ARTICLE Mating behavior of Aegla platensis (Crustacea, Anomura, Aeglidae) under laboratory conditions M. Almera ˜o Æ G. Bond-Buckup Æ M. de S. Mendonc ¸a Jr Received: 26 October 2007 / Accepted: 13 March 2009 Ó Japan Ethological Society and Springer 2009 Abstract The mating behavior of several decapod crus- taceans has been extensively studied; however, this aspect of anomuran biology is still poorly known in some groups. Aeglids are the only anomurans inhabiting freshwaters, and the mating behavior of the species in this family is unknown. We provide the first account of the mating behavior of an aeglid, Aegla platensis, under laboratory conditions. The precopulatory phase was characterized by male agonistic display, male approach, and courtship. Males exhibited the agonistic display toward immature and mature females, but only physiologically mature females allowed males to approach. Male approach led to display of courtship behaviors (body vibration, thrust, body lifting, and abdomen flapping). During the copulatory phase, males and females touched each other with the antennae (anten- nae touch), and males positioned themselves beneath the females (supine position). Although sperm transfer was not directly observed, a ‘‘white mass’’ was detected among oocytes in the female abdominal chamber shortly after some copulations. Finally, in the postcopulatory phase, males guard females during the process of egg attachment. Despite their morphological similarities with other anomurans, the mating behavior of aeglids seems to be unique, and the freshwater environment appears to have an important role in driving these differences. Keywords Crustacea Á Anomura Á Aeglids Á Aegla platensis Á Mating behavior Introduction The mating behavior of many decapod crustaceans has been studied (e.g., Hartnoll 1969; Salmon 1983; Christy 1987; Diesel 1991; Bauer 1996, 2000; Gherardi 2002), but this aspect is poorly known in some groups. Anomurans are the most peculiar group of decapod crustaceans due to their morphological and behavioral diversity, which is also evi- denced by the diversity of their mating behavior strategies (Salmon 1983). In this group, such strategies have been studied mainly in hermit crabs (Hazlett 1981; Goshima et al. 1995; Hazlett 1996a, b; Wada et al. 1997; Minouchi and Goshima 1998; Wada et al. 1999; Hess and Bauer 2002; Tudge and Lemaitre 2004; Turra 2005). In other groups including mole crabs, porcellanids, galatheids, and chiro- stylids crabs, sexual behavior is almost unknown (Efford 1967; Molenock 1975; Wenner 1982; Subramoniam 1977; Diaz 1980; Veloso 1999). Aeglidae is the only freshwater anomuran family and occurs exclusively in the Neotropics. All species inhabit freshwater environments, such as lakes, streams, salt mar- shes, and caves, ranging from depths of 320 m in Chilean lakes to *3500 m above sea level in the northeastern Argentinean cordilleras (Perez-Lousada et al. 2004). Although several aspects of the natural history of aeglids are known, their mating behavior has not yet been investigated. M. Almera ˜o Á G. Bond-Buckup Departamento de Zoologia, Universidade Federal do Rio Grande do Sul, Avenida Bento Gonc ¸alves 9500 pre ´dio 43435, Porto Alegre, Rio Grande do Sul, Brazil M. de S. Mendonc ¸a Jr Departamento de Ecologia, Universidade Federal do Rio Grande do Sul, Avenida Bento Gonc ¸alves 9500 pre ´dio 43422, Porto Alegre, Rio Grande do Sul, Brazil M. Almera ˜o (&) Departamento de Gene ´tica, Universidade Federal do Rio Grande do Sul, Av. Bento Gonc ¸alves n. 9500 Pre ´dio 43323, Porto Alegre, Brazil e-mail: malmerao@hotmail.com 123 J Ethol DOI 10.1007/s10164-009-0159-7