Inter-male aggression with regard to polygynous mating system in Pampean grassland mouse, Akodon azarae (Cricetidae: Sigmodontinae)

Abstract

Based on the hypothesis that, in Akodon azarae, polygyny operates through female defence, we studied inter-male aggression in order to test the following predictions: during the breeding period (1) resident males are more aggressive than intruder males in the presence of females (FP), and (2) aggressive behaviour is independent of male condition (resident or intruder) in the absence of females (FA). To test our predictions, we used the resident male behavioural response towards an intruder male in relation to FP or FA. We conducted 30 encounters in FP and 27 in FA in 0.79-m 2 round enclosures placed in the Espinal Reservation. Our results support the prediction that, in FP, the intensity of aggressive behaviour exhibited by males varied in relation to resident or intruder condition. Resident males showed high levels of aggression towards intruders, and intruders exhibited the greatest values of submissive behaviours with residents. In FA, the intensity of aggressive behaviour did not vary in relation to resident or intruder condition. Both resident and intruder males exhibited low aggressive behaviour and inter-male encounters resulted mainly in non interactive behaviours. Our results support the hypothesis that, in A. azarae, the polygynous mating system operates through female defence.

Rapid effects of estrogens on behavior: Environmental modulation and molecular mechanisms

“…Not surprisingly, males who are mate guarding initiate and participate in more agonistic interactions with conspecific males than do males who are solitary [70, 71], indicating that sexual behavior and aggression are indeed two highly associated behaviors. Two important aspects of mate guarding are territory and resource defense, which are essential components of attracting and maintaining a mate [72, 73].…”

Female Intrasexual Territoriality and its Potential Adaptive Significance: The Pampean Grassland Mouse as an Ecological Model Species

“…; Steinmann & Priotto ; Bonatto et al. ,b). Trials were performed during one of the activity peak of the Pampean grassland mouse, between 09:00 and 11:00 h (Priotto & Polop ).…”

“…), Bonatto et al. (2013b) carried out an experimental study to test that female territorial behaviour is a strategy to guarantee these resources. Although the results of this study did not support interfemale territoriality as a strategy for defence of food and shelter, it did not provide evidence to reject outright female intrasexual territorial behaviour.…”

“…Bonatto et al. (2013b) proposed that an alternative explanation to territoriality of A. azarae females would be pups or nest site defence, rather than food and shelter defence. In small rodent species with altricial young, several authors have supported the hypothesis that territoriality fulfil a function of pups and nest site defence, rather than food defence (Wolff ; Agrell et al.…”

Sexual dimorphism across 3 stages of development in polygynous Artiodactyls is not affected by maternal care

“…Polygyny occurs in many mammalian orders: Chiroptera and Rodentia (Clutton-Brock 1989; Bonatto et al 2013), Lagomorpha (Rioja et al 2008), Perissodactyla (Clutton-Brock 1989; Renan et al 2015), Cetartiodactyla (Clutton-Brock 1989; Weckerly 1998), Carnivora (Kovacs and Lavigne 1986; Weckerly 1998; Lodé 2001), and Primates (Harcourt et al 1981; Clutton-Brock 1989; Leigh 1992, 1995; Weckerly 1998; Grueter and Van Schaik 2009). In polygynous mammals, mature males intensely compete for the control of females.…”