Gonadal hormones and intrasexual aggressive behavior in female bank voles (Clethrionomys glareolus)

Abstract

The effects of gonadal hormones on aggressive behavior in the female bank vole was investigated in 10 min home cage tests. Ovariectomized (ovx) or intact females injected with oil, with progesterone (P), with a mixture of progesterone and estrogen (P+E), or with testosterone (T) alone were confronted in a resident-intruder test with unfamiliar, nonoperated females as intruders. Intact females showed aggressive behavior more frequently than ovx females. Ovx females injected with P, with P+E, or with T made significantly more attacks, and these attacks lasted longer than those observed for oil-treated voles. The results indicate that P, the typical female hormone, is responsible for aggressive behavior in female bank voles; however, only T increased the duration of interfemale aggression. Aggr. Behav. 24:63-70, 1998.

Egg yolk androgen levels increase with breeding density in the European Starling,Sturnus vulgaris

“…Although androgen levels are usually lower in females than in males, females do have circulating androgens that vary in concentration, depending on environmental conditions (Staub & De Beer 1997). In several mammalian species, female androgen levels are responsive to received aggression and activate expression of aggression (Siegel & Demetrikopoulos 1993;Staub & De Beer 1997;Kapusta 1998). Androgens activate female aggression in lizards as well (Woodley & Moore 1999;Rhen & Crews 2000).…”

Interfemale aggression in adult bank voles (Clethrionomys glareolus)

“…Immature or adult castrated animals exhibited lower aggression than adult males [Gipps, 1984]. In females, ovariectomy decreases the number of attacks, whereas injection of progesterone restores this behavior [Kapusta, 1998]. However, social factors play a crucial role in modifying behavior.…”

“…Aggression of bank vole females toward virgin females is linked to maternal behavior in late pregnancy as well as during early and mid-lactation periods, but different factors can control this behavior. Kapusta [1998] shows that progesterone stimulates aggression in virgin females; this suggests that a high level of this hormone can directly affect behavior during pregnancy. Lactating bank vole females were tested in the presence of their own pups, and in this case hormonal fluctuations as well as the presence of litters could stimulate attacks by mothers.…”

Territorial aggression by dwarf hamster females (Phodopus campbelli): A hormonal approach

“…Mating cages had the same characteristics as those in which they were housed after weaning. Afterward, a foreign female was introduced into the cage; this female intruder had a weight equal to or lower than the resident female (≤3 g) since the confrontation with a smaller opponent often promotes aggression (Cain & Ketterson, 2012; Koolhaas et al, 2013). The intruders were virgin females with an age range similar to the paired females and previously kept with 2–3 individuals per cage since weaning.…”

“…Aggression has been classified in different ways; Moyer (1971) ranked the conduct according to the social context in which it occurs, as maternal and territorial aggression. More recently, it was classified as offensive and defensive; the first one describes behaviors used for attack, whereas defensive aggression is the form of aggressive behavior performed in response to an attack by another individual (Koolhaas et al, 2013). Territorial aggression is one of the most studied types of this conduct, displayed when there is competition for resources such as territory, mating partners, or food, all of which can be present in a socio‐geographical area (Demas et al, 2007; Soma et al, 2015; Sousa & Casanova, 2006).…”