配偶数增加对布氏田鼠社会行为的影响

为研究配偶数量对布氏田鼠 (Microtusbrandti)社会行为的影响 ,设置了 6组处理方法 :对照组 1♂+1♀配对组 ,只增加雌性配偶的 1♂ +2♀处理组和 1♂ +3♀处理组 ,只增加雄性配偶的 2♂ +1♀处理组和 3♂ +1♀处理组以及同时增加雌雄配偶的 2♂ +2♀处理组。每个处理各设 10个重复。记录各实验组中布氏田鼠在观察箱内 (两个大小为 37cm× 2 7cm× 17cm的有机塑料箱合并而成 ) 10min内发生的非对抗行为频次和对抗行为频次。结果表明 :与对照组相比 ,其它各组布氏田鼠的非对抗行为频次都明显降低 ,而对抗行为频次都明显增加。有效性比和密度与布氏田鼠社会行为的相关性研究表明 ,配偶数增加主要通过密度的改变来影响布氏田鼠的社会行为 ,配偶数增加引起密度的升高 ,密度的升高导致布氏田鼠社群内非对抗行为显著减少 ,对抗行为显著增加 ,从而引起布氏田鼠社群关系的紧张 ,加大了社群的竞争强度.     

自由生活的橙腹田鼠中是否有配偶选择?来自野外数据的证据

使用在长期研究橙腹田鼠的社会组织中收集的数据 ,我们研究了该物种配对的形成和解体。大多数在春季形成的配对包括了各公社群 (包括至少两个同性个体的群 )过冬后的生存者。无论雌、雄个体是否来自相同或不同的的公社群 ,配对的个体都不是同一家庭的成员。春秋季形成的新配对 ,通常包括一直在研究地游荡的无亲缘关系的个体。所以 ,我们的野外数据表明 ,橙腹田鼠避免与家庭成员配对 ;但是没证据表明自由生活的橙腹田鼠以体重为基础来进行配偶选择 ,也没证据表明在野外或半自然的实验室条件下 ,雌性个体偏好有性经历的雄性个体。在我们研究的种群中 ,配对分离的个体都具有一个特征 ,即分离前的繁殖成功率比未分离的配对个体低。在任何特定的时间内 ,由于雌、雄性个体的潜在配偶的数量有限 ,所以 ,几乎没有个体有机会同时比较两个或更多潜在配偶的特征。结果表明 :我们所研究的种群中的配对是机会主义式的 ,个体与第一个能得到的配偶形成配对关系     

亲缘关系与布氏田鼠双亲行为和杀婴行为关系的初探

根据幼仔发育的 5个阶段 :新生 (1～ 5日龄 )、耳立 (6～ 9日龄 )、睁眼 (10～14日龄 )、出巢 (15～ 2 0日龄 )和断奶 (2 1～2 4日龄 ) ,通过观察布氏田鼠对自己幼仔 (r=0 5 0 )和非亲缘幼仔 (r <0 12 5 )的行为反应 ,研究亲缘关系对布氏田鼠双亲和杀婴行为的影响。结果表明 :1)新生阶段 ,雄鼠抚育亲仔的时间显著多于非亲缘幼仔 ;断奶阶段 ,雄鼠与亲仔相触及在巢内活动的时间也显著多于非亲缘幼仔 ;雄鼠在耳立、出巢和断奶阶段嗅闻非亲缘幼仔 ,以及在新生和睁眼阶段修饰非亲缘幼仔的时间都显著多于亲仔。 2 )断奶阶段 ,雌鼠与亲仔相触的时间显著多于非亲缘幼仔 ,但在睁眼阶段修饰非亲缘幼仔 ,以及在新生、耳立和出巢阶段嗅闻非亲缘幼仔的时间显著多于亲仔。 3)雌雄鼠在15日龄前没有杀婴行为 ,15日龄后 ,开始对非亲缘幼仔发生杀婴行为 ;雌鼠杀婴行为受幼仔发育的显著影响 ,且杀婴频次显著高于雄鼠 ;雌鼠在断奶阶段对非亲缘幼仔的杀婴频次显著高于亲仔。综上所述 ,亲缘关系对布氏田鼠的双亲和杀婴行为有显著影响 ,这可能与个体间的已往经历 (熟悉性等 )或表现性匹配等辨别机制有关。     

