蝶类的拟态现象

拟态是一物种在形态、色型和行为上模拟另一物种,从而获得好处的行为,拟态可区分为贝次拟态、缪勒拟态和拟态集团3种类型。以蝶类为例介绍了这3种拟态的概念和实例,并论述了拟态现象的进化过程。     

昆虫拟态的历史发展

昆虫的拟态理论是由英国自然学家Bates于1862年提出的,Fisher称其为"达尔文后自然选择最重要的依据之一".大量的科学研究表明,昆虫的拟态行为最晚出现在石炭纪,自那时起昆虫与捕食者、昆虫与植物之间开始出现了共同的演变和进化.拟态的模仿方式一般包括颜色、花纹以及形态,但是也可以单指行为方面,且拟态大部分情况下可能模仿的是一个动物群体或者只是另外一种动物身上的一部分.拟态包括多种定义,不同的定义之间用小同的标准来区分拟态现象和非拟态现象,如贝茨氏拟态、缪勒氏拟态、侵略性拟态和瓦曼氏拟态等.本文从其中广义拟态的角度,对当前不同类群昆虫化石中拟态现象的研究进展进行了简要总结.     

探析植物欺骗性传粉中的生物拟态现象

植物欺骗性传粉中的生物拟态，目前尚未被完全认识。本文从拟态的特点出发，主要探讨了欺骗性传粉中不同欺骗类型和拟态之间的对应关系，分析得出欺骗性传粉并不都是拟态。非拟态、不完全的拟态与相对完全的拟态三者之间存在相互演化关系。举例论述欺骗性传粉中拟态的生态学意义，揭示拟态研究对于理解物种演化和生物多样性保护的重要意义。     

天目山蛾类拟态初探

天目山蛾类种类繁多,数量丰富,其拟态现象更是千姿百态,文中介绍了天目山的几种蛾类的拟态,并对蛾类不同生长阶段的拟态现象,蛾类拟态对人类活动的适应以及拟态的行为学机制等问题进行了初步探讨。     

中国拟态蛛属一新种记述：蜘蛛目：拟态蛛科

本文记述采自湖北的拟态蛛科拟态蛛属一新种,定名为中华拟态蛛Ｍｉｍｅｔｕｓ ｓｉｎｉｃｕｓ ｓｐ．ｎｏｖ．     

中草药复方对拟态弧菌的体内外抗菌和拮抗外毒素的作用

目的探明拟态弧菌外毒素的致病性,筛选出对拟态弧菌具有良好抗菌和拮抗外毒素作用的中草药复方。方法培养拟态弧菌安徽分离株,采用蛋白分离技术提取其外毒素,测定其对实验草鱼的致病性。以黄连、大黄、金银花、夏枯草、丹皮、地锦草、连翘、茯苓、车前子、黄芪和甘草组成3个复方,采用改良微量稀释法测定不同中草药复方对拟态弧菌的体外抑菌作用。同时使用动物模型测定不同中草药复方拮抗外毒素作用和对拟态弧菌感染草鱼的保护作用。结果4株拟态弧菌产生的外毒素对实验鱼均具有较强的致死性。复方3的体外抑菌作用最强,对4株拟态弧菌的MIC值均为1.96g/L;其次为复方1,其MIC值介于3.92～7.84g/L;复方2的抑菌作用最差,其MIC值介于62.72～125g/L。复方3拮抗外毒素作用最强,其次为复方2,复方1不具有抗毒素作用。复方3对拟态弧菌感染草鱼具有最好的保护作用,保护率为100%;其次为复方2,保护率为23.81%;复方1的保护率最低,仅为19.05%。结论拟态弧菌外毒素在腹水病发生过程中起着重要致病作用。复方3具有良好的抗菌和拮抗外毒素作用,为筛选出的最佳复方,可进一步研制成为治疗腹水病的中草药复方制剂。     

研究选萃

<正>蝴蝶拟态功能由超级基因簇决定自然界中,不少蝴蝶掌握借助"拟态"躲避天敌的本领。一项最新研究发现,蝴蝶的拟态功能由其体内的"超级基因簇"决定。英法两国研究人员在2011年8月的《自然》杂志上发表论文说,他们选取了一种生长在亚马逊热带雨林地区的     

