性选择与性冲突理论在植物繁殖生态学中的应用与进展

性选择与性冲突是植物繁殖性状多样性及性系统演化的重要动力, 二者密切相关却又有所区别, 理解它们的作用机制及其影响对于植物繁殖生态学的研究具有重要意义。当前, 性选择与性冲突理论在植物繁殖生态学中的运用已取得长足进展, 但国内相关研究较少, 对该领域关注不够。因此, 该文对该领域的基本理论和研究进展进行了综述。首先, 阐述性选择与性冲突理论在植物研究中的发展及其运用基础; 其次, 分别从授粉前和授粉后两个阶段详细介绍性选择与性冲突在有花植物繁殖过程中的作用机制及其影响, 并指出环境因素对它们所产生的影响; 最后, 对当前研究存在的不足及该领域未来的研究方向进行总结和展望。希望以此增强人们对性选择和性冲突理论的认识, 促进其在植物繁殖生态学中的运用与发展。     

The evolutionary ecology of the Lygaeidae

The Lygaeidae (sensu lato) are a highly successful family of true bugs found worldwide, yet many aspects of their ecology and evolution remain obscure or unknown. While a few species have attracted considerable attention as model species for the study of insect physiology, it is only relatively recently that biologists have begun to explore aspects of their behavior, life history evolution, and patterns of intra‐ and interspecific ecological interactions across more species. As a result though, a range of new phenotypes and opportunities for addressing current questions in evolutionary ecology has been uncovered. For example, researchers have revealed hitherto unexpectedly rich patterns of bacterial symbiosis, begun to explore the evolutionary function of the family's complex genitalia, and also found evidence of parthenogenesis. Here we review our current understanding of the biology and ecology of the group as a whole, focusing on several of the best‐studied characteristics of the group, including aposematism (i.e., the evolution of warning coloration), chemical communication, sexual selection (especially, postcopulatory sexual selection), sexual conflict, and patterns of host‐endosymbiont coevolution. Importantly, many of these aspects of lygaeid biology are likely to interact, offering new avenues for research, for instance into how the evolution of aposematism influences sexual selection. With the growing availability of genomic tools for previously “non‐model” organisms, combined with the relative ease of keeping many of the polyphagous species in the laboratory, we argue that these bugs offer many opportunities for behavioral and evolutionary ecologists.     

Pre-adaptations and the evolution of pollination by sexual deception: Cope's rule of specialization revisited

Pollination by sexual deception is arguably one of the most unusual liaisons linking plants and insects, and perhaps the most illustrative example of extreme floral specialization in angiosperms. While considerable progress has been made in understanding the floral traits involved in sexual deception, less is known about how this remarkable mimicry system might have arisen, the role of pre-adaptations in promoting its evolution and its extent as a pollination mechanism outside the few groups of plants (primarily orchids) where it has been described to date. In the Euro-Mediterranean region, pollination by sexual deception is traditionally considered to be the hallmark of the orchid genus Ophrys. Here, we introduce two new cases outside of Ophrys, in plant groups dominated by generalized, shelter-mimicking species. On the basis of phylogenetic reconstructions of ancestral pollination strategies, we provide evidence for independent and bidirectional evolutionary transitions between generalized (shelter mimicry) and specialized (sexual deception) pollination strategies in three groups of flowering plants, and suggest that pseudocopulation has evolved from pre-adaptations (floral colours, shapes and odour bouquets) that selectively attract male pollinators through shelter mimicry. These findings, along with comparative analyses of floral traits (colours and scents), shed light on particular phenotypic changes that might have fuelled the parallel evolution of these extraordinary pollination strategies. Collectively, our results provide the first substantive insights into how pollination sexual deception might have evolved in the Euro-Mediterranean region, and demonstrate that even the most extreme cases of pollinator specialization can reverse to more generalized interactions, breaking ‘Cope''s rule of specialization’.     

