社会性昆虫级型和行为分化机制研究进展

社会性的出现是生物演化过程中的重要革新, 理解社会性的演化和调控机制具有重要的理论和实际意义。社会性昆虫的个体间有着明显的级型分化和劳动分工, 这有利于它们适应复杂的环境变化。理解社会性昆虫如何产生不同的形态、行为和生活史特性, 一直是进化和发育生物学的重要目标。随着测序技术的不断更新及生物信息学的快速发展, 已经有众多关于社会性昆虫级型和行为分化机制的研究报道。本文通过整理社会性昆虫研究的已有成果, 从环境因素、生理调控和分子机制等方面对社会性昆虫级型和行为分化机制相关研究进展进行了综述, 并对未来的研究方向做出了展望。根据现有证据, 社会性昆虫所生活的生物环境(食物营养、信息素、表皮碳氢化合物)和非生物环境(温度、气候等)均能直接或间接影响社会性昆虫级型和行为的分化; 保幼激素、蜕皮激素、类胰岛素及生物胺等内分泌激素和神经激素对社会性昆虫的级型和行为分化也有重要的调控作用; 此外, 遗传因素、新基因等DNA序列或基因组结构上的变化以及表观遗传修饰、基因的差异表达等基因调控机制均能不同程度地影响社会性昆虫的行为分化。本文建议加强昆虫纲其他社会性类群如半翅目蚜虫和缨翅目蓟马等的社会性行为及其演化机制的研究, 以加深对社会性昆虫起源及其行为演化的理解和认识。     

社会性昆虫的组织及通讯行为

社会性昆虫在自然界有很重要的生物学意义,社会性昆虫具有3个主要特征,真社会性昆虫包括全部蚂蚁、白蚁及部分胡蜂、蜜蜂。它们具有明显的等级分化和个体分工。通过报警、集聚、化学招引、摇摆舞等方式,社会性昆虫在其内部做了很好的通讯交流从而使其社会组织得到了很好的发展。     

昆虫植食对植物有性生殖的影响

植物在个体发育的各个阶段都与不同的群落成员相互作用,如竞争的植物、有益的传粉者和敌对的植食动物。昆虫植食在各类生态系统中普遍存在,并可能对植物有性生殖产生各种影响。植食昆虫可通过对植物有性生殖结构的消耗直接对植物生殖产生影响,也可通过影响植物资源分配和花性状等改变传粉者服务,从而间接对植物有性生殖带来正面、负面或中性的影响。同一植物的植食昆虫和传粉者往往对植物的吸引性状 （如花大小、气味、颜色等）有相同的偏好,因此植食者与传粉者均能对植物有性生殖性状施加选择压力。本文从昆虫植食对植物有性生殖的直接影响、间接影响以及植食昆虫对植物有性生殖性状选择的影响三个方面进行综述,以期为昆虫植食和生物资源多样性保护相关研究提供参考。     

水生昆虫幼虫取食行为研究进展

作为生存的重要行为,水生昆虫幼虫的取食是水生昆虫行为学研究的重点.本文综述了水生昆虫幼虫的取食习性、取食机理、取食行为、消化过程和取食影响因素等方面的研究进展,指出了今后应深入研究水生昆虫取食机理,以促进水生昆虫行为学研究,进一步为人工繁育水生资源昆虫提供理论支持.     

社会性蜂类昆虫认知行为研究进展

关于动物认知研究主要侧重于大脑相对较大的脊椎动物,如灵长类和鸟类。本文综述了社会性蜂类个体、群体水平认知相关的研究工作。研究表明蜂类昆虫也具有复杂的个体认知能力,包括联想学习、自我认知、工具使用和空间导航等。蜂类昆虫表现出基于多巴胺的情绪状态,这种情绪是由对食物的欲望和个体经历引起的。蜂类昆虫同样还具有复杂的社会认知行为,蜂群中不同个体间能够进行个体识别,这是蜂群内部进行社会互动的基础。此外,部分蜂类被证实通过训练之后能解决一些非自然任务的能力,这些行为可以通过社会学习在不同个体间传播,最终在整个种群中保留下来。本文最后讨论了蜂类昆虫认知行为的神经基础,越来越多的证据表明蜂类昆虫具备认知能力的神经细胞基础,这取决于神经元之间的复杂连接。本文回顾了蜂类昆虫认知行为的最新进展,这有助于为动物行为和认知演化提供独特的视野。     

