DISSERTATION RESEARCH: Kin Favoritism and Communal Nesting

亲属偏袒和集体筑巢。沃伦·霍姆斯斯蒂芬妮·杰西这个实验室和实地研究相结合的项目将调查一种群居的南美啮齿动物德古的亲属识别和裙带关系。野外证据表明，雌性Degus是共同筑巢的，这意味着两只或更多的雌性共享一个洞穴，两只雌性都在这个洞穴中哺育它们的后代。由于集体筑巢和出生同步，德古妈妈会遇到并熟悉不是自己后代的幼崽。同样，幼崽从出生起就会与兄弟姐妹和非兄弟姐妹互动。一般来说，如果母亲和她的子女与他人共享早期的抚养环境，从而破坏了养育关系和亲属关系之间的相关性，那么简单的“熟悉”不太可能解释歧视性的产妇护理或兄弟姐妹的裙带关系。在之前的工作中，圈养的德古犬妈妈区分自己幼崽的气味和共同筑巢伙伴产生的气味，尽管这两种幼崽都生活在一起。建议进行三项后续实验室研究，以调查亲属关系和共同抚养如何影响产妇护理和兄弟姐妹关系。首先，将确定共同筑巢的母亲是否优先喂养自己的幼崽。将观察母亲对自己和其他孩子的行为。不同的乳汁转移也将通过给母亲注射少量的辐射(从而给她们的乳汁贴上标签)并测量幼崽粪便中的辐射量来确定。其次，食品质量将被操纵，以评估营养如何影响护理偏好。将使用与之前的实验相同的行为观察和牛奶标签技术。第三，我将研究青少年的社会偏好，特别是玩伴偏好，以确定共同成长和亲属关系如何影响社会发展。还将在智利大学的实地考察站Quebrada de la Plata进行几项实地研究。目前尚不清楚野外的德古母是否共用同一个产房，尽管它们拥有相同的洞穴系统。因此，拟议的实地工作的第一部分将包括使用无线电遥测技术监测共巢母亲，以确定它们在分娩前和/或分娩后是否共用地下洞穴。野外同巢雌性的遗传关系也是未知的。因此，将从自由生活的迪格斯采集小组织样本，对DNA进行遗传分析，以确定共享同一洞穴的雌性恐龙的血缘关系。还将进行行为观察，以检验争斗和友好行为如何随关联度的变化而变化。这项研究将揭示亲属识别和裙带关系是如何在一个群体生活的物种中起中介作用的，在这个物种中，“简单的”熟悉不足以代表亲属关系。

Kin Favoritism and Communal NestingDr. Warren HolmesStephanie JesseauThis combined laboratory- and field-research project will investigate kin recognition and nepotism in a communally-nesting, South American rodent, the degu (Octodon degus). Field evidence suggests that female degus nest communally, which means that two or more females share a burrow in which both females rear their litters. Due to communal nesting and birth synchrony, degu mothers encounter and become familiar with pups that are not their own offspring. Similarly, pups interact with both their siblings and non-siblings from the time they are born. In general, if a mother and her offspring share an early rearing environment with others, thus contaminating the correlation between rearing association and kinship, simple "familiarity" is unlikely to explain discriminative maternal care or sibling nepotism. In prior work, captive degu mothers discriminated between the odors of their own young and those produced by their co-nesting partner despite having lived with both kinds of pups. Three follow-up laboratories studies are proposed to investigate how kinship and being reared together affect maternal care and sibling relationships. First, it will be determined whether co-nesting mothers preferentially nurse their own young. Observations will be made of mothers' behavior toward their own vs other offspring. Differential milk transfer will also be determined by injecting mothers with small amounts of radiation (thus labeling their milk) and measuring the amount of radiation in the pups' feces. Second, food quality will be manipulated to evaluate how nutrition affects nursing preferences. The same behavioral observations and milk-labeling techniques as the previous experiment will be used. Third, I will examine juveniles' social preferences, specifically play-partner preferences, to determine how growing up together and kinship affect social development. Several field studies will also be conducted at Quebrada de la Plata, the field station of Universidad de Chile. It is not known whether degu mothers in the wild share the same natal chamber even though they occupy the same burrow system. Therefore, the first portion of the proposed field work will consist of monitoring co-nesting mothers using radio telemetry to determine if they share underground burrows before and/or after they give birth. The genetic relationship of co-nesting females in the wild is also not known. Therefore, small tissue samples will be taken from free-living degus to perform genetic analyses of DNA to determine the kinship of females sharing the same burrow. Behavioral observations will also be made to examine how agonistic and amicable behaviors vary with relatedness in degus. This study will reveal how kin recognition and nepotism are mediated in a group-living species in which "simple" familiarity is an inadequate proxy for kinship.