Journal of Insect Behavior, Vol. 18, No. 5, September 2005 ( C  2005) DOI: 10.1007/s10905-005-7019-2 Short Communication Behavioral Bioassays Testing the Methyl 6-Methylsalicylate as a Component of the Female Sex Pheromone in the Slave-Making Ant Polyergus rufescens (Hymenoptera, Formicidae) Cristina Castracani, 1 Roberto Visicchio, 1 Donat ´ o A. Grasso, 1 Alessandra Mori, 1 Francesco Le Moli, 1,3 Alessandra Di Tullio, 2 Samantha Reale, 2 and Francesco De Angelis 2 Accepted February 1, 2005; revised March 22, 2005 KEY WORDS: female-calling syndrome; sex pheromone; methyl 6-methylsalicylate; bioassays; Polyergus rufescens. INTRODUCTION The mating behavior of the slave-making ant Polyergus rufescens is an ex- ample of “Female-calling Syndrome” as defined by H ¨ olldobler and Bartz (1985). In this species, in fact, nuptial flights are inconspicuous and not well synchronized between sexes. Moreover, females typically call for males, do not disperse widely, and remain near their natal nest or return to a dulotic colony after mating. Lastly, the virgin queen usually mates only with the first male that is able to locate her and after mating she cuts off her wings and hides in the vegetation surrounding the nest (Mori et al., 2001). Two main aspects of P. rufescens ecology could explain the mating strategy adopted by this species: the relative low density of both sexes and its parasitic nature. As suggested by Bourke and Franks (1995), female calling could be advan- tageous for species that do not produce a large amount of sexuals: through this mating strategy, females probably maximize their chances of finding a mate. Moreover, female calling is suitable for scattered colonies, like those 1 Dipartimento di Biologia Evolutiva e Funzionale, Universit ` a degli Studi, Parma, Italy. 2 Dipartimento di Chimica, Ingegneria Chimica e Materiali, Universit ` a dell’Aquila, Coppito, L’Aquila, Italy. 3 To whom correspondence should be addressed. E-mail: lemoli@biol.unipr.it 685 0892-7553/05/0900-0685/0 C  2005 Springer Science+Business Media, Inc.