Two Life Strategies in Copepod Cryptic Species: Coexistence and Displacement

Among invasive species there is a special group so named cryptic species for which morphological identification is very difficult. This review is devoted to analysis of the dispersal routes of two copepod cryptic species complexes into aquatic ecosystems. Eurytemora carolleeae introduction was revealed in 2007 with bar-code. The species was described as a new taxon; its distribution was also studied using morphology. Biological invasions of two other Copepod species Acanthocyclops americanus and Eurytemora caspica were mainly studied using morphological methods since the species have already been described. At the same time, to confirm their distinctions from local forms molecular genetic tools were also used. Two scenarios resulting from cryptic species’ invasions and their competitions with native species were the partly ( E. carrolleeae ) or full displacement ( A. americanus ). When assessing the possible negative impact of invasive species on competitors, the most attention should be paid to predator species. Identification of cryptic species significantly complicates the situation with the assessment of bioinvasion and needs the use of molecular methods.