Hybrid Populations of Daphnia from some Lakes on Vancouver Island, British Columbia

Abstract

Daphnia from five lakes on Vancouver Island in British Columbia are reasonably classifiable as three different species. D. pulex Leydig, D. rosea G. O. Sars and D. thordta Forbes. The individuals of all the populations have, however, not only some typical appearance of each respective species, but also have some characteristics of two species in various degrees, probably due to introgressive hybridization. From this point of view their characteristics are discussed, suggesting possible hybridization between D. pulex and D. middendorffiana, between D. rosea and D. middendorffiana, and between D. thorata and D. rosea. The writer can make no further comments on the real nature of these interspecific forms than only to give their characteristics.