Invasive Species Compendium

Detailed coverage of invasive species threatening livelihoods and the environment worldwide

Abstract

Demographic characteristics of two freshwater cyclopoid copepods in Mexico, fed a plankton diet: the native Mesocyclops longisetus Thiébaud and the invasive Mesocyclops pehpeinsis Hu.

Abstract

The introduction of exotic species often results in a loss of biodiversity. Mexico has 4 invasive species of freshwater cyclopoid copepods: Thermocyclops crassus, Mesocyclops aspericornis, M. thermocyclopoides, and M. pehpeiensis. The Asian cyclopoid M. pehpeiensis is now established in several lakes and rivers in Mexico, but how it might compete with native species and potentially change the structure of plankton communities is unknown. Some insights might be obtained from a study of its demography compared to that of a native species. We compared the life cycle parameters of the native Mesocyclops longisetus and the exotic invasive species M. pehpeiensis in separate cultures. Four treatments were set up with 2 densities of Plationus patulus (Rotifera) individuals (1 and 4 m L-1) and 2 concentrations of Scendesmus acutus (Chlorophyte) cells (0.5 × 106 and 1.5 × 106 mL-1). Both species survived and reproduced in the treatment of 4 mL-1 of P. patulus individuals + 0.5 × 106 mL-1 of S. acutus cells. Mesocyclops pehpeiensis had common characteristics in successful invasive species: short generation time, high reproductive capacity, and a wide dietary range. At low rotifer densities, M. pehpeiensis had a higher population growth rate (0.12 d-1) compared to M. longisetus (0.08-0.10 d-1). M. pehpeiensis is likely to outcompete M. longisetus, especially under food-limited conditions, and most likely expand its range in Mexico.