POLYGYNY IN THE PIED FLYCATCHER (FICEDULA-HYPOLEUCA) - COMPARISON OF DECEPTION AND NON-DECEPTION MODELS

Since the evolutionary significance of polygynous mating systems was f irst recognized, many models have been proposed to explain why females mate with already-mated males. In the pied flycatcher (Ficedula hypol euca), a particulary well studied polygynous passerine species, two mo dels of polygyny are most prominent nowadays: one in which already-mat ed males deceive the females about their mating status, and one in whi ch the status of already-mated males is known to the females that deci de to male with them anyway, ''making the best of a bad job''. In our study we compared the models by computer simulation and then compared the results with available field data. The results showed that the pro portion of secondary females increased when the density of males incre ased, as well when the operational sex ratio increased in favour of fe males. However, these results were indistinguishable between the model s when number of simulation repetitions was low. This may suggest that a secondary female frequencies collected in the field may not be a go od test of which model (deception or non-deception) better explains po lygyny in the pied flycatcher unless the data are collected for a suff icient number of breeding seasons (at least 20).