田鼠亚科啮齿动物的社会组织、交配制度和栖息地的关系

田鼠亚科的两种啮齿动物黄腹田鼠(prairie vole,Microtus ochrogaster)和草甸田鼠(meadow vole,M.pennsylvanicus)是社会组织完全不同的两个种。黄腹田鼠原始栖息地在北美北部中央大片毗连的草原上,生境较稳定。该种易于接触,其交配为一夫一妻制,并成对结合。雌雄鼠共居在同一巢穴里,雌鼠只与配对雄鼠交配,雄鼠回避非配对的外来雌鼠,并分担巢穴的营造和维修,同时也照管幼仔,包括饲养、聚集和挽救。幼体断乳后,多数仍留在巢穴里,并协助照管下一窝幼仔,不参加繁殖,只有那些从家族群中扩散出去,并与无亲缘关系的雄鼠交配的雌性青年鼠才能繁殖后代。这种交配制度的作用是扩散种群,子代为寻求婚配而从家族群中离去,从而避免局部种群密度增高,以及由此造成的食物短缺。由于繁殖对是由非亲缘关系的个体结合而成,避免了近亲繁殖及由此带来的遗传性有害影响。     

棕色田鼠的配偶选择和相关特征

为了确定野外生态研究中对棕色田鼠婚配制度为单配制的预测,在实验室观察记录了棕色田鼠的配偶选择箱内对配偶鼠（与选择鼠交配刚生过仔,雌鼠产后动情）与陌生鼠、熟悉鼠（雌雄田鼠山居一段时间后,开始进行交配）与陌生鼠的选择,发现棕色田鼠访问、追逐、嗅闻、爬胯配偶鼠和熟悉鼠以及与配偶鼠和熟悉鼠交配和相伴的时间明显地多于对 陌生鼠,而且攻击陌生鼠的时间明显多于配偶鼠和熟悉鼠（Wilcoxon检验,P＜0.05）。结果表明：雌雄棕色田鼠特异性地选择配偶鼠和熟悉鼠,对陌生鼠表现出较多的排斥,从而在配偶选择上呈现单配制特征。通过统计计算棕色田鼠社会组织特征和室内的个体形态、幼仔发育、交配行为、双亲育幼行为、社交倾向等参数,然后把这些参数和婚配制度较明确的草原田鼠、松田鼠、山地田鼠、草甸田鼠的相关数据进行比较,发现它与多配制种类差异较大,而与单配制的田鼠各类相似,通过以上实验分析结果推断棕色田鼠的婚配制度可能呈单配制,和野外生态研究的推测相一致。     

幼体生长发育特征可导致橙腹田鼠的单配体制吗?

橙腹田鼠(Microtus ochrogaster)和草原田鼠(M. pennsylvanicus)是两种亲缘关系很近,但有着完全不同交配体制的田鼠。本文试图通过他们头骨的形态学比较来验证幼体生长发育(paedomorphosis)可以印证单配制交配体制进化的假说。通过几种头骨的测量,我们发现草原田鼠头骨的长与宽比例大于橙腹田鼠,说明前者具有相对狭长的头骨。进一步的测量发现,这种不同是由于草原田鼠具有相对较长的鼻骨造成的。最后,我们对同种内成年和幼年的头骨进行了比较,发现单配制的橙腹田鼠相对于多配制的草原田鼠,其成年的头骨与幼年的头骨更相似。这些测量结果说明与多配制的田鼠相比,单配制的田鼠在形态及行为上保留更多的幼年状态,而这种行为很可能与其交配体制有关。     

