Kayla Hartwell 1, Hugh Notman 1,2, & Mary Pavelka 1 1 University of Calgary and 2 Athabasca University, Alberta, Canada

 Described in a number of studies (Campbell 2003; Link et al. 2009; Slater et al. 2009)  Low intensity intra-group aggression directed from males to females  “Stereotyped displays and chases” (Link et al. 2009) Photo: Kayley Evans

 Sexual Segregation and Aggregation Statistic (SSAS) (Bonenfant et al. 2007)  Association = presence in the same subgroup using 30min subgroup scan data  Distinguishes active segregation and aggregation from random association  Calculates index value ranging from 0 (significant aggregation) to 1 (significant segregation)

1 Jan Mar May Jul Sep Nov SSAS Month (Segregation) (Aggregation)

1.Compare rates of aggression by  Males to females  Males to males  Females to males  Females to females 2.Compare the contexts in which these aggressive interactions occurred

 group members over course of study  All individuals habituated and individually recognizable Year MaleFemales AdultSubadultAdultSubadult

 Collect scan & focal data  All observations of fission- fusion events & aggression  For aggression: ID of director(s) & receiver(s) & context  ~2000 contact hours over 601 days  193 aggressive interactions

 Food: receiver was feeding when aggression occurred  Fusion: subgroup fusion occurred within 5min of aggression (food took precedence over fusion)  Sexual: copulation, place sniff, genital inspect occurred immediately following aggression  Other: any other context

Results 80% M-F (N=154) 15% F-F (N=30) 3% F-M (N=5) 2% M-M (N=4)

 Context of aggression differed between M-F & F-F ( X 2 = 12 df=3 P =.007)  M-F occurred most often during subgroup fusions (38%) or feeding (31%)  F-F occurred most often during feeding (41%) or other (45%)

Sociogram of asymmetric matrix of dyadic aggression rates (arrow points from director to receiver) Males Females Aggression rate/hour

 Patterns of female- directed aggression at Runaway Creek are consistent with that found at other Ateles sites  Results support Link et al. 2009: M-F aggression is a form of social control (indirect sexual coercion)  May encourage sexual segregation as females try to avoid attacks from males

 Brittany Dean, Kayley Evans, & Jane Champion  Stevan Reneau, Gilroy Welch, & Birds Without Borders  Dr. Tak Fung  Natural Sciences and Engineering Research Council of Canada, University of Calgary, & National Geographic

XY = total number of males and females sampled k = total number of subgroups sampled i = selected subgroup N i = subgroup size X i Y i = number of males and females is a subgroup