社会性昆虫社会身份识别机制研究进展

昆虫社会身份识别是指昆虫通过感知各种信息来辨别其他个体的身份,进而建立一定社会关系的生物学现象。社会身份识别对社会性昆虫的信息交流、天敌防御、社会分工、个体及群体生存和繁衍尤为重要。本文以蚂蚁、白蚁和蜜蜂等社会性昆虫为例,详细阐述了社会性昆虫的社会身份识别机制：社会性昆虫以信息素为关键线索,利用嗅觉实现社会身份的识别;社会性昆虫也通过其视觉观察同伴或天敌等个体的行为,实现社会身份的识别;社会性昆虫还能够识别特殊的声音信号和感知空气中的震波,并作为其社会身份识别的重要依据。此外,研究表明昆虫共生菌也参与调控社会性昆虫的身份识别。针对社会性昆虫身份识别是先天还是后天形成的这一争论,我们从基因、适应学习以及基因和环境互作等方面,阐述了昆虫可能通过先天遗传和后天学习相结合的方式实现社会身份识别的观点。社会性昆虫是研究人类和动物社会行为学的绝佳模式生物。社会身份识别的研究成果不仅可深入解析社会性昆虫的生物学特性,也对人类及其他动物的社会认知进化以及各类社会问题的研究提供重要参考。今后应加强以下两方面的研究：(1)探索社会性昆虫多样的识别方式,解码其更深层次的机制研究;(2)应用现代新型计算机技术,将社会性昆虫身份识别行为可视化分析。     

非编码RNA调控真社会性昆虫品级分化和个体分工的研究进展

真社会性昆虫是最具代表性的表型可塑性的研究对象之一,其个体之间分工协作的社会性生活方式增强了整个群体的环境适应性和繁殖力。真社会性昆虫虽然具有相同的遗传背景,个体之间却表现出明显的品级分化和个体分工,这是由环境和遗传共同影响的。表观遗传被认为是应对环境条件下重塑基因表达的主要机制,非编码RNA作为一类广泛参与机体生命活动的不编码蛋白的功能性RNA,在真社会性昆虫的品级分化、个体分工等方面起着重要的调控作用。本文从微小RNA、长链非编码RNA、环状RNA、与PIWI蛋白相作用的RNA等非编码RNA,对蜜蜂、蚂蚁及白蚁等真社会性昆虫的非编码RNA调控机制研究进展进行了综述,以加深对真社会性昆虫内在遗传分子基础的理解和认识,也为害虫防治领域提供新的研发视角。     

表皮碳氢化合物在社会性昆虫中的功能多样性及其调控

表皮碳氢化合物(cuticular hydrocarbons, CHCs)是一类广泛分布于昆虫表皮的烃类混合物,具有防水、抵抗有害物质入侵和化学通讯等功能,为昆虫适应陆地的多种生活方式作出巨大贡献。相较于独(寡)居昆虫,社会性昆虫CHCs的组成和功能多样性将有益于探究社会性昆虫所特有的遗传结构、群体组成和行为模式。因此,本文对社会性昆虫CHCs的结构、性质及功能进行了总结,并对影响其组成多样化的内源和外源因子进行了讨论,同时对未来的研究方向进行了展望。社会性昆虫的CHCs能介导同巢个体识别、级型分化、社会分工、群体免疫、生殖状态识别及种间互作,甚至部分CHCs已经进化为功能高度专一的蜂王(蚁后)信息素。社会性昆虫可能需要较高的CHCs组分多样性以适应其功能分化,而多种内源(基因和激素水平)及外源因素(食物、肠道微生物、病原生物、温湿度、紫外辐射及巢穴材料等)均能影响CHCs的组成。未来,借助定量遗传框架、免疫组化定位、荧光原位杂交等多种新兴技术,对社会性昆虫及其他昆虫类群CHCs合成、转运、释放、功能多样性及其调控机制进行研究,将有助于深入理解CHCs对昆虫适应性进化的重要贡献,并为开发基于CHCs的重大入侵和农林害虫的防控新技术提供理论参考。     

社会性昆虫品级分化的基因调控

品级分化是社会性昆虫的主要特征之一,包括雌性分化为生殖个体和非生殖个体,这一分化过程是受基因调控的。目前对社会性昆虫品级分化相关基因表达研究的报道较多,但是对这一分化的调控机制并不十分清楚,对这些基因的来源还存在争议。文章对社会性昆虫品级分化相关基因的研究概况作一综述,以期对以后相关方面的深入研究有所帮助。     

