Author's personal copy The relationships between cuticular hydrocarbon composition, faunal assemblages, inter-island distance, and population genetic variation in Tuscan Archipelago wasps Leonardo Dapporto a, b , Aviva E. Liebert c, * , Philip T. Starks c , Stefano Turillazzi a, b a Dipartimento di Biologia Animale e Genetica, Universita ` di Firenze, via Romana no 17, 50125 Florence, Italy b Centro Interdipartimentale di Spettrometria di Massa, Universita ` di Firenze, Viale G. Pieraccini no 6, 50100 Florence, Italy c Department of Biology, Tufts University,163 Packard Avenue, Medford, MA 02155, USA article info Article history: Received 7 October 2008 Accepted 30 May 2009 Keywords: Island biogeography Pompilidae Polistes dominulus Tuscan Archipelago Cuticular hydrocarbons Genetic differentiation abstract Until recently, studies examining the geographical distribution of insects in the Tuscan Archipelago have focused on paleogeography as the primary influence on species distri- butions. However, for flying insects such as Hymenoptera that may be able to disperse over water, current geographical location is likely to be more important in determining present distributions within the Archipelago. Here we compare mainland and island wasp pop- ulations using genetic variation and cuticular hydrocarbon composition of the vespid wasp Polistes dominulus, and species composition of wasps in the family Pompilidae. Both chemical and genetic data result in similar clustering of P. dominulus populations that reflect present geographical location. Moreover, we found current geographical distance to be significantly correlated with P. dominulus population genetic differentiation and Pom- pilidae faunal composition. These data suggest that dispersal over present sea distances is more important in determining population differentiation and species distribution in the Tuscan Archipelago than paleogeography. Ó 2009 Elsevier Ltd. All rights reserved. 1. Introduction In the last two centuries much effort has been spent investigating how living and fossil animals could have reached their geographical distribution. Generally two hypotheses have been considered as opponents in determining species distribution: the vicariance and the dispersal hypotheses. The former predicts that a species becomes separated into two populations by some newly emerged barrier and the populations then diverge in different areas, while the latter predicts that a species evolves and spreads from a center of origin until it reaches some physical or ecological barrier (Williamson, 1981; Whittaker, 1998). Due to the possibility of supporting the continental drift hypothesis and predicting or explaining species distribution on the basis of continental movement, the vicariance model has received the majority of attention. Nevertheless evidence from recent studies suggests that the distribution of highly mobile organisms on continental islands (e.g., those in the Mediterranean Sea) can be explained best by recent geography rather than paleogeography (Dennis et al., 2000; Hausdorf and Hennig, 2005; Dapporto et al., 2007a; Dapporto and Cini, 2007; Dapporto and Dennis, 2008). The assessment of similarity * Corresponding author. Present address: Department of Biology, Framingham State College, 100 State Street, Framingham, MA 01701-9101, USA. Tel.: þ1 508 626 4790; fax: þ1 508 626 4794. E-mail addresses: leondap@gmail.com (L. Dapporto), aliebert@framingham.edu (A.E. Liebert), philip.starks@tufts.edu (P.T. Starks), stefano.turillazzi@ unifi.it (S. Turillazzi). Contents lists available at ScienceDirect Biochemical Systematics and Ecology journal homepage: www.elsevier.com/locate/biochemsyseco 0305-1978/$ – see front matter Ó 2009 Elsevier Ltd. All rights reserved. doi:10.1016/j.bse.2009.05.018 Biochemical Systematics and Ecology 37 (2009) 341–348