Parabolic Higgs bundles on a Riemann surface are of interest for many reasons, one of them being their importance in the study of representations of the fundamental group of the punctured surface in the complex general linear group. In this paper the authors calculate the Betti numbers of the moduli space of rank 3 parabolic Higgs bundles with fixed and non-fixed determinant, using Morse theory. A key point is that certain critical submanifolds of the Morse function can be identified with moduli spaces of parabolic triples. These moduli spaces come in families depending on a real parameter and the authors carry out a careful analysis of them by studying their variation with this parameter. Thus the authors obtain in particular information about the topology of the moduli spaces of parabolic triples for the value of the parameter relevant to the study of parabolic Higgs bundles. The remaining critical submanifolds are also described: one of them is the moduli space of parabolic bundles, while the rem
Introduction Parabolic Higgs bundles Morse theory on the moduli space Parabolic triples Critical values and flips Parabolic triples with $r 1=2$ and $r 2=1$ Critical submanifolds of type (1, 1, 1) Critical submanifolds of type (1,2) Critical submanifolds of type (2, 1) Betti numbers of the moduli space of rank three parabolic bundles Betti numbers of the moduli space of rank three parabolic Higgs bundles The fixed determinant case Bibliography.