Life history responses of Amphiascus tenuiremis (Copepoda, Harpacticoida) to mimicked predation

Abstract

Control populations initially contained 100 copepodites, 100 adult males and 100 adult females. In experimental treatments, one of these components was reduced by 90 or 50% to mimic 30 or 17% once-in time predation impact. Abundance increased in all populations, and at both levels removal of females (female treatment) resulted in significant decreases in total abundance after 21 d (one generation). Copepodite and male removal had no significant effect on total population size. In 50% removals, final number of nauplii and copepodites was lower in female treatments only. Number of males was significantly lower in male treatments at both levels of removal, as was number of females in female treatments. Female specific predation had the greatest effect on these copepod populations. Total population size decreased because number of nauplii (which comprised 75-80% of each population) was significantly decreased. High reproductive potential, as indicated in up to 28-fold increases in population size over one generation, intimated that the observed changes in population size and composition would not be enduring. Predation would play a small role in determining population structure of A. tenuiremis. -from Authors