Phylogenetics of the woodrat genus Neotoma (Rodentia: Muridae): implications for the evolution of phenotypic variation in male external genitalia

Interspecific morphological variation in animal genitalia has long attracted the attention of evolutionary biologists because of the role genital form may play in the generation and/or maintenance of species boundaries. Here we examine the origin and evolution of genital variation in rodents of the muroid genus Neotoma. We test the hypothesis that a relatively rare genital form has evolved only once in Neotoma. We use four mitochondrial and four nuclear markers to evaluate this hypothesis by establishing a phylogenetic framework in which to examine genital evolution. We find intron seven of the beta-fibrinogen gene to be a highly informative nuclear marker for the levels of differentiation that characterize Neotoma with this locus evolving at a rate slower than cytochrome b but faster than 12S. We estimate phylogenetic relationships within Neotoma using both maximum parsimony and maximum likelihood-based Bayesian methods. Our Bayesian and parsimony reconstructions differ in significant ways, but we show that our parsimony analysis may be influenced by long-branch attraction. Furthermore, our estimate of Neotoma phylogeny remains consistent across various data partitioning strategies in the Bayesian analyses. Using ancestral state reconstruction, we find support for the monophyly of taxa that possess the relatively rare genital form. However, we also find support for the independent evolution of the common genital form and discuss possible underlying developmental shifts that may have contributed to our observed patterns of morphological evolution.     

Past tree range dynamics in the Iberian Peninsula inferred through phylogeography and palaeodistribution modelling: A review

The forests in the Iberian Peninsula have been strongly influenced by past climatic changes, but reconstructing their historical distributions and dynamics is very difficult due to the complex climatic characteristics and relief of the region. Research disciplines such as phylogeography and species distribution modelling can describe the past range dynamics of individual tree species in relatively great detail and help elucidate how these species have reacted to climatic changes. Here we review phylogeographical and modelling studies from species representative of the major Iberian forest types and attempt to extract general trends from the diversity of individual species histories in the Peninsula. To date most studies focus on geographical range dynamics during the Pleistocene, but an increasing body of evidence shows that some species have also retained the genetic imprints of much more ancient processes. Many widespread Iberian species show a deep and often remarkably clear-cut divide between populations from the Mediterranean and from the Atlantic regions of the Iberian Peninsula, suggesting that both areas have independently sustained viable populations over extended periods. In fact, phylogeographical studies commonly find that species had several glacial refugia across the Iberian Peninsula. On the other hand, distribution models help identifying further suitable areas that could have sustained so far undetected refugia. Such studies are of interest for species conservation, because refugium populations are high-priority targets due to their long-term persistence and unique evolutionary trajectory. Overall, we conclude that palaeoecology, phylogeography and species distribution modelling have a great potential to inform each other because of their complementary perspectives and results. A true integration of these approaches is therefore fundamental for further progress in our understanding of past Iberian environments and the organisms they harboured.     

An estimate of avian mortality at communication towers in the United States and Canada

Avian mortality at communication towers in the continental United States and Canada is an issue of pressing conservation concern. Previous estimates of this mortality have been based on limited data and have not included Canada. We compiled a database of communication towers in the continental United States and Canada and estimated avian mortality by tower with a regression relating avian mortality to tower height. This equation was derived from 38 tower studies for which mortality data were available and corrected for sampling effort, search efficiency, and scavenging where appropriate. Although most studies document mortality at guyed towers with steady-burning lights, we accounted for lower mortality at towers without guy wires or steady-burning lights by adjusting estimates based on published studies. The resulting estimate of mortality at towers is 6.8 million birds per year in the United States and Canada. Bootstrapped subsampling indicated that the regression was robust to the choice of studies included and a comparison of multiple regression models showed that incorporating sampling, scavenging, and search efficiency adjustments improved model fit. Estimating total avian mortality is only a first step in developing an assessment of the biological significance of mortality at communication towers for individual species or groups of species. Nevertheless, our estimate can be used to evaluate this source of mortality, develop subsequent per-species mortality estimates, and motivate policy action.     