熟悉性对棕色田鼠和根田鼠择偶行为的影响

以两性配对共居至交配或生仔作不同熟悉处理,在Y字型选择箱中分别观察棕色田鼠、根田鼠的择偶行为和配偶识别.结果如下:(1)棕色田鼠雌雄两性均表现出对熟悉异性或配偶的喜好倾向;(2)在根田鼠中,只有雌性表现出对熟悉雄鼠或配偶的选择倾向,雄鼠无明确的选择取向;(3)每种雌性田鼠对2种熟悉性不同的同种雄性的嗅舔时间均有显著差异性,而每种雄性田鼠对2种熟悉性不同的同种雌性的嗅舔时间均无显著差异性.这些结果表明:(1)熟悉性对棕色田鼠择偶行为的影响大于对根田鼠的影响;(2)嗅舔时间差异可反映不同田鼠的配偶识别能力,熟悉性对棕色田鼠配偶识别能力的影响大于对根田鼠的影响;(3)2种田鼠配偶识别的性别差异的一致性,提示这2种田鼠的雌性配偶识别能力均强于雄性田鼠,而雌鼠的配偶识别能力可能取决于雌鼠受交配或分娩刺激的生理状态; (4)棕色田鼠室内所表现的择偶行为的两性熟悉性特征与其单配制有关,根田鼠所表现的择偶行为的雌性熟悉性特征与其一雄多雌制有关.     

雌雄同居对子午沙鼠情绪及下丘脑催产素表达的影响

雌雄同居是配偶关系形成的重要阶段,涉及到一系列生理和情绪的变化,对长期稳定的配偶关系形成具有重要意义。然而由于单配制动物模型较少,雌雄同居过程中的神经调控,尤其是两性差异仍不清楚。本研究以室内繁殖的子午沙鼠(Meriones meridianus)为研究对象,采用高架十字迷宫、强迫游泳和免疫组化法,探究雌雄同居对雌雄子午沙鼠的情绪变化及其相关脑区催产素表达的影响。结果表明：雌雄同居10 d后,在高架十字迷宫中,雌性沙鼠进入开放臂的频次显著减少(P <0.05),焦虑指数显著升高(P <0.05);在强迫游泳实验中,同居组雌性沙鼠停止游泳的频次和时间显著增加(P <0.05);同居组雌性沙鼠在下丘脑室旁核和视上核中的催产素表达水平显著升高(P <0.05)。然而同居组雄性的行为和催产素水平均没有出现显著变化,这可能与雌雄配偶关系形成过程中的两性不同步有关。综上,雌雄同居仅使得雌性子午沙鼠表现出焦虑样行为,且下丘脑催产素系统可能参与了该过程。     

根田鼠的熟悉性及其自然动情下的配偶选择

报道了在室内雌鼠自然动情条件下根田鼠两性个体配偶选择的3种熟悉性效应的5组实验结果,包括雌性对熟悉和陌生雄鼠、配偶和陌生雄鼠、配偶和熟悉雄鼠的择偶行为实验 , 雄性对熟悉和陌生雌鼠、配偶和陌生雌鼠的择偶行为实验。在实验前, 将1对性成熟的雌雄鼠 (非亲缘关系) 每天关养8 h 共8 d 建立熟悉性; 配对雌雄鼠至少生育1胎则为配偶关系。在 Y 形迷宫内的30 min 实验中, 两个被选择鼠分别以项链拴在横跨选择箱顶端中央的一根铁丝上, 限制它们在各自箱内活动; 而允许异性选择鼠从中立箱自由进入两个选择箱。记录选择鼠对异性被选择鼠的访问、社会探究、攻击、交配和友好行为的频次和时间。经Wilcoxon 关联样本 T 检验发现, 除交配行为不显著外, 雌性根田鼠均选择熟悉性较高的雄鼠; 而雄鼠不具这种选择性。该结果提示雌雄根田鼠的不同择偶行为也许就是反映该种婚配制度特征的直接行为过程。因此, 在择偶行为中, 雌性根田鼠表现的单配性倾向和雄鼠的多配性倾向, 只能以其婚配制度为一雄多雌制的假设来解释。我们的实验还说明在多配制田鼠中, 一雄多雌制与混交制在雌鼠择偶行为上是不同的, 而与单配制的相似或相近, 故简单地比较多配制与单配制则不能反映田鼠亚科动物婚配制度的多样性。     