全反式维甲酸对U87-MG细胞裸鼠皮下移植瘤模型中血管生成拟态的影响

目的:明确全反式维甲酸对人恶性脑胶质瘤U87-MG细胞体内血管拟态形成的影响。方法:体外培养U87-MG细胞,并建立裸鼠皮下移植瘤模型,利用全反式维甲酸进行干预,检测荷瘤裸鼠肿瘤生长情况;利用HE染色对肿瘤组织进行细胞形态学观察;利用CD34-PAS双染法观察肿瘤血管拟态的形成情况。结果:U87-MG细胞在裸鼠体内成功荷瘤并出现血管拟态;全反式维甲酸显著抑制了U87-MG细胞实体瘤的生长和血管拟态的形成。结论:全反式维甲酸具有显著的抗肿瘤能力,其作用机制与血管拟态形成相关。     

江苏水产养殖区拟态弧菌种群结构及遗传多样性

【背景】拟态弧菌(Vibrio mimicus)是一种常见的革兰氏阴性病原菌,广泛分布于水环境和水生动物体内,可导致多种水产动物和人类感染。多位点序列分型(multilocus sequence typing, MLST)已被应用于多种病原菌的分子分型,其通过分析不同菌株之间的遗传关系,监测细菌传播的时间和地理分布,确定感染和传播途径,但目前未见有关拟态弧菌MLST的报道。【目的】开发一种基于MLST的拟态弧菌分型方法,并用于江苏水产养殖区拟态弧菌的种群结构和遗传进化分析,为拟态弧菌感染所引起的疾病防治提供理论基础。【方法】选择拟态弧菌的7个管家基因dnaE、gyrB、mdh、recA、rpoD、pntA和pyrH作为靶点,对江苏水产养殖区分离的155株拟态弧菌进行PCR扩增和测序。将测序结果分配等位基因,制作等位基因谱,分配不同的序列类型(sequence type, ST),利用软件goeBURST-1.2.1和MEGA-X对分配的ST型进行克隆复合体和遗传进化树聚类分析;此外,利用Kirby-Bauer圆盘扩散法测试155株拟态弧菌的药敏特性。【结果】155株拟态弧菌被分为56个STs,其中ST11占比最高;在双位点变异(double locus variants, DLV)水平分析发现56个STs分为3个克隆复合体和3个单体;系统发育树显示,56个STs被分为3个集群(cluster I、cluster II、cluster III)。药敏结果显示,155株拟态弧菌对红霉素类抗生素的耐药性最高(88.39%, 137/155),对氯霉素类抗生素敏感性最高(91.61%, 142/155)。【结论】本研究建立的MLST方法具有良好的分辨率,可作为拟态弧菌系统发育和未来流行病学调查有用的分子分型工具。根据抗生素耐药谱结果,提示在养殖过程中可选用氟苯尼考等国家批准使用的专用抗菌药对拟态弧菌进行防治。     

中生代丽蛉拟态及灭绝机制的探讨(脉翅目,丽蛉科)

对新近发现于内蒙古和辽宁的多块脉翅目丽蛉科化石上的眼斑进行了描述,根据现生昆虫的拟态及现存脉翅目昆虫的行为特点,分析了丽蛉在进化上出现的拟态现象在当时的古生态环境中可能起到恐吓捕食者和引诱猎物的作用。眼斑拟态这种高度特化的生态适应现象使得多脉丽褐蛉在当时的古生态群落中占据了十分独特的生态位,同时也导致了其在中生代晚期环境突然变化中的灭绝。     

Molecular mechanisms of floral mimicry in orchids

Deceptive plants do not produce floral rewards, but attract pollinators by mimicking signals of other organisms, such as food plants or female insects. Such floral mimicry is particularly common in orchids, in which flower morphology, coloration and odour play key roles in deceiving pollinators. A better understanding of the molecular bases for these traits should provide new insights into the occurrence, mechanisms and evolutionary consequences of floral mimicry. It should also reveal the molecular bases of pollinator-attracting signals, in addition to providing strategies for manipulating insect behaviour in general. Here, we review data on the molecular bases for traits involved in floral mimicry, and we describe methodological advances helpful for the functional evaluation of key genes.     

Batesian insect-insect mimicry-related explosive radiation of ancient alienopterid cockroaches

Batesian mimicry is a relationship in which a harmful organism (the model) is mimicked by a harmless organism (the mimic), which gains protection because predators mistake it for the model. It is the most widely studied of mimicry complexes and has undoubtedly played an important role in the speciation of various animals especially insects. However, little is known about the early evolution of this important behavior and its evolutionary significance owing to a dearth of paleontological records. Here we report several specialized representatives of the family Alienopteridae from the Early Cretaceous of Brazil, mid-Cretaceous Burmite, and the Eocene of the USA. They exhibit unique morphological adaptations for wasp and ant mimicry and represent one of the oldest evidence of Batesian mimicry in the insect fossil record. Our findings reveal at least 65-million-year coevolution between extinct alienopterids and aculeates. Phylogenetic Bayesian network analysis houses Alienopteridae within Umenocoleidae explosively radiating ~127 Ma. Alienopteridae is the only Mesozoic-type cockroach family which passed K/Pg.     

