Aggressivity in populations of Italian Wall Lizard, Podarcis siculus (Rafinesque, 1810) on Pod Kopište and Pod Mrčara Islands

Radi istraživanja, 1971. godine je 5 parova primorskih gušterica, Podarcis siculus, preneseno s njihovog prirodnog otoka Pod Kopište na otok Pod Mrčara. Nakon 36 godina, znanstvenici su otkrili da je unesena vrsta istrijebila tamošnju autohtonu vrstu gušterice (Podarcis melisellesis) te da se dogodila brza adaptivna evolucija. Utvrdili su razlike u morfologiji, anatomiji i fiziologiji, ali i u ponašanju između jedinki na ta dva otoka. Cilj ovog rada bio je utvrditi razlike u agresivnosti između populacija te između spolova unutar i između tih dviju otočnih populacija. Istraživanje je provedeno na 42 jedinki P. siculus s Pod Mrčare i 50 jedinki s Pod Kopišta. Prije početka istraživanja, jedinke su prošle trodnevno razdoblje habituacije nakon čega je uslijedilo testiranje u otvorenom polju gdje su se istraživale tri glavne kategorije ponašanja vezane za interakciju s drugim gušterom (tolerantnost, agresivnost i povlačenje) i vrijeme provedeno u centralnoj zoni arene kao pokazatelj dominantnosti. Istraživanje je pokazalo da su i mužjaci i ženke s Pod Kopišta agresivniji i od mužjaka i od ženki s Pod Mrčare te da je općenito populacija s Pod Kopišta agresivnija i dominantnija. Nadalje, rezultati su pokazali da su agresivnost i povlačenje povezani pa se agresivnija populacija s Pod Kopišta i više povlači.For the study purposes, in 1971., five pairs of Italian wall lizard, Podarcis siculus, were transfered from their native island Pod Kopište onto Pod Mrčara island. After 36 years scientists discovered that translocated lizard species wiped out the indigenous lizard species (Podarcis melisellensis) and rapid adaptive evolution occured. They found differences in morphology, anatomy, physiology and bihavioural changes between individuals on this two islands. Our aim was to determine differences in aggression between populations and between gender within and between this two island populations. The research was carried out on 42 individuals of P. siculus from Pod Mrčara and 50 individuals from Pod Kopište. Prior to the experimental procedure, individuals passed the three-day habituation period followed by open field testing in which we investigated three main behavioral categories related to interacting with another lizars (tolerance, aggression and retreat) and time spent in the central arena zone as an indicator of dominance. The research have shown that both males and females from Pod Kopište are more aggressive then both males and females from Pod Mrčara, and that in general the population from Pod Kopište is more aggressive and dominant. Furthermore, the results have shown that aggression and retreat are related, so the more aggressive population from Pod Kopište is retreating more