哺乳期棕色田鼠对非亲缘幼仔的行为反应

通过观察产后2 日(L2)、6 日(L6)、10 日(L10)、14 日(L14)和20 日(L20)的棕色田鼠母鼠对2 日龄、6 日龄、10 日龄和14 日龄非亲缘幼仔的攻击行为和衔回行为,探讨了哺乳期棕色田鼠的母性行为与非亲缘幼仔的发育(日龄或个体大小)及母鼠产后时间的关系。结果表明,在哺乳前期(L2,L6),非亲缘幼仔的日龄大小显著影响母鼠的攻击行为(P < 0.05);在哺乳中期(L10,L14)及后期(L20),非亲缘幼仔的日龄对母鼠的攻击行为没有显著影响(P > 0. 05)。在整个哺乳期,母鼠对14 日龄非亲缘幼仔的攻击频次最高(P < 0.05)。产后不同时间的母鼠对同一日龄非亲缘幼仔的攻击频次没有显著差异(P > 0.05)。这些结果表明,哺乳期内的棕色田鼠对非亲缘幼仔的攻击与幼仔的发育有关,与母鼠的产后时间无关。     

Habitat saturation and communal breeding in the acorn woodpecker

The acorn woodpecker (Melanerpes formicivorus) typically lives in social groups that breed communally: all group members help to feed the young of a single nest. The behaviour of acorn woodpeckers was compared in two locations (New Mexico and California) to test the hypothesis that saturation of the habitat by established groups may lead to more than a single male-female pair living in groups during reproduction. Several lines of evidence indicated that the habitat was less saturated in New Mexico. This difference was reflected in a lower tendency for juveniles and adults to remain in groups, higher reproductive rates and, most important, smaller group sizes. These results suggest that habitat saturation plays an important role in communal breeding in this species.     

棕色田鼠洞群内社会组织

每月选取农田样方,用洞道内置夹及挖捕法对棕色田鼠洞群内的群体结构进行调查发现,棕色田鼠在不同的季节,洞群内个体组成不同。在4月和10月,同洞群内成年雄性和雌性的数量较多,往往有两个以上的雌性个体参与繁殖,而且亚成体和幼体的数量也较多;而6月至9月,棕色田鼠多呈雌雄一一配对,有些洞群内也有幼体和亚成体,雌雄共巢,而呈现单配制特征。所以其社会组织呈现群居家庭、双亲家庭和单亲家庭3种类型。4月和10月群居家庭最多（60%,61.53%）,6月和9月双亲家庭较多（80%,75%）,双亲家庭所占比例和密度呈负相关,而群居家庭所占比例和密度呈正相关。在不同的季节洞口系数不同,洞口系数和密度呈正相关。     

Demographic and reproductive patterns in moustached tamarin monkeys (Saguinus mystax): Implications for reconstructing platyrrhine mating systems

In this paper we address a series of questions concerning reproductive opportunities, kinship, dispersal, and mating patterns in free-ranging moustached tamarin monkeys (Saguinus mystax). Between 1980 and 1990 information on group size, composition, and migration patterns was collected on marked groups of moustached tamarins inhabiting Padre Isla, an island in the Amazon Basin of northeastern Peru. In 1990, 86% of 114 animals residing in 16 social groups were trapped, examined, and released. Mean group size was 7.0, including 2.2 adult males and 2.0 adult females. None of these groups was characterized by a single adult male-female pair. In groups with more than one adult female, only the oldest female produced offspring. An examination of dispersal patterns indicates that transfers between groups were common and fell into several categories, including immigration of individual males and females, simultaneous transfer of pairs of subadult and/or adult males (sometimes relatives) into the same social groups, and group fissioning in which males and females of the splinter group join another small social group. We have no unambiguous cases of 2 adult/subadult females migrating together into the same social group. All 6 groups for which reproductive data were available were characterized by either a polyandrous or polygynous (polygyandrous) mating pattern. The results of this study indicate that moustached tamarins reside in small multimale multifemale groups that are likely to contain both related and unrelated adult group members. Kinship and social ties among males appear to be stronger and more longlasting than kinship and social ties among females. We contend that the modal mating system of moustached and many other tamarins is not monogamous, and offer the possibility that cooperative infant care and mating system flexibility in callitrichines evolved from a polygynous mating pattern. © 1993 Wiley-Liss, Inc.     