Causes and Consequences of a Lack of Coevolution in Müllerian mimicry

Müllerian mimicry, in which both partners are unpalatable to predators, is often used as an example of a coevolved mutualism. However, it is theoretically possible that some Müllerian mimics are parasitic if a weakly defended mimic benefits at the expense of a more highly defended model, a phenomenon known as ‘quasi-Batesian mimicry’. The theory expounded by Müller and extended here for unequal unpalatability, on the other hand, suggests that quasi-Batesian mimicry should be rare in comparison with classical, or mutualistic Müllerian mimicry. Evolutionarily, quasi-Batesian mimicry has consequences similar to classical Batesian mimicry, including unilateral ‘advergence’ of the mimic to the model, and diversifying frequency-dependent selection on the mimic which may lead to mimetic polymorphism. In this paper, theory and empirical evidence for mutual benefit and coevolution in Müllerian mimicry are reviewed. I use examples from well-known insect Müllerian mimicry complexes: the Limenitis–Danaus (Nymphalidae) system in North America, the Bombus–Psithyrus (Apidae) system in the north temperate zone, and the Heliconius–Laparus (Nymphalidae) system in tropical America. These give abundant evidence for unilateral advergence, and no convincing evidence, to my knowledge, for coevolved mutual convergence. Furthermore, mimetic polymorphisms are not uncommon. Yet classical mutualistic Müllerian mimicry, coupled with spatial (and possibly temporal) variation in model abundances convincingly explain these apparent anomalies without recourse to a quasi-Batesian explanation. Nevertheless, the case against classical Müllerian mimicry is not totally disproved, and should be investigated further. I hope that this tentative analysis of actual mimicry rings may encourage others to look for evidence of coevolution and quasi-Batesian effects in a variety of other Müllerian mimicry systems. This revised version was published online in July 2006 with corrections to the Cover Date.     

Robot predators in virtual ecologies: the importance of memory in mimicry studies

An important means of investigating gains and losses to prey caused by mimicry is through mathematical or computer constructs which represent and explore limited aspects of mimicry situations. Such studies use virtual predators which are usually simple automata, 'robots' that, through simple rules, vary virtual attack rates on virtual insect prey. In this paper I consider the effect of variations in predator memory and learning on mimicry dynamics. When there is mimicry between unequally noxious prey, the way that memory is modelled is shown to be crucial. If forgetting rates are fixed, an increase in the density of the least defended prey produces monotonic gains or losses in protection. However, if forgetting rate is inversely related in some way to degree of noxiousness of the prey then attack rates initially rise with the density of the least defended prey, reach a cusp and then fall. I show that the generation of this highly unconventional up-down result appears to be independent of variations in learning rate. This work shows how sensitive the predictions of virtual predators may be to relatively small changes in behavioural rules. Copyright 1999 The Association for the Study of Animal Behaviour.     

Intrasexual mounting in the beetle Diaprepes abbreviatus (L.).

The weevil Diaprepes abbreviatus shows three kinds of same-sex mountings: males mount other unpaired males, males mount males already engaged in copulation and females mount other females. Four hypotheses were evaluated in order to explain same-sex matings by males: (i) female mimicry by inferior males, (ii) dominance of larger males which affects the behaviour of small males, (iii) sperm transfer in which smaller males gain some reproductive success by 'hitchhiking' their sperm with the sperm of larger males, and (iv) poor sex recognition. Data from mate choice and sperm competition experiments rejected the female mimicry, dominance and sperm transfer hypotheses and supported the poor sex recognition hypothesis. We tested three hypotheses in order to explain female mounting behaviour: (i) females mimic male behaviour in order to reduce sexual harassment by males, (ii) females mount other females in order to appear larger and thereby attract more and larger males for mating, and (iii) female mimicry of males. The results of our mate choice experiments suggested that the female mimicry of males hypothesis best explains the observed female mounting behaviour. This result is also consistent with the poor sex recognition hypothesis which is the most likely explanation for male and female intrasexual mating behaviour in many insect species.     

Versatile Aggressive Mimicry of Cicadas by an Australian Predatory Katydid

Background

In aggressive mimicry, a predator or parasite imitates a signal of another species in order to exploit the recipient of the signal. Some of the most remarkable examples of aggressive mimicry involve exploitation of a complex signal-response system by an unrelated predator species.

