兰科植物欺骗性传粉

植物与传粉动物的互利关系在生态系统中非常普遍。然而,有许多植物不为传粉者提供任何报酬,而是利用各种欺骗方式诱骗昆虫拜访,从而实现传粉,即欺骗性传粉。兰科是被子植物大科之一,其高度特化的繁殖器官和适应于昆虫传粉的精巧结构令人称奇。进化论创始人达尔文描述了许多兰花与昆虫精巧的传粉系统,但他忽视了欺骗性传粉的存在。事实上,近1/3的兰科植物都依赖于欺骗性传粉。欺骗性传粉可能是导致兰科植物多样性的重要原因之一。兰花利用或操作昆虫觅食、交配、产卵和栖息等行为,演化出各种各样的欺骗性传粉机制,常见的类型包括泛化的食源性欺骗、Batesian拟态、性欺骗、产卵地拟态和栖息地拟态。花的颜色、形态和气味在欺骗性传粉的成功实现中起到了重要作用。欺骗性兰花与传粉昆虫之间的演化可能是不同步的,兰花追踪昆虫的行为信号而发生分化,然而欺骗性传粉可能对昆虫造成一定的伤害,从而对昆虫也施加选择压力。由于昆虫的学习行为,欺骗性的兰花一般具有低的昆虫拜访率和结实率,其繁殖成功率受各种因素的影响。欺骗性加剧了兰花对传粉昆虫的依赖,使其具有更高的灭绝风险,传粉生物学的研究能为兰科植物的有效保护提供指导。在欺骗性传粉系统中,有报酬的伴生植物、拟态模型和其他拟态信号提供者对传粉成功有重要影响。因此,研究欺骗性传粉兰花、传粉昆虫和相关的生物和生态因子的网状进化关系具有重要理论和实践意义。     

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。     

昆虫拟态的多样性

综述了昆虫拟态的常见类型及其研究动态 ,特别对光学拟态、声学拟态、化学拟态和拟态的多型现象及复杂性作了较详细的介绍     

生物拟态

生物拟态朱晓林（山东泰安第二中学２７１０００）拟态（ｍｉｍｉｃｒｙ）是指某些生物在进化过程中形成的外表形状或色泽斑与其它生物或非生物异常相似的现象,是生物适应环境的最为典型的例子。随着生态学研究的不断深入,人们发现动物甚至植物拟态的现象是十分普遍的,...     

Ancient pinnate leaf mimesis in Mesozoic lacewings

拟态是一种生物模拟另一种生物或环境中的其它物体从而使自身获得好处的现象,是昆虫在进化过程中特化出的一种极为重要和有效的防御策略.脉翅目昆虫是一类完全变态性昆虫,在其超过2.7亿年的演化历史中,出现了形态多样的翅斑.美翼蛉属Bellinympha Wang,Ren,Liu,Shih&Engel,2010是脉翅目溪蛉科丽翼蛉亚科的一个绝灭属,发现于中国内蒙古道虎沟地区中侏罗世九龙山组地层.该属的发现代表了迄今报道的最古老的叶状拟态现象,也是唯一报道的昆虫模拟裸子植物或蕨类植物叶片.本文简要概述了脉翅目昆虫研究概况,总结了中生代脉翅目翅斑的多样性,对美翼蛉属进行了描述,并对其叶状拟态及其生物学意义进行了探讨.     

中生代脉翅目昆虫的叶状拟态

拟态是一种生物模拟另一种生物或环境中的其它物体从而使自身获得好处的现象,是昆虫在进化过程中特化出的一种极为重要和有效的防御策略。脉翅目昆虫是一类完全变态性昆虫,在其超过2.7亿年的演化历史中,出现了形态多样的翅斑。美翼蛉属Bellinympha Wang,Ren,Liu,Shih&Engel,2010是脉翅目溪蛉科丽翼蛉亚科的一个绝灭属,发现于中国内蒙古道虎沟地区中侏罗世九龙山组地层。该属的发现代表了迄今报道的最古老的叶状拟态现象,也是唯一报道的昆虫模拟裸子植物或蕨类植物叶片。本文简要概述了脉翅目昆虫研究概况,总结了中生代脉翅目翅斑的多样性,对美翼蛉属进行了描述,并对其叶状拟态及其生物学意义进行了探讨。     

