Abstract: There is no doubt that Harmonia axyridis has been successful in suppressing manynative species in North America and subsequently in Europe. It is not quite clear, however, whatare the ecological mechanisms that enabled it to be so successful – is it higher fecundity, moregenerations per year, or competitive superiority, which enable it to suppress native species? HereI critically examine, whether its’ competitive superiority, lending it an advantage in intraguildinteractions, can be an important factor. Empirical data show that the incidence of intraguildpredation (IGP) between ladybird species seems to be very low under natural conditions. Asimple population dynamics model, however, shows that despite this, IGP might play asubstantial role in the success of H. axyridis under some circumstances.