Intra- and interspecific responses to Rafinesque’s big-eared bat (Corynorhinus rafinesquii) social calls

Although there has been a great deal of research on the structure and function of echolocation calls used for foraging and commuting, relatively little research has been conducted on the communication functions of bat vocalizations (Pfalzer and Kusch, 2003). In addition to echolocation calls, bats produce social calls which differ from echolocation calls in structure and function (Fenton, 2003). Social calls are usually longer in duration and lower in frequency than echolocation calls and thus, are more effective at longer distances (Pfalzer and Kusch, 2003). Social calls include mating calls, alarm calls, territorial calls, and food calls (Wilkinson, 1995) and can aid in finding patchily distributed food resources (Wilkinson, 1992; Safi and Kerth, 2007) and roosts (Ruczyński et al., 2007, 2009). In contrast, echolocation calls are used to gain information about the environment (Fenton, 2003). Because echo location calls can be intercepted by other bats, they also can serve a communication function, as in the case of eavesdropping (e.g., Barclay, 1982; Bal combe and Fenton, 1988; Gillam, 2007). Further, differences in echolocation call structure may play an important role in species recognition (Russo et al., 2007). Bats exhibit a wide range of responses to echolocation and social calls made by other bats. Calls may attract bats to a common foraging area (e.g., Wil kin son, 1992) or act as a spacing mechanism (Leonard and Fenton, 1984; Barlow and Jones, 1997). Some bats respond only to the calls of conspecifics whereas others respond to both conspecifics and heterospecifics. Myotis yumanensis and Myotis lucifugus in British Columbia only respond to the echolocation calls of conspecifics (Balcombe and Fenton, 1988), but M. lucifugus in Ontario respond to echo location calls of conspecifics as well as to calls of Eptesicus fuscus (Barclay, 1982). Further more, responses may vary with echolocation call type. Individuals of Tadarida bra si liensis are attracted to Acta Chiropterologica, 12(2): 329–336, 2010 PL ISSN 1508-1109 © Museum and Institute of Zoology PAS doi: 10.3161/150811010X537909