POPULATION GENETIC-STRUCTURE AMONG POPULATIONS OF 3 PREDACEOUS NABID SPECIES - NABIS-ALTERNATUS PARSHLEY, NABIS-ROSEIPENNIS REUTER AND NABIS-AMERICOFEROUS CARAYON (HEMIPTERA, NABIDAE)

An electrophoretic survey of 28 presumptive loci distributed among 15 enzyme systems was conducted to determine the genetic structure among local populations of three predaceous nabid species: Nabis alternatus, N. roseipennis and N. americoferous in human-disturbed habitat. For a ll three species, F(IS) values indicated a deficiency of heterozygotes at most loci in most populations. The amount of genetic differentiati on based on the standardized variance, F(ST) when combined across all populations was 0.100 for N. alternatus, 0.189 for N. roseipennis, and 0.335 for N. americoferous. When local populations were grouped accor ding to a set of defined geographical limits, based on the naturally o ccurring spatial arrangement of the sampled localities, some unexpecte d patterns of genetic variation were revealed. The degree of genetic d ifferentiation detected among local populations of nabids is discussed in light of the frequent disruptions and ecological changes in their ephemeral habitats.