Competitive Exclusion Due to Mate Searching Behaviour, Male-Female Emergence Lags and Fluctuation in Number of Progeny in Model Invertebrate Populations

Abstract

A deductive computer population was developed to study the effects of simple behavioral attributes of adults on numbers of their progeny. The main parameters are the SD of time of appearance of adults, population size of the adults during the generation, adult survival rates and mate-locating ability/searching area of the population. Mating occurs at random; delayed mating reduces reproduction. Interspecific differences in mae-locating behavior are a potent competitive exclusion mechanism. Two species cannot occupy the same niche if their mate-locating efficiency differs. Selection creates a lag in emergence such that males become adult prior to females. Progeny per female is lowered by increasing the SD of emergence time, by decreasing population density, and by decreasing mate-locating efficiency. Survival rate of females is much more important than that of males in influencing progeny production, unless males are rare. Temporal fluctuations of progency due to fluctuations of population size are reduced by behavioral mechanisms which produce a positive correlation between searching area and population size, produce a negative correlation between mate-locating efficiency and population size, and by the development of a prereproductive period in which mating can occur.