Developmental aspects of kin recognition

The ability to recognise kin requires the individual to possess a variety of abilities. Individuals must produce a cue which indicates relatedness, they must process this cue to determine relatedness and then must act on this cue. Research has concentrated on the first and final stage of this process, i.e., the cues of kinship and kin correlated behaviour. Little attention has been paid to how individuals process cues to determine relatedness. This paper discusses how individuals ‘recognise’ kin, the exhibition of kin correlated behaviour and considers the role of the MHC in these processes. Two broad theories have emerged to explain how individuals recognise their kin: either a recognition gene(s) or some experiential mechanism. In mammals there is no evidence to suggest that recognition (the processing of the cue) is under genetic control but rather is the result of experience, learning about related individuals during development. Moreover studies on kin recognition in the domestic dog suggest that all kin are not recognised by the same process but different classes of kin, parents, siblings may well be recognised using different means. Studies of kin correlated behaviour suggest that the behaviour exhibited towards kin by Mongolian gerbils is mediated by the environment. Factors of environmental familiarity, sex and developmental age all affect the response of individuals to kin and non‐kin. In these situations the ability to recognise kin does not change but the exhibition of kin correlated behaviour changes according to environmental conditions. These studies indicate that kin recognition may not be the ‘unified’ process previously thought and thus any explanations of the proximate and ultimate causation of kin recognition need to encompass this complexity. The question remains of whether the MHC is complex enough to do so. This revised version was published online in July 2006 with corrections to the Cover Date.     

How effective is recognition of siblings on the basis of genotype?

The ability to recognize kin based on genetic markers has been widely proposed as a mechanism to facilitate altruistic behaviour and inbreeding avoidance. Siblings are an important group of relatives to discriminate from unrelated individuals but present a problem, because siblings can share 0, 1 or 2 alleles at any single recognition locus. Here, we present a Bayesian model of kin recognition that defines the potential for genotypic information to convey kinship. Under the direct comparison model, where the signaller’s genotype is compared with that of the receiver, the odds ratio that a pair of individuals were siblings was substantially increased if they shared both alleles at a single locus, but only a minority of siblings were recognized; increasing the number of recognition loci used could not increase both the odds ratio and the proportion of siblings recognized. A maternal comparison model, where the signaller’s genotype is compared with that of the receiver’s mother, performed poorly when only a single recognition locus was considered, but became increasingly effective with more recognition loci. Nevertheless, incorporating partial‐matching information across multiple, independent loci are likely to be difficult. Further empirical work needs to establish the mechanistic basis of genetic kin recognition used by different taxa.     

Blending of heritable recognition cues among ant nestmates creates distinct colony gestalt odours but prevents within‐colony nepotism

The evolution of sociality is facilitated by the recognition of close kin, but if kin recognition is too accurate, nepotistic behaviour within societies can dissolve social cohesion. In social insects, cuticular hydrocarbons act as nestmate recognition cues and are usually mixed among colony members to create a Gestalt odour. Although earlier studies have established that hydrocarbon profiles are influenced by heritable factors, transfer among nestmates and additional environmental factors, no studies have quantified these relative contributions for separate compounds. Here, we use the ant Formica rufibarbis in a cross‐fostering design to test the degree to which hydrocarbons are heritably synthesized by young workers and transferred by their foster workers. Bioassays show that nestmate recognition has a significant heritable component. Multivariate quantitative analyses based on 38 hydrocarbons reveal that a subset of branched alkanes are heritably synthesized, but that these are also extensively transferred among nestmates. In contrast, especially linear alkanes are less heritable and little transferred; these are therefore unlikely to act as cues that allow within‐colony nepotistic discrimination or as nestmate recognition cues. These results indicate that heritable compounds are suitable for establishing a genetic Gestalt for efficient nestmate recognition, but that recognition cues within colonies are insufficiently distinct to allow nepotistic kin discrimination.     

Kinship Influences Cannibalism in the Wolf Spider, Pardosa milvina

Recent studies have called into question the role of Wright's coefficient of relatedness (r) in the interactions among relatives. Kin selection theory predicts a positive relationship between relatedness and frequency of altruistic acts, but a number of researchers have reported the opposite relationship. I used a lycosid spider (Pardosa milvina) to test the hypothesis that genetic relatedness would affect the propensity of a cannibalistic species to prey on genetic relatives. I considered lack of predation to be a form of altruism where the predator incurs a cost (loss of a meal) that benefits potential prey. Specifically, I questioned whether direct genetic offspring would be avoided as prey items and whether the sex or reproductive condition of a cannibalistic predator would affect the likelihood of predation on conspecific juveniles. As predicted by kin selection theory, spiderling mothers ate significantly fewer of their own offspring than they did of nonkin spiderlings of the same age. Adult virgin female and adult male spiders ate significantly more spiders than females that had recently carried spiderlings. Females with egg sacs consumed significantly fewer spiderlings than did virgin female spiders. These findings support Hamilton's rule and suggest that, in some systems, genetic relatedness plays a strong role in governing altruistic behavior toward relatives.