Abstract # 2300 Poster # 149:

Scheduled for Friday, June 22, 2007 05:00 PM-07:00 PM: Session 14 (South Main Hall) Poster Presentation

Functional Significance of Sexually Dimorphic Acoustic Structures in Wied’s Black Tufted-ear Marmoset (Callithrix kuhlii)

A. S. Smith, K. R. Lane, A. K. Birnie and J. A. French
University of Nebraska at Omaha, Callitrichid Primate Research Center, Department of Psychology, Omaha, NE 68182, USA
     In callitrichid primates there is little sexual dimorphism, so the ability to recognize sex from long distances depends on phee calls. In the absences of visual stimuli, acoustic structures of callitrichid phee calls may act as primers for proper behavioral responses in within-and between-group social interactions. In this study, acoustic structures of various frequency and temporal values were analyzed to determine sexual dimorphism in phee calls. Phee calls were sexually dimorphic, but only frequency values (i.e. peak, end, lowest) were significant [F(1,17)=6.46, p<0.021]. Playback techniques and acoustic modification were then used to explore the relationship between social behavior and acoustic structures. In eight male-female marmoset pairs, results indicated when controlling for sex of responder frequency of head scans significantly increased from the average pre-condition minute to the first post-condition minute [F(1,3)=7.53, p=0.034]. When controlling for sex of caller, proximity between the responding pair significantly changed between the pre-and post-condition [F(1,3)=5.04, p=0.045].The proximity of the pair significantly increased after a male call [F(1,3)=5.58, p=0.050] and decreased after a female call [F(1,3)=6.09, p=0.043]. By studying behavioral responses of males and females to same and opposite sex callers we established functional significance of acoustic structures in phee calls for identifying sex of caller. Results promote the idea that recognition of sex in acoustic cues is a multivariate process, depending on a congruency of acoustic features that give rise to sex identity.