‘The Miserablest People in the World’: Race,Humanism and the Australian Aborigine

This paper considers how an idea of the Australian Aborigine impacted upon the development of racial thinking throughout the nineteenth century. We distinguish three phases of this development. Against the background of what was considered to be a distinctly human capacity to rise above nature, our central argument however is that the extreme and irremediable savagery attributed to the Aborigine led to the mid‐nineteenth shift to a polygenist, or an innatist, idea of race. The first part of our discussion, covering the early 1800s, elicits a specifically humanist puzzlement at the unimproved condition of the Aborigines. But, as we will show in the central part of our discussion, it was not only the Aborigines' inclination but their capacity for ‘improvement’ that came to be doubted. Challenging the very basis upon which ‘the human’ had been defined, and the unity of humankind assumed, the Aborigine could not be accommodated within a prevailing conception of racial difference as a mere variety of the human. The elaboration of polygenism may therefore be understood as arising out of this humanist incomprehension: as an attempt to account for the ontologically inexplicable difference of the Australian Aborigine. In the final part of our discussion, we trace the legacy of the Aborigine's place within polygenism through the evolutionary thought of the late nineteenth century. Despite an explicit return to monogenism, here the Aborigine is invoked to support the claim that race constitutes a more or less permanent difference and, for certain races, a more or less permanent deficiency. And as, in these terms, the anomalous Aborigine became an anachronism, so Australia's indigenous peoples came to embody the most devastating conclusion of evolutionary thought: that in the human struggle for existence certain races were destined not even to survive.     

Eavesdropping on visual secrets

Private communication may benefit signalers by reducing the costs imposed by potential eavesdroppers such as parasites, predators, prey, or rivals. It is likely that private communication channels are influenced by the evolution of signalers, intended receivers, and potential eavesdroppers, but most studies only examine how private communication benefits signalers. Here, we address this shortcoming by examining visual private communication from a potential eavesdropper’s perspective. Specifically, we ask if a signaler would face fitness consequences if a potential eavesdropper could detect its signal more clearly. By integrating studies on private communication with those on the evolution of vision, we suggest that published studies find few taxon-based constraints that could keep potential eavesdroppers from detecting most hypothesized forms of visual private communication. However, we find that private signals may persist over evolutionary time if the benefits of detecting a particular signal do not outweigh the functional costs a potential eavesdropper would suffer from evolving the ability to detect it. We also suggest that all undetectable signals are not necessarily private signals: potential eavesdroppers may not benefit from detecting a signal if it co-occurs with signals in other more detectable sensory modalities. In future work, we suggest that researchers consider how the evolution of potential eavesdroppers’ sensory systems influences private communication. Specifically, we suggest that examining the fitness correlates and evolution of potential eavesdroppers can help (1) determine the likelihood that private communication channels are stable over evolutionary time, and (2) demonstrate that undetectable signals are private signals by showing that signalers benefit from a reduction in detection by potential eavesdroppers.     

LINKING BIG: THE CONTINUING PROMISE OF EVOLUTIONARY SYNTHESIS

Synthetic science promises an unparalleled ability to find new meaning in old data, extant results, or previously unconnected methods and concepts, but pursuing synthesis can be a difficult and risky endeavor. Our experience as biologists, informaticians, and educators at the National Evolutionary Synthesis Center has affirmed that synthesis can yield major insights, but also revealed that technological hurdles, prevailing academic culture, and general confusion about the nature of synthesis can hamper its progress. By presenting our view of what synthesis is, why it will continue to drive progress in evolutionary biology, and how to remove barriers to its progress, we provide a map to a future in which all scientists can engage productively in synthetic research.     

