Basic characteristics of the investigated reservoirs, their occupancy by taxa of the D. longispina complex and the number of analysed individuals (for allozymes, data for each year are shown separately; variation in numbers is caused by the occasional absence of Daphnia in the hypolimnion and/or scoring problems). (Species (D. galeata, D. cucullata and D. longispina) are abbreviated by the first letters of their species names; taxa composing at least 5% in any sample from the particular reservoir are listed in uppercase, accessorial taxa recorded in lower relative abundances are in lowercase. The asterisk indicates the locality where all ‘hybrid’ individuals were probably backcrosses or later-generation hybrids; cases where one of the parental species of a hybrid was not detected in a particular reservoir are marked by the hash symbol. More details about reservoirs (geographical position, altitude and age) can be found in Seda et al. 2007b.)