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

Abstract

Territorial behaviour in female small mammals has been proposed as a mechanism to defend limited ecological resources or their pups against conspecific infanticidal or predators. Female territorial behaviour very often is associated with reproductive activity due to the fact that frequency and intensity of aggression are exhibited mainly when females are pregnant or lactating. In vole and mice species, female territoriality would be a counterstrategy to prevent the killing of their pups by conspecific breeding females. To study whether female territoriality is a strategy for pups or nest defence against infanticidal breeding females, and whether time invested in nursing young affects aggressive response of mothers, we used the Pampean grassland mouse (Akodon azarae) as an ecological model species. We conducted resident–intruder tests between lactating females. Differences in residency time (48 vs. 72 h) of focal females in their home territory were also included in the analysis. In all cases, the pups of both resident and intruder mothers were placed with the nesting material from their reproductive cages. Resident mothers were always more aggressive than intruders and they were even more aggressive when they spent more time nursing their pups. Contrarily, intruder females exhibited the greatest values of submissive behaviours. Our results show that female territoriality of A. azarae would represent a strategy to protect pups from potentially infanticidal females. We discuss the extent of female intrasexual territoriality and its potential adaptive significance in relation to strategies which lead to increase their reproductive success.

INTRASPECIFIC KILLING EVENTS IN SIGMODONTINE RODENTS (Oecomys cf. cleberi AND Oligoryzomys nigripes)

“…Despite extensive literature on intraspecific agonistic behaviors for rodents of the Northern Hemisphere (e.g., Sadleir 1965, Scott 1966, Munger & Brown 1981, Wolff et al 1983, Petersen & Helland 2015, Blocker & Ophir 2016, few studies have been conducted on sigmodontine rodents (e.g., Courtalon et al 2003, Steinmann et al 2009, Bonatto et al 2013a, Petersen & Helland 2015, Bonatto et al 2017. Furthermore, this is the first study that reports intraspecific killing in free-living sigmodontines trapped in the same live-trap.…”

O papel de machos e fêmeas e a variação temporal na defesa de territórios na choca-de-asa-vermelha (Thamnophilus Torquatus)

“…Por outro lado, um estudo com o tiranídeo Myrmeciza longipes demonstrou que, apesar da defesa conjunta do território ocorrer ao longo de todo o ano, a escassez sazonal de recursos favorece uma maior agressividade por parte de ambos os sexos, especialmente quando ocorre a invasão do território (Fedy;Stutchbury, 2005). Outros estudos indicam também que fêmeas apresentam variação sazonal na intensidade da defesa do território, aumentando a territorialidade durante o período reprodutivo (Bonnatto, 2017). Além disso, existem registros de defesa de território individual por parte das fêmeas, como no caso do Passeriformes Malurus cyaneus, na qual elas defendem o território na ausência dos parceiros (Cooney;Cockburn, 1995).…”

Genetic structure of populations of the Pampean grassland mouse, Akodon azarae, in an agroecosystem under intensive management

“…In summer, female SGS patterns showed no structuring. A. azarae breeding females are aggressive against female intruders as a strategy to protect their offspring from potentially infanticidal females and that intensity of aggressiveness increases with increasing residence time of the defending female (Bonatto et al, 2017). If we consider that in this season the population density begins to increase, that the proportion of juveniles increases as observed in this work and in other studies (Zuleta et al 1988; Zuleta and…”