和虫虫玩儿捉迷藏（上）

拟态就是动物模拟其他生物姿态或者周围环境以保护自己的能力,是生物长期进化的结果。在拍摄拟态昆虫的过程中一定要小心翼翼,如果它们受到惊吓飞走,或者掉在地上的枯枝堆中,也许你就再也找不到你的"模特"了……     

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。     

拟态拟势拟死

拟态拟势拟死朱晓林山东泰安二中,２７１０００拟态（ｍｉｍｉｃｒ）是指某些生物进化过程中形成的外表形状或色泽斑与其它生物或非生物异常相似的的现象,是生物适应环境的典型例子。动物拟态的实例,除大家较熟悉的竹节虫、枯叶蝶等．还可举出很多,如海神弄蝶的卵看上...     

植物生殖过程中的寄生和拟态

介绍了寄生现象和拟态现象在植物生殖过程中的作用.     

Playing with Black and Yellow: The Evolvability of a Batesian Mimicry

Irrespective of the selective advantage deriving from similar color pattern, the evolution of Batesian (and Müllerian) mimicry between distantly related insects groups has been perhaps facilitated by the availability to both models and mimics of similar pattern units more likely to be expressed, and to be modified in parallel ways, due to shared developmental constraints. We explore this hypothesis in a comparison of units of black-and-yellow color patterns between wasps (Vespidae) and those syrphids (Syrphidae) that are considered to be their Batesian mimics. As a proxy for evolvability we analyzed the co-occurrence of multiple color pattern within species (either as serial homologues or as expression of intraspecific variation) in 203 species of syrphids and 127 species of wasps. In both the wasps and the syrphids, the most frequent black-and-yellow patterns on the abdomen—all shared between the two insect groups—are also the most extensively linked in the networks of intraspecific co-occurrence, but are not the same in the two insect groups: in accordance with our hypothesis, this suggests positively biased evolvability.     

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.     

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.     

Avian vision and the evolution of egg color mimicry in the common cuckoo

Coevolutionary arms races are a potent force in evolution, and brood parasite-host dynamics provide classical examples. Different host-races of the common cuckoo, Cuculus canorus, lay eggs in the nests of other species, leaving all parental care to hosts. Cuckoo eggs often (but not always) appear to match remarkably the color and pattern of host eggs, thus reducing detection by hosts. However, most studies of egg mimicry focus on human assessments or reflectance spectra, which fail to account for avian vision. Here, we use discrimination and tetrachromatic color space modeling of bird vision to quantify egg background and spot color mimicry in the common cuckoo and 11 of its principal hosts, and we relate this to egg rejection by different hosts. Egg background color and luminance are strongly mimicked by most cuckoo host-races, and mimicry is better when hosts show strong rejection. We introduce a novel measure of color mimicry-"color overlap"-and show that cuckoo and host background colors increasingly overlap in avian color space as hosts exhibit stronger rejection. Finally, cuckoos with better background color mimicry also have better pattern mimicry. Our findings reveal new information about egg mimicry that would be impossible to derive by the human eye.     

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.     

Smells like aphids: orchid flowers mimic aphid alarm pheromones to attract hoverflies for pollination

Most insects are dependent on chemical communication for activities such as mate finding or host location. Several plants, and especially orchids, mimic insect semiochemicals to attract insects for unrewarded pollination. Here, we present a new case of pheromone mimicry found in the terrestrial orchid Epipactis veratrifolia. Flowers are visited and pollinated by several species of aphidophagous hoverflies, the females of which also often lay eggs in the flowers. The oviposition behaviour of these hoverflies is mainly guided by aphid-derived kairomones. We show that the flowers produce α- and β-pinene, β-myrcene and β-phellandrene, and that these compounds attract and induce oviposition behaviour in female hoverflies. This floral odour profile is remarkably similar to the alarm pheromone released by several aphid species, such as Megoura viciae. We therefore suggest that E. veratrifolia mimics aphid alarm pheromones to attract hoverflies for pollination; this is the first time, to our knowledge, that such a case of mimicry has been demonstrated.     

