Male breeding success is predicted by call frequency in a territorial species, the agile frog (Rana dalmatina) David Lesbarre ` res, Juha Merila ¨ , and Thierry Lode ´ Abstract: Calling behaviour and the characteristics of the male call are important for both female mate choice and male mating success in anurans. As with most other ranid frogs, males of the agile frog (Rana dalmatina Fitzinger in Bonaparte, 1839) emit advertisement calls during the mating period. However, since males occupy and defend territories, it is not clear whether the calls serve to defend a territory and (or) to attract a mate. We investigated the relationship between male call characteristics and male breeding success in a field study by relating individual males’ call parameters (viz. call dura- tion, number pulses, pulse rate, and fundamental frequency) with their breeding success as indicated by the number and size of egg clutches in the territories of males. We found that the number and size (in number of eggs) of clutches in the territories of males increased with decreasing fundamental frequency of calls. We found no correlation between territory characteristics and breeding success, suggesting that the observed correlation between male call characteristics and mating success is not likely to be explained by differences in territory quality, but by female potential preference for males calling with low fundamental frequency. Re ´sume ´: Chez les Anoures, le chant et ses caracte ´ristiques chez le ma ˆle sont importants a ` la fois pour le choix des fe- melles et le succe `s reproducteur des ma ˆles. Comme la plupart des autres ranide ´s, le ma ˆle de la grenouille agile (Rana dal- matina Fitzinger in Bonaparte, 1839) e ´met un chant d’appel durant la saison de reproduction. Cependant, comme les ma ˆles occupent et de ´fendent un territoire, il reste a ` de ´terminer si le chant sert a ` la de ´fense du territoire et (ou) a ` l’at- traction d’un partenaire. Nous avons e ´tudie ´ la relation entre les caracte ´ristiques du chant du ma ˆle et son succe `s reproduc- teur en e ´tablissant les parame `tres de chant individuels (dure ´e, nombre de pulsations, taux de pulsations et fre ´quence fondamentale) ainsi que leur succe `s d’accouplement repre ´sente ´ par le nombre et la taille des pontes au sein du territoire de chaque ma ˆle. Nous avons observe ´ que le nombre et la taille (en nombre d’œufs) des pontes augmentaient avec la diminu- tion de la fre ´quence fondamentale. En revanche, nous n’avons pas trouve ´ de corre ´lation entre les caracte ´ristiques du terri- toire et le succe `s de l’accouplement, sugge ´rant que la relation entre les caracte ´ristiques du chant du ma ˆle et son succe `s d’accouplement ne repose probablement pas sur la qualite ´ diffe ´rentielle du territoire, mais sur une possible pre ´fe ´rence des femelles pour les ma ˆles chantant avec une fre ´quence fondamentale basse. Introduction Male sexual ornaments such as conspicuous colors, struc- tures, or complex acoustic calls are thought to have evolved through sexual selection (Andersson 1994). Sexual selection can either occur through competition between the members of a single sex (generally males for mates) or through choice exerted by members of other sex (generally females; Ander- sson 1994). In numerous taxa, an advertisement call is a trait involved in reproduction. In anurans, part of the energetic cost involved with the production of the call is in its dura- tion (Schneider et al. 1988; Bee and Perrill 1996; Welch et al. 1998; Gerhardt et al. 2000). The calling activity requires a more or less prolonged vocal effort by the male and may represent an important part of the male reproductive invest- ment (Wells and Taigen 1986; Ryan 1988). Meanwhile, the female perception of the variations in the advertisement call is thought to affect female choice (Ryan and Keddy-Hector 1992; Marler and Ryan 1997). The male advertisement call may be dependent on social conditions (Wells 1977a; Wells 1988; Murphy 2003a). In some species, the chorus created by several males calling si- multaneously results in a communal signal that reaches far- ther away than a single caller would (Cocroft and Ryan 1995; but see Murphy 2003b). Males can also produce calls in isolation from other males to avoid having their signals overlapped by other males. In some species, this type of call is associated with a territorial behaviour with males de- fending areas for courtship, mating, nesting, or rearing the offspring, often leading to direct or indirect exclusion of other males (Wells 1977a; Bee and Gerhardt 2001a, 2001b; Lesbarre `res and Lode ´ 2002). In fact, both experimental and Received 3 June 2008. Accepted 2 October 2008. Published on the NRC Research Press Web site at cjz.nrc.ca on 30 October 2008. D. Lesbarre `res. 1 Department of Biology, Laurentian University, Sudbury, ON P3E 2C6, Canada. J. Merila ¨. Ecological Genetics Research Unit, Department of Biological and Environmental Sciences, P.O. Box 65, University of Helsinki, FI-00014 Helsinki, Finland. T. Lode ´. Unite ´ Mixte de Recherche – Centre National de la Recherche Scientifique 6552, Ethologie–Evolution–Ecologie, Universite ´ de Rennes 1, campus de Beaulieu, 35042 Rennes, France. 1 Corresponding author (e-mail: dlesbarreres@laurentian.ca). 1273 Can. J. Zool. 86: 1273–1279 (2008) doi:10.1139/Z08-121 # 2008 NRC Canada