Behavioral Basis of Shared Paternity in the Striped-backed Wren

一种成功的动物(在进化意义上)是这样一种动物，它的行为是为了在后代中最大限度地表现自己的基因。因此，一只动物可以像通常发生的那样通过饲养自己的后代来成功，也可以通过帮助饲养与自己密切相关的后代来获得成功，就像大多数“合作繁殖者”所发生的那样。例如，在一对交配的鸟巢中的成年帮手经常帮助他们的父母抚养他们的后代，这些后代是他们自己的完全兄弟姐妹。在委内瑞拉的条纹背乌鸦中，在一个特定的社会群体中长大的雄性和雌性在成熟后会成为同一群体中的帮手。由于死亡率很高，死亡的主要雌性被与该群体无关的移民雌性所取代，帮助者经常帮助抚养作为他们同父异母的兄弟姐妹的幼崽。因此，一位占主导地位的女性的死亡和她被移民取代，对男性帮手来说是一件大事。他的母亲的去世(1)突然减少了他通过帮助抚养占主导地位的一对的后代(因为雌性不再是他的母亲)而享有的遗传利益，以及(2)为他创造了一个机会，通过与新的占主导地位的雌性交配，非乱伦繁殖。最近的行为研究表明，男性帮手经常追求并试图追求与自己无关的占主导地位的女性，只是被占主导地位的男性阻止与占主导地位的女性交配。DNA指纹技术是一种用于分配亲子关系的分子技术，它显示，在所有幼崽中，有15%的幼崽来自与占主导地位的雌性没有亲缘关系的男性助手的群体中，他们是男性助手和占主导地位的雌性的后代。剩下的85%是占主导地位的一对的后代。派珀博士的研究项目将更详细地比较男性帮助者的行为，这些男性帮助者是占主导地位的女性的儿子，而那些与她无关的人是男性帮助者。具体而言，他会研究男佣与占主导地位的女性交往的倾向、占主导地位的男性对男佣的待遇，以及男佣给予父母的照顾程度。这项研究将增加我们对合作饲养动物中的帮助行为和乱伦避免的理解，更广泛地说，将有助于对帮助行为的演变的洞察。

A successful animal (in the evolutionary sense) is one that behaves so as to maximize the representation of its genes in future generations. Therefore, an animal can be successful either by raising its own offspring, as usually occurs, or by helping to raise offspring that are closely related to itself, as occurs in most "cooperative breeders." For example, adult helpers at the nests of mated pairs of birds are often helping their parents raise offspring that are their own full siblings. In the stripe-backed wren of Venezuela, males and females raised in a given social group become helpers in the same group when they mature. Since the mortality rate is high and dominant females that die are replaced by immigrant females unrelated to the group, helpers often help raise juveniles that are their half siblings. Thus, the death of a dominant female and her replacement by an immigrant is a significant event for a male helper. His mother's death (1) suddenly decreases the genetic benefit he enjoys by helping to raise offspring of the dominant pair (since the female is no longer his mother) and (2) creates an opportunity for him to reproduce non-incestuously by mating with the new dominant female. Recent behavioral research revealed that male helpers routinely pursue and attempt to court dominant females unrelated to them and are only kept from mating with dominant females by dominant males. DNA fingerprinting, a molecular technique used to assign parentage, has shown that 15% of all juveniles from groups that contain male helpers unrelated to the dominant female are offspring of male helpers and dominant females. The remaining 85% are offspring of the dominant pair. Dr. Piper's research project will compare in more detail the behavior of male helpers that are sons of the dominant female and those that are unrelated to her. Specifically, he will examine the tendency of male helpers to associate with dominant females, the treatment of male helpers by dominant males, and the amount of parental care given by male helpers. This study will increase our understanding of helping behavior and incest avoidance in cooperatively breeding animals and, more generally, will give insight into the evolution of helping behavior.