Chemical mimicry of insect oviposition sites: a global analysis of convergence in angiosperms

Floral mimicry of decaying plant or animal material has evolved in many plant lineages and exploits, for the purpose of pollination, insects seeking oviposition sites. Existing studies suggest that volatile signals play a particularly important role in these mimicry systems. Here, we present the first large‐scale phylogenetically informed study of patterns of evolution in the volatile emissions of plants that mimic insect oviposition sites. Multivariate analyses showed strong convergent evolution, represented by distinct clusters in chemical phenotype space of plants that mimic animal carrion, decaying plant material, herbivore dung and omnivore/carnivore faeces respectively. These plants deploy universal infochemicals that serve as indicators for the main nutrients utilised by saprophagous, coprophagous and necrophagous insects. The emission of oligosulphide‐dominated volatile blends very similar to those emitted by carrion has evolved independently in at least five plant families (Annonaceae, Apocynaceae, Araceae, Orchidaceae and Rafflesiaceae) and characterises plants associated mainly with pollination by necrophagous flies and beetles.     

NEGATIVE FREQUENCY-DEPENDENT SELECTION BY POLLINATORS ON ARTIFICIAL FLOWERS WITHOUT REWARDS

Many species of nonmodel deceptively pollinated orchids are polymorphic for corolla color. These species are pollinated by naive insects searching for nectar, and are not mimics. It has been suggested that the foraging behavior of insect pollinators during the avoidance learning process results in these stable corolla color polymorphisms; for this to occur pollinators must induce negative frequency-dependent selection on corolla color. Therefore the hypothesis that pollinator behavior results in a preference for rare color morphs of deceptive species was tested experimentally. Bumblebees (Bombus terrestris) foraged in the laboratory on arrays of artificial flowers with different corolla color morphs. Morphs were varied in frequency, and bumblebee preferences were recorded on arrays where morphs did and did not contain sucrose solution rewards. Bumblebees preferred the most common color morph when flowers contained sucrose solution rewards, but overvisited rare morphs when sampling flowers that contained no rewards. Bumblebees also tended to move between unlike color morphs when these were unrewarding, suggesting that a probabilistic sampling strategy was adopted. Thus experiments demonstrated that pollinator behavior could result in a selective advantage for rare color morphs of plant species that are pollinated by deception without mimicry, which would induce negative frequency-dependent selection on corolla color. The observed pollinator behavior could allow stable corolla color polymorphisms to be maintained by selection in nonmodel deceptively pollinated species.     

昆虫体色多型的分子调控机制

体色多型普遍存在于各昆虫类群,体色多型不仅是生物多样性的体现,而且多样的着色模式对于昆虫本身具有重要的生物学意义.研究体色多型对探讨昆虫遗传多态性、适应机制及生物进化等具有重要的意义.本文主要从昆虫体色多型的分子调控机制进行综述,以期为今后探讨昆虫多态性、适应机制及生物进化提供参考.     

On the elusiveness of enemy-free space: spatial, temporal, and host-plant-related variation in parasitoid attack rates on three gallmakers of goldenrods

Host shifting by phytophagous insects may play an important role in generating insect diversity by initiating host-race formation and speciation. Models of the host shifting process often invoke reduced rates of natural enemy attack on a novel host in order to balance the maladaptation expected following the shift. Such "enemy-free space" has been documented for some insects, at some times and places, but few studies have assessed the occurrence of enemy-free space across years, among sites, or among insect species. We measured parasitoid attack rates on three insect herbivores of two goldenrods (Solidago altissima L. and Solidago gigantea Ait.), with data from multiple sites and multiple years for each herbivore. For each insect herbivore, there were times and sites at which parasitoid attack rates differed strongly and significantly between host plants (that is, enemy-free space existed on one host plant or the other). However, the extent and even the direction of the attack-rate difference varied strongly among sites and even among years at the same site. There was no evidence of consistent enemy-free space for any herbivore on either host plant. Our data suggest that enemy-free space, like many ecological and evolutionary forces, is likely to operate as a geographic and temporal mosaic, and that conceptual models of host shifting that include enemy-free space as a consequence of host novelty are likely too simple.