Fitness consequences of sociality in prairie voles, Microtus ochrogaster: influence of group size and composition

We used 7 years of live-trapping data from an Illinois population of prairie voles to examine how survival and reproductive success varied with size and composition of social groups. Specifically, we examined measures of fitness for residents of single female units, male-female pairs and communal groups. Reproductive success, measured as either the number of young that survived to 12 or 30 days of age per adult female in a group, was higher for groups of three adults than for smaller or larger groups. The ideal group composition with respect to reproductive success appeared to be one adult female and two adult males. Individuals born into groups with three adults survived longer than did those born into smaller or larger groups. There was no clear relationship, however, between group size and survival of adult members of groups. Sudden disappearance of a group, presumably to predation by weasels, was associated with relative group size such that the largest groups were more likely to disappear. Overall, our data indicate that prairie voles living in communal groups with three adult members have higher fitness than those living in smaller groups or in larger communal groups. Copyright 2002 The Association for the Study of Animal Behaviour. Published by Elsevier Science Ltd. All rights reserved.     

Southern Lapwing Vanellus chilensis cooperative helpers at nests are older siblings

Cooperative breeding is rare in shorebirds, and when found it is thought to be due to polygamous mating (cooperative polygamy). Here we describe the social structure of cooperatively breeding groups in Southern Lapwing Vanellus chilensis and test the prediction that offspring sex ratio is skewed towards the sex that helps. The social groups consisted of a breeding pair with one or two young (mostly males, 68%) from the previous breeding season, and offspring sex ratio was not skewed. Cooperative breeding in the Southern Lapwing is not the consequence of cooperative polygamy, but rather groups were formed by a mated pair and some of their offspring from previous nests as helpers.     

Social relationships of immigrant and resident female mountain gorillas. I. Male-female relationships

Adult males are important social partners for all females in mountain gorilla social groups, but male-female relationships can vary in association with variation in female residence status, male age and mating status, and relatedness. Such variation occurred in a large group observed over a 3-year period. All females associated and interacted affiliatively relatively often with a young silverback with whom all mated. Long-term resident females also did so with an old, non-breeding male to whom most were related, but recent immigrants spent little time near him and had few non-aggressive interactions with him. The old male made agonistic interventions to support relatives; interventions in female conflicts by the younger male tended to ameliorate competitive differentials that immigrants faced and may have helped him to retain them as mates. Males aggression toward females was common, most probably served as a mating tactic, and did not involve resource competition. Extensive grooming by an adolescent male suggests that males may also use affiliative behavior to develop mating relationships. Females may have competed for proximity with and social access to the younger silverback; competitive success could influence how well females and their offspring are protected by silver-backs, but the extent of such competition was not clear. Large group size may have heightened differentiation of male-female relationships and competition among females, but comparative data from smaller groups generally corroborate the findings from the large group. © 1992 Wiley-Liss, Inc.     