Sexy sons from re-mating do not recoup the direct costs of harmful male interactions in the Drosophila melanogaster laboratory model system

The empirical foundation for sexual conflict theory is the data from many different taxa demonstrating that females are harmed while interacting with males. However, the interpretation of this keystone evidence has been challenged because females may more than counterbalance the direct costs of interacting with males by the indirect benefits of obtaining higher quality genes for their offspring. A quantification of this trade-off is critical to resolve the controversy and is presented here. A multi-generation fitness assay in the Drosophila melanogaster laboratory model system was used to quantify both the direct costs to females due to interactions with males and indirect benefits via sexy sons. We specifically focus on the interactions that occur between males and nonvirgin females. In the laboratory environment of our base population, females mate soon after eclosion and store sufficient sperm for their entire lifetime, yet males persistently court these nonvirgin females and frequently succeed in re-mating them. Females may benefit from these interactions despite direct costs to their lifetime fecundity if re-mating allows them to trade-up to mates of higher genetic quality and thereby secure indirect benefits for their offspring. We found that direct costs of interactions between males and nonvirgin females substantially exceeded indirect benefits through sexy sons. These data, in combination with past studies of the good genes route of indirect benefits, demonstrate that inter-sexual interactions drive sexually antagonistic co-evolution in this model system.     

Weed macaques: The evolutionary implications of macaque feeding ecology

Patterns of feeding ecology among the living macaques conform poorly with recognized phyletic distinctions within the genus because there is an important ecological division which cross-cuts phyletic groupings. This division, between weed species and non-weed species, is based on the differing abilities of macaques to tolerate and even prosper in close association with human settlements. Based on available information about their ecology in the wild, we tentatively assign macaque species to these two categories. Finally, we consider the implications of our argument for scenarios of the initial spread of the macaques.     

British mammals: from trinomials to evolutionary ecology

The study of mammals in Britain has progressed from studies of distribution and differentiation to the present time, when new challenges face mammal workers. We need to build upon past achievements and use both new technology and old-fashioned dedicated observation to learn why what mammal is whew.     

The virtues and limitations of exploring the eco‐evolutionary dynamics of sexually selected traits

Most studies on eco‐evolutionary feedbacks concern the influence of abiotic factors, or predator–prey and host–parasite interactions, while studies involving sexual interactions are lagging behind. This is at odds with the potential of these interactions to engage in such processes. Indeed, there is now ample evidence that sexual selection is affected by ecological change and that sexually selected traits can evolve rapidly, which may modify the ecological context of populations, and thus the selection pressures they will be exposed to. Here we review evidence for such eco‐evolutionary processes. We discuss examples of eco‐evolutionary change in an attempt to understand the challenges related with identifying and characterizing such processes. In particular, we focus on the challenges associated with accurately identifying the components of the feedback as well as their causal relation. Finally, we evaluate scenarios where understanding eco‐evolutionary feedbacks of sexual selection may help us appreciate the effects of sexual selection in shaping evolutionary processes.     

Mixed company: a framework for understanding the composition and organization of mixed‐species animal groups

Mixed‐species animal groups (MSGs) are widely acknowledged to increase predator avoidance and foraging efficiency, among other benefits, and thereby increase participants' fitness. Diversity in MSG composition ranges from two to 70 species of very similar or completely different phenotypes. Yet consistency in organization is also observable in that one or a few species usually have disproportionate importance for MSG formation and/or maintenance. We propose a two‐dimensional framework for understanding this diversity and consistency, concentrating on the types of interactions possible between two individuals, usually of different species. One axis represents the similarity of benefit types traded between the individuals, while the second axis expresses asymmetry in the relative amount of benefits/costs accrued. Considering benefit types, one extreme represents the case of single‐species groups wherein all individuals obtain the same supplementary, group‐size‐related benefits, and the other extreme comprises associations of very different, but complementary species (e.g. one partner creates access to food while the other provides vigilance). The relevance of social information and the matching of activities (e.g. speed of movement) are highest for relationships on the supplementary side of this axis, but so is competition; relationships between species will occur at points along this gradient where the benefits outweigh the costs. Considering benefit amounts given or received, extreme asymmetry occurs when one species is exclusively a benefit provider and the other a benefit user. Within this parameter space, some MSG systems are constrained to one kind of interaction, such as shoals of fish of similar species or leader–follower interactions in fish and other taxa. Other MSGs, such as terrestrial bird flocks, can simultaneously include a variety of supplementary and complementary interactions. We review the benefits that species obtain across the diversity of MSG types, and argue that the degree and nature of asymmetry between benefit providers and users should be measured and not just assumed. We then discuss evolutionary shifts in MSG types, focusing on drivers towards similarity in group composition, and selection on benefit providers to enhance the benefits they can receive from other species. Finally, we conclude by considering how individual and collective behaviour in MSGs may influence both the structure and processes of communities.     

