Woodley S K, Moore M C
Department of Biology, Arizona State University, Tempe, Arizona 85287-1501, USA.
Horm Behav. 1999 Jun;35(3):205-14. doi: 10.1006/hbeh.1999.1514.
Females are aggressive in many species but relatively little is known about the hormonal basis of female aggression, especially in free-living animals. Female mountain spiny lizards aggressively defend territories from other females. Previously, we showed that plasma levels of testosterone (T) and estradiol (E) are positively associated with levels of female aggression. Here, we manipulated hormone levels in free-living females and examined aggression expressed by females returned to their natural territories. Females received one of the following: (1) ovariectomy + empty implant (OVEX), (2) ovariectomy + T implant (T-IMP), or (3) sham surgery + empty implant (SHAM). OVEX females had reduced plasma levels of E but not T relative to SHAM females. T-IMP females had elevated plasma levels of T. Levels of display and aggression in OVEX females were reduced relative to SHAM females. T-IMP females had restored levels of display behavior although, unlike SHAM, no T-IMP females expressed the overt aggressive behavior of charging. These data are most consistent with the hypothesis that an ovarian factor such as E promotes female aggression, since ovariectomy reduced both plasma E and aggression but had no effect on plasma T. The results from the T-IMP females are also consistent with this hypothesis if we assume that the effects of T are due to aromatization to E in target tissues. The data do not rule out a role for T in promoting female aggression since T-implants resulted in elevated plasma T and restored display behaviors. This study represents one of the first studies examining the hormonal basis of female aggression in free-living females.
在许多物种中，雌性具有攻击性，但对于雌性攻击行为的激素基础，我们了解得相对较少，尤其是在自由生活的动物中。雌性山地多刺蜥蜴会积极地保卫自己的领地免受其他雌性的侵犯。此前，我们发现血浆中的睾酮（T）和雌二醇（E）水平与雌性攻击行为的程度呈正相关。在此，我们对自由生活的雌性蜥蜴的激素水平进行了调控，并观察了回到自然领地的雌性蜥蜴所表现出的攻击性。雌性蜥蜴接受了以下处理之一：（1）卵巢切除 + 空植入物（OVEX），（2）卵巢切除 + T植入物（T - IMP），或（3）假手术 + 空植入物（SHAM）。与SHAM组雌性相比，OVEX组雌性的血浆E水平降低，但T水平未降低。T - IMP组雌性的血浆T水平升高。与SHAM组雌性相比，OVEX组雌性的展示和攻击行为水平降低。T - IMP组雌性的展示行为水平恢复，不过与SHAM组不同的是，没有T - IMP组雌性表现出明显的攻击行为——冲锋。这些数据与以下假设最为一致：诸如E这样的卵巢因子促进雌性攻击行为，因为卵巢切除降低了血浆E水平和攻击行为，但对血浆T水平没有影响。如果我们假设T的作用是由于在靶组织中转化为E，那么T - IMP组雌性的结果也与该假设一致。这些数据并不排除T在促进雌性攻击行为中的作用，因为T植入导致血浆T水平升高并恢复了展示行为。这项研究是最早研究自由生活雌性动物攻击行为激素基础的研究之一。
