Meeting Abstract

S8-1.4  Jan. 6  Colour polymorphism without ecological niche divergence in the lacertid lizard Podarcis melisellensis HUYGHE, Katleen*; VANHOOYDONCK, Bieke; HERREL, Anthony; VAN DAMME, Raoul; Univ. of Antwerp, Belgium; Univ. of Antwerp, Belgium; Univ. of Antwerp, Belgium; Univ. of Antwerp, Belgium

Different hypotheses have been proposed to explain the origin of phenotypic polymorphisms. Non-adaptive mechanisms (gene flow, stochastic effects) are difficult to investigate and can be the original cause of such polymorphisms in a population, but they cannot explain their maintenance. Adaptive mechanisms on the other hand can explain the origin and the continued existence of polymorphisms, and can mainly be classified into three types depending on the selective pressures operating on the system: 1) trade-off in natural vs. sexual selection 2) frequency-dependent selection and 3) natural selection s.s.. Here we investigate the role of natural selection s.s. in the co-existence of three colour morphs in the lacertid lizard Podarcis melisellensis. In this species, males and females occur in 3 different colour morphs that differ in their abundance. We quantified a number of ecological and behavioral parameters that are expected to differ between morphs. First, the spatial distribution of individuals was mapped to look at the level of aggregation between morphs. Preliminary results suggest no differences here. Niche divergence may possibly also manifest itself in differential microhabitat use or thermal ecological parameters, but no obvious differences were found between the colour morphs. These results seem to suggest that niche divergence through natural selection is not the cause of the striking phenotypic polymorphism in these lizards.