The evolutionary ecology of attachment organization

Life history theory’s principle of allocation suggests that because immature organisms cannot expend reproductive effort, the major trade-off facing juveniles will be the one between survival, on one hand, and growth and development, on the other. As a consequence, infants and children might be expected to possess psychobiological mechanisms for optimizing this trade-off. The main argument of this paper is that the attachment process serves this function and that individual differences in attachment organization (secure, insecure, and possibly others) may represent facultative adaptations to conditions of risk and uncertainty that were probably recurrent in the environment of human evolutionary adaptedness. An early version of this paper was presented in the symposium “Childhood in Life-history Perspective: Developing Views” organized by Gilda Morelli and Paula Ivey for the Annual Meeting of the Society for Cross-Cultural Research in Santa Fe, New Mexico, February 16–20, 1994. James S. Chisholm recently joined the Department of Anatomy and Human Biology at the University of Western Australia. Previously he taught in the Department of Anthropology at the University of New Mexico and in the Division of Human Development at the University of California, Davis. He is a biosocial anthropologist whose research interests lie in the fields of human behavioral biology, evolutionary ecology, and life history theory, where he focuses on infant social-emotional development and the development of reproductive strategies in adolescence and young adulthood. In addition to numerous articles he is the author ofNavajo Infancy: An Ethological Study of Child Development (Aldine de Gruyter, 1983).     

The ecology of sexual conflict: ecologically dependent parallel evolution of male harm and female resistance in Drosophila melanogaster

The prevalence of sexual conflict in nature, along with the potentially stochastic nature of the resulting coevolutionary trajectories, makes it an important driver of phenotypic divergence and speciation that can operate even in the absence of environmental differences. The majority of empirical work investigating sexual conflict's role in population divergence/speciation has therefore been done in uniform environments and any role of ecology has largely been ignored. However, theory suggests that natural selection can constrain phenotypes influenced by sexual conflict. We use replicate populations of Drosophila melanogaster adapted to alternative environments to test how ecology influences the evolution of male effects on female longevity. The extent to which males reduce female longevity, as well as female resistance to such harm, both evolved in association with adaptation to the different environments. Our results demonstrate that ecology plays a central role in shaping patterns of population divergence in traits under sexual conflict.     

Experimental evolution reveals differences between phenotypic and evolutionary responses to population density

Group living can select for increased immunity, given the heightened risk of parasite transmission. Yet, it also may select for increased male reproductive investment, given the elevated risk of female multiple mating. Trade‐offs between immunity and reproduction are well documented. Phenotypically, population density mediates both reproductive investment and immune function in the Indian meal moth, Plodia interpunctella. However, the evolutionary response of populations to these traits is unknown. We created two replicated populations of P. interpunctella, reared and mated for 14 generations under high or low population densities. These population densities cause plastic responses in immunity and reproduction: at higher numbers, both sexes invest more in one index of immunity [phenoloxidase (PO) activity] and males invest more in sperm. Interestingly, our data revealed divergence in PO and reproduction in a different direction to previously reported phenotypic responses. Males evolving at low population densities transferred more sperm, and both males and females displayed higher PO than individuals at high population densities. These positively correlated responses to selection suggest no apparent evolutionary trade‐off between immunity and reproduction. We speculate that the reduced PO activity and sperm investment when evolving under high population density may be due to the reduced population fitness predicted under increased sexual conflict and/or to trade‐offs between pre‐ and post‐copulatory traits.     

