Behavioral effects of testosterone in relation to social rank in the male rabbit

Abstract

The role of gonadal androgens in favoring the adaptation to environmental pressure, including social organization, is well known. In the rabbit, testosterone administration increases marking behavior, and its level can be affected by agonistic interaction. In this experiment, we studied the effect of subcutaneous administration of testosterone propionate (TP) (3 mg/d for 6 days) in male rabbits belonging to the same social group (6 groups of 4 animals). In 2 additional groups (4 animals each), males were injected with almond oil. The animals were observed for 6 days in seminatural conditions, then treated with TP (or oil) and observed for another 6 days. The dominant/subordinate frequency ratio of behavioral patterns was used to rank the animals. The testosterone plasma concentration was correlated with agonistic behavior after the first period of social interaction. A significant increase of marking, digging, and defensive activity was observed after TP administration in all animals independent of rank, whereas this increase was not present in animals treated with oil. Agonistic and interactive behaviors increased significantly after TP treatment only in the first-ranking animals. This indicates the influence of social rank in the modification of behaviors involving interactions among subjects Aggr. Behav. 29:269-278,

Testosterone‐Mediated Effects on Fitness‐Related Phenotypic Traits and Fitness

“…3D). There is a general consensus that plasma T has positive effects on male sexual behavior (e.g., Marler et al 1995;Salvador et al 1996;Enstrom et al 1997;Briganti et al 2003), while the evidence is more ambiguous for sexual ornaments. This article further dem-onstrates that T not only modulates fitness-related behaviors that are important for both intra-and intersexual selection in the bank vole but also ultimately regulates reproductive success.…”

Personality in Non‐human Animals

“…Through techniques such as castration, injection, or capsule implantation, researchers are able to systematically study the relationship between hormones, biological processes, and behavior. For example, in one recent study, rabbits injected with testosterone increased their marking, digging, and defensive behaviors, but only the highest‐ranking rabbits in each social group increased in aggressive behavior; this finding suggests that testosterone has an effect on aggression in rabbits, but the effect is moderated by social rank (Briganti et al., 2003).…”

Long-term under-masculinization in male rabbits due to maternal stress is reversed by prenatal administration of testosterone

“…Nevertheless, the doses of TP used should have been sufficient to result in increased masculinization (rather than just overcoming the possible stress effect of administering the vehicle alone) if this is possible during early development. First, as mentioned in Methods, doses were based on reports in the literature for wild-type rabbits and from laboratory studies (Briganti et al, 2003;Chirino et al, 1993;González-Mariscal et al, 1993;von Holst, 1998). Second, TP was administered during the time window of reported sensitivity of male rabbits to the masculinizing effects of androgens (Ivanova, 1981(Ivanova, , 1978.…”

“…All groups except NIC received seven, once daily 0.5 ml injections on days 19-25 of gestation, between 09:00 and 10:00 h. The TP doses were not adjusted to body weight. The lower dose was chosen to correspond to the approximate levels of T reported for wild male rabbits (von Holst, 1998), and the higher dose corresponded to concentrations used in experiments reported in the rabbit literature (Briganti et al, 2003;Chirino et al, 1993;González-Mariscal et al, 1993).…”

“…In rabbits, serum levels of T are positively correlated with postnatal growth (Hudson et al, 2011) and are positively associated with agonistic behavior and social dominance in adults (von Holst, 1998). Dominance, in turn, is positively correlated with chin gland size and chin-marking activity (Arteaga et al, 2008;Black-Cleworth and Verberne, 1975;Farabollini, 1987;Girolami et al, 1998;Mykytowycz, 1965), and administration of T increases chin-marking in males whereas castration reduces or eliminates it (Briganti et al, 2003;Chirino et al, 1993;González-Mariscal et al, 1993;Martínez-Gómez et al, 1997).…”