrs Carl W.,
Robertson Andrew
Publication year - 1975
Publication title -
ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.144
H-Index - 294
eISSN - 1939-9170
pISSN - 0012-9658
DOI - 10.2307/1935500
Subject(s) - survivorship curve , copepod , instar , population , biology , reproduction , ecology , demography , fecundity , population dynamics , zoology , larva , crustacean , sociology
The population parameters have been characterized for the generations that developed during a complete reproduction year of a population of the calanoid copepod Diaptomus calvipes Schacht. A model is presented to calculate the numbers of each of the various instars of a copepod produced during any previous interval of time. Life tables were constructed from laboratory data and for the five generations of the 1971 field population as an aid in studying the population dynamics. Successful reproduction in the field population occurred from mid—March until mid—October. Development time increased for successive instars of the same generation. All generations had similarly shaped survivorship curves and there was a progressively lower rate of survival in successive generations. This lower survival rate was related to decreasing survival during the early naupliar stages. Survivorship of adults was characterized by a rectangular curve. Greatest mortality rates occurred during the egg to fourth naupliar interval (N—IV) and in the sixth naupliar stage (N—VI). Critical controlling factors in this population appear to be those which affect either survivorship in the interval between egg and N—IV or reproductive activity of adults.