Beyond the phenotypic gambit: molecular behavioural ecology and the evolution of genetic architecture

Most studies of behaviour examine traits whose proximate causes include sensory input and neural decision-making, but conflict and collaboration in biological systems began long before brains or sensory systems evolved. Many behaviours result from non-neural mechanisms such as direct physical contact between recognition proteins or modifications of development that coincide with altered behaviour. These simple molecular mechanisms form the basis of important biological functions and can enact organismal interactions that are as subtle, strategic and interesting as any. The genetic changes that underlie divergent molecular behaviours are often targets of selection, indicating that their functional variation has important fitness consequences. These behaviours evolve by discrete units of quantifiable phenotypic effect (amino acid and regulatory mutations, often by successive mutations of the same gene), so the role of selection in shaping evolutionary change can be evaluated on the scale at which heritable phenotypic variation originates. We describe experimental strategies for finding genes that underlie biochemical and developmental alterations of behaviour, survey the existing literature highlighting cases where the simplicity of molecular behaviours has allowed insight to the evolutionary process and discuss the utility of a genetic knowledge of the sources and spectrum of phenotypic variation for a deeper understanding of how genetic and phenotypic architectures evolve.     

Colour spaces in ecology and evolutionary biology

The recognition that animals sense the world in a different way than we do has unlocked important lines of research in ecology and evolutionary biology. In practice, the subjective study of natural stimuli has been permitted by perceptual spaces, which are graphical models of how stimuli are perceived by a given animal. Because colour vision is arguably the best‐known sensory modality in most animals, a diversity of colour spaces are now available to visual ecologists, ranging from generalist and basic models allowing rough but robust predictions on colour perception, to species‐specific, more complex models giving accurate but context‐dependent predictions. Selecting among these models is most often influenced by historical contingencies that have associated models to specific questions and organisms; however, these associations are not always optimal. The aim of this review is to provide visual ecologists with a critical perspective on how models of colour space are built, how well they perform and where their main limitations are with regard to their most frequent uses in ecology and evolutionary biology. We propose a classification of models based on their complexity, defined as whether and how they model the mechanisms of chromatic adaptation and receptor opponency, the nonlinear association between the stimulus and its perception, and whether or not models have been fitted to experimental data. Then, we review the effect of modelling these mechanisms on predictions of colour detection and discrimination, colour conspicuousness, colour diversity and diversification, and for comparing the perception of colour traits between distinct perceivers. While a few rules emerge (e.g. opponent log–linear models should be preferred when analysing very distinct colours), in general model parameters still have poorly known effects. Colour spaces have nonetheless permitted significant advances in ecology and evolutionary biology, and more progress is expected if ecologists compare results between models and perform behavioural experiments more routinely. Such an approach would further contribute to a better understanding of colour vision and its links to the behavioural ecology of animals. While visual ecology is essentially a transfer of knowledge from visual sciences to evolutionary ecology, we hope that the discipline will benefit both fields more evenly in the future.     

Mimicry between unequally defended prey can be parasitic: evidence for quasi-Batesian mimicry

The nature of signal mimicry between defended prey (known as Müllerian mimicry) is controversial. Some authors assert that it is always mutualistic and beneficial, whilst others speculate that less well defended prey may be parasitic and degrade the protection of their better defended co-mimics (quasi-Batesian mimicry). Using great tits (Parus major) as predators of artificial prey, we show that mimicry between unequally defended co-mimics is not mutualistic, and can be parasitic and quasi-Batesian. We presented a fixed abundance of a highly defended model and a moderately defended dimorphic (mimic and distinct non-mimetic) species, and varied the relative frequency of the two forms of the moderately defended prey. As the mimic form increased in abundance, per capita predation on the model-mimic pair increased. Furthermore, when mimics were rare they gained protection from predation but imposed no co-evolutionary pressure on models. We found that the feeding decisions of the birds were affected by their individual toxic burdens, consistent with the idea that predators make foraging decisions which trade-off toxicity and nutrition. This result suggests that many prey species that are currently assumed to be in a simple mutualistic mimetic relationship with their co-mimic species may actually be engaged in an antagonistic co-evolutionary process.     