Instability Rules Social Groups in the Communal Breeder Rodent Octodon degus

It has been hypothesized that animal groups in socially cohesive species are inherently unstable, ultimately the result of constraints to independent breeding, and proximately the product of adult fidelity and offspring philopatry. Other processes, including emigration of individuals that join pre-existing groups would be less important. We examined the persistence and variation in the composition of members of social groups in Octodon degus , a communal breeding rodent in which limitations to independent breeding are less obvious. This analysis was conducted during subsequent years, as well as during different seasons within years. Similar to social species in which constraints to independent breeding influence sociality, groups in degus were unstable in that they were short lived and ruled by an extensive turnover of group members across years. A relatively high turnover of group members was also recorded within years. Variation in the composition of groups was caused mostly by disappearance (presumably mortality) and immigration of adult members. Adult fidelity and offspring philopatry and dispersal played secondary roles in affecting the composition of social groups between and within years. Future studies should reexamine the importance of habitat limitations and its proximate determinant, natal philopatry, in driving the stability of social groups.     

Aspects of the Social Ethology of Some Kalahari Rodents

Studied the social structure of nine rodent species in a subdesert environment by means of direct observation and live- and snaptrapping. Six social groupings — asocial, solitary dispersed; social, solitary clustered; social, communal pair; social, communal but non-colonial; social, communal with little contact; social, communal with close contact (colonial) — are recognized. Diurnal species tend to live in colonies, probably with mutual warning systems against predators. For most species the social structure exhibited is an adaptation to predation, with the effect of food requirements playing a subsidiary role. Larder hoarding is common in solitary and asocial species.     

Social Relationships among Males in Multimale Siamang Groups

I quantified social and spatial interactions among adults in 4 multimale siamang (Symphalangus syndactylus) groups to evaluate the importance of aggression and avoidance in mediating male-male relationships. Actual genetic relationships among adults are unknown, but available mitochondrial data suggest that in 3 of 4 groups, neither male was the offspring or maternal sibling of the female, whereas in the fourth group, a matrilineal relationship between the female and 1 adult male was not excluded. Rates of aggression involving male-male dyads were very low. One male-female dyad maintained closer spatial cohesion than those of other adult dyads in 3 of 4 groups. Nonetheless, all adult males spent substantial percentages of their time ≤20 m from other adults in their groups. The percentages of time that male-male dyads spent in social grooming interactions did not differ from those of male-female dyads. In 3 groups, both males copulated with the group female. While previous studies have reported high rates of aggression between adult males and subadult male group members in siamangs, my results suggest that male-male relationships in multimale groups at Way Canguk were relatively harmonious. Acceptance of multimale grouping (and in some cases sexual polyandry) suggests that the benefits outweigh the costs under some circumstances. If there was a genetic relationship between males, then tolerance of delayed dispersal and copulation with the adult female may function as a form of parental investment. Males may also benefit from multimale grouping via enhanced territorial defense or reduced costs of mate defense.     

Do sire-dam interactions contribute significantly to fertility comparisons in heterospermic insemination trials

The percentage of offspring sired after heterospermic insemination of equal numbers of spermatozoa is believed to be a very sensitive measure of relative in vivo fertility of the inseminated samples. The objective of these trials was to evaluate whether there was a detectable male-female interaction in the fertilizing ability of spermatozoa. If there was such an interaction, we reasoned that the paternity of offspring from individual females in a heterospermic trial the second year would be similar to the paternity of offspring in the same individual females the first year if the same ejaculates were used. Five groups of ewes were inseminated with different combinations of semen (a single Merino ejaculate from one of five rams randomly paired with five different pools of Suffolk semen) in a heterospermic trial. Those ewes conceiving the first year were inseminated in a second breeding season with the same combination of semen used previously. The percentage of lambs sired by each ejaculate/pool of ejaculates was calculated for all lambs born from all ewes inseminated with each semen combination. These percentages would be the expected ratios of Merino-sired:Suffolk-sired lambs if there is no male-female interaction. Ewes in each group were divided into two subgroups: those conceiving only Merino-sired lambs the first year and those conceiving at least one Suffolk-sired lamb the first year. The ratio of Merino-sired lambs:Suffolk-sired lambs did not differ in either subgroup from those expected if there was no male-female interaction. These results are consistent with the absence of a male-female interaction in relative fertilizing ability of spermatozoa.