IIMYC   23581
INSTITUTO DE INVESTIGACIONES MARINAS Y COSTERAS
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Mother's protection: Sexual dimorphism of bite force in rats
Autor/es:
BECERRA FEDERICO; BEMMANN MAXIMILIAN; CAGAN ALEXANDER; KONOSHENKO MARIYA; KOZHEMYAKINA RIMMA; KUPCZIK KORNELIUS
Lugar:
Amsterdam
Reunión:
Congreso; XXI Zoology Congress; 2015
Institución organizadora:
Royal Dutch and Belgian Zoological Societies
Resumen:
Sexual dimorphism in bite force has been analyzed in several mammalianspecies in the contexts of sexual selection, niche differentiation and sourcecompetition. Yet, the mating system, social structure and maternal care mightbe also playing a special but previously overlooked role in a sex-biased bitingperformance as a defensive behavior. To test for sexual dimorphism in biteforce output we measured 19 rats Rattusnorvegicus (9 males, 10 females; 4 months old) originating from a wildderived breeding line which has been selected for aggressive behaviour towardshumans for over 70 generations. In addition, body size and overall headmeasurements were recorded. We observed that females displayed more aggressivebehavior than males. Results show that bite forces were higher both absolutely(F1,17 = 24.23, p < 0.01) and when corrected for body size (F1,16= 5.67, p = 0.03), but they were not predicted by either of the two analyzedcranial morphological parameters in females (head length: p = 0.42, mandibular width:p = 0.51), suggesting that it is behavior-dependent. This might be the reasonwhy, after scaling against these cranial parameters, sexual dimorphism was notsignificant anymore (FHL 1,16 < 0.01, p = 0.94; FMW 1,16= 0.30, p = 0.59). These results agree with previous observations on wildrodent species with differences in degree of sociality, in which bite forceswere relatively higher in males (solitary: Ctenomysspp) and females (social: Octodondegus), respectively. We propose that (A) due to altriciality, therelatively extended period of maternal care may have driven selection for anincreased propensity for defensive aggression in female rats, and (B)morphology alone can be insufficient to predict bite force in vivo and behaviormust also be taken into consideration to avoid misleading models.