The evolutionary mechanism of cancer

Identification of the general molecular mechanism of cancer is the Holy Grail of cancer research. Since cancer is believed to be caused by a sequential accumulation of cancer gene mutations, the identification, characterization, and targeting of common genetic alterations and their defined pathways have dominated the field for decades. Despite the impressive data accumulated from studies of gene mutations, epigenetic dysregulation, and pathway alterations, an overwhelming amount of diverse molecular information has offered limited understanding of the general mechanisms of cancer. To solve this paradox, the newly established genome theory is introduced here describing how somatic cells evolve within individual patients. The evolutionary mechanism of cancer is characterized using only three key components of somatic cell evolution that include increased system dynamics induced by stress, elevated genetic and epigenetic heterogeneity, and genome alteration mediated natural selection. Cancer progression represents a macro‐evolutionary process where karyotype change or genome replacement plays the key dominant role. Furthermore, the recently identified relationship between the evolutionary mechanism and a large number of diverse individual molecular mechanisms is discussed. The total sum of all the individual molecular mechanisms is equal to the evolutionary mechanism of cancer. Individual molecular mechanisms including all the molecular mechanisms described to date are stochastically selected and unpredictable and are therefore clinically impractical. Recognizing the fundamental importance of the underlying basis of the evolutionary mechanism of cancer mandates the development of new strategies in cancer research. J. Cell. Biochem. 109: 1072–1084, 2010. © 2010 Wiley‐Liss, Inc.     

Genetic and environmental sources of covariance among internal reproductive traits in the yellow dung fly

Substantial inter- and intraspecific variation is found in reproductive traits, but the evolutionary implications of this variation remain unclear. One hypothesis is that natural selection favours female reproductive morphology that allows females to control mating and fertilization and that diverse male reproductive traits arise as counter adaptations to subvert this control. Such co-evolution predicts the establishment of genetic correlations between male and female reproductive traits that closely interact during mating. Therefore, we measured phenotypic and genetic correlations between male and female reproductive tract characteristics in the yellow dung fly, Scathophaga stercoraria (Diptera: Scathophagidae), using a nested half-sib breeding experiment. We found significant heritabilities for the size of most reproductive tract traits investigated in both females (spermathecae and their ducts, accessory glands and their ducts) and males (testis size but not sperm length). Within the sexes, phenotypic and genetic correlations were mostly nil or positive, suggesting functional integration of or condition-dependent investment in internal reproductive traits. Negative intrasexual genetic correlations, potentially suggestive of resource allocation trade-offs, were not evident. Intersexual genetic correlations were mostly positive, reflecting expected allometries between male and female morphologies. Most interestingly, testis size correlated positively with female accessory gland size and duct length, potentially indicative of a co-evolutionary arms race. We discuss these and alternative explanations for these patterns of genetic covariance.     

The evolution and ecology of masquerade

Many organisms appear to mimic inanimate objects such as twigs, leaves, stones, and bird droppings. Such adaptations are considered to have evolved because their bearers are misidentified as either inedible objects by their predators, or as innocuous objects by their prey. In the past, this phenomenon has been classified by some as Batesian mimicry and by others as crypsis, but now is considered to be conceptually different from both, and has been termed ‘masquerade’. Despite the debate over how to classify masquerade, this phenomenon has received little attention from evolutionary biologists. Here, we discuss the limited empirical evidence supporting the idea that masquerade functions to cause misidentification of organisms, provide a testable definition of masquerade, and suggest how masquerade evolved and under what ecological conditions. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 99 , 1–8.