Methodology/Principal Findings

We have found that predatory Chlorobalius leucoviridis katydids (Orthoptera: Tettigoniidae) can attract male cicadas (Hemiptera: Cicadidae) by imitating the species-specific wing-flick replies of sexually receptive female cicadas. This aggressive mimicry is accomplished both acoustically, with tegminal clicks, and visually, with synchronized body jerks. Remarkably, the katydids respond effectively to a variety of complex, species-specific Cicadettini songs, including songs of many cicada species that the predator has never encountered.

Conclusions/Significance

We propose that the versatility of aggressive mimicry in C. leucoviridis is accomplished by exploiting general design elements common to the songs of many acoustically signaling insects that use duets in pair-formation. Consideration of the mechanism of versatile mimicry in C. leucoviridis may illuminate processes driving the evolution of insect acoustic signals, which play a central role in reproductive isolation of populations and the formation of species.     

Lepidopteran wing patterns and the evolution of satyric mimicry

The hypothesis of satyric mimicry postulates that the colour patterns of an animal may make its identity ambiguous, and this ambiguity interferes with the process of perception in vertebrate predators for a sufficient time to allow the potential prey to take evasive action. It has now been found that eyespots and other designs on the wings of many insect species are often coupled with other wing patterns and designs. These composite images often closely resemble heads and bodies of vertebrates (including birds and reptiles) and of various invertebrates. Such images can be perceived in living insects, although only rarely in set specimens because of displacement of the components. Visual processing by non‐mammalian vertebrates generally involves attention to detail, suggesting that, at least initially, and unlike humans, they perceive embedded images on insect wings and bodies and ignore the whole or Gestalt. They are therefore likely to be confused by the ambiguity of the potential prey. It can be calculated that a delay of the order of only tenths of a second in the attack on a stationary insect by a predator could result in failure of capture. It is proposed in the present review that the concept of satyric mimicry be extended to include complex imagery of other organisms. Such iconic images, which often represent toxic or dangerous animals, are particularly common amongst saturniid moths and nymphalid and danaid butterflies (including the Monarch butterfly, Danaus plexippus). © 2013 The Linnean Society of London, Biological Journal of the Linnean Society, 2013, 109 , 203–214.     

Parallel evolution of termite‐egg mimicry by sclerotium‐forming fungi in distant termite groups

Among the great diversity of insect–fungus associations, fungal mimicry of termite eggs is a particularly fascinating consequence of evolution. Along with their eggs, Reticulitermes termites often harbour sclerotia of the fungus Fibularhizoctonia sp., called ‘termite balls’, giving the fungus competitor‐free habitat within termite nests. The fungus has evolved sophisticated morphological and chemical camouflage to mimic termite eggs. To date, this striking insect–fungus association has been found in eight temperate termite species, but is restricted to the lower termite genera Reticulitermes and Coptotermes. Here, we report the discovery of a novel type of termite ball (‘Z‐type’) in the subtropical termite, Nasutitermes takasagoensis. Phylogenetic analysis indicated that the Z‐type termite ball is an undescribed Trechisporoid fungus, Trechispora sp., that is phylogenetically distant from Fibularhizoctonia, indicating two independent origins of termite‐egg mimicry in sclerotium‐forming fungi. Egg protection bioassays using dummy eggs revealed that Reticulitermes speratus and N. takasagoensis differ in egg‐size preference. A comparative study of termite ball size and egg‐size preference of host termites showed that both fungi evolved a termite ball size that optimized the acceptance of termite balls as a unit investment. Termite‐egg mimicry by these fungi offers a model case of parallel evolution. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 100 , 531–537.     

Unlinked Mendelian inheritance of red and black pigmentation in snakes: Implications for Batesian mimicry

Identifying the genetic basis of mimetic signals is critical to understanding both the origin and dynamics of mimicry over time. For species not amenable to large laboratory breeding studies, widespread color polymorphism across natural populations offers a powerful way to assess the relative likelihood of different genetic systems given observed phenotypic frequencies. We classified color phenotype for 2175 ground snakes (Sonora semiannulata) across the continental United States to analyze morph ratios and test among competing hypotheses about the genetic architecture underlying red and black coloration in coral snake mimics. We found strong support for a two‐locus model under simple Mendelian inheritance, with red and black pigmentation being controlled by separate loci. We found no evidence of either linkage disequilibrium between loci or sex linkage. In contrast to Batesian mimicry systems such as butterflies in which all color signal components are linked into a single “supergene,” our results suggest that the mimetic signal in colubrid snakes can be disrupted through simple recombination and that color evolution is likely to involve discrete gains and losses of each signal component. Both outcomes are likely to contribute to the exponential increase in rates of color evolution seen in snake mimicry systems over insect systems.