Foraging zebra finches (Taeniopygia guttata) are public information users rather than conformists

Social learning enables adaptive information acquisition provided that it is not random but selective. To understand species typical decision-making and to trace the evolutionary origins of social learning, the heuristics social learners use need to be identified. Here, we experimentally tested the nature of majority influence in the zebra finch. Subjects simultaneously observed two demonstrator groups differing in relative and absolute numbers (ratios 1 : 2/2 : 4/3 : 3/1 : 5) foraging from two novel food sources (black and white feeders). We find that demonstrator groups influenced observers'' feeder choices (social learning), but that zebra finches did not copy the majority of individuals. Instead, observers were influenced by the foraging activity (pecks) of the demonstrators and in an anti-conformist fashion. These results indicate that zebra finches are not conformist, but are public information users.     

The ecology of social transitions in human evolution

We know that there are fundamental differences between humans and living apes, and also between living humans and their extinct relatives. It is also probably the case that the most significant and divergent of these differences relate to our social behaviour and its underlying cognition, as much as to fundamental differences in physiology, biochemistry or anatomy. In this paper, we first attempt to demarcate what are the principal differences between human and other societies in terms of social structure, organization and relationships, so that we can identify what derived features require explanation. We then consider the evidence of the archaeological and fossil record, to determine the most probable context in time and taxonomy, of these evolutionary trends. Finally, we attempt to link five major transitional points in hominin evolution to the selective context in which they occurred, and to use the principles of behavioural ecology to understand their ecological basis. Critical changes in human social organization relate to the development of a larger scale of fission and fusion; the development of a greater degree of nested substructures within the human community; and the development of intercommunity networks. The underlying model that we develop is that the evolution of ‘human society’ is underpinned by ecological factors, but these are influenced as much by technological and behavioural innovations as external environmental change.     

The Evolution of Human Brain Development

The human brain is a large and complex organ, setting us apart from other primates. It allows us to exhibit highly sophisticated cognitive and behavioral abilities. Therefore, our brain??s size and morphology are defining features of our species and our fossil ancestors and relatives. Endocasts, i.e., internal casts of the bony braincase, provide evidence about brain size and morphology in fossils. Based on endocasts, we know that our ancestors?? brains increased overall in size and underwent several reorganizational changes. However, it is difficult to relate evolutionary changes of size and shape of endocasts to evolutionary changes of cognition and behavior. We argue here that an understanding of the tempo and mode of brain development can help to interpret the evolution of our brain and the associated cognitive and behavioral changes. To do so, we review structural brain development, cognitive development, and ontogenetic changes of endocranial size and shape in living individuals on the one hand, and ontogenetic patterns (size increase and shape change) in fossil hominins and their evolutionary change on the other hand. Tightly integrating our knowledge on these different levels will be the key of future work on the evolution of human brain development.     

Energy, Calling, and Selection

SYNOPSIS. Acoustic signals often mediate the mating processand are under selection through the action of female choice.Acoustic signalling requires relatively large amounts of energyinput, but metabolic energy is coupled to acoustic energy inefficiently.Although not necessarily a cause and effect relationship, femalesoften prefer signals with more energy. Females may prefer moreintense calls, more complicated calls, or calls produced ata greater repetition rate. I discuss various evolutionary changesthat could increase acoustic energy received by the female andexamine how these changes are influenced by other factors inherentto communication systems: signal radiation, species recognition,sexual selection, the physiology of the receptor system, andenvironmental bioacoustics. I conclude that these factors constrainthe ability of the animal to maximize energy received by thefemale. I then consider how two hypotheses, the good genes hypothesisand the runaway sexual selection hypothesis, attempt to explainthe evolution of female choice for signals with greater energycontent.     

Evolutionary psychology of spatial representations in the hominidae

Comparatively little is known about the inherited primate background underlying human cognition, the human cognitive "wild-type." Yet it is possible to trace the evolution of human cognitive abilities and tendencies by contrasting the skills of our nearest cousins, not just chimpanzees, but all the extant great apes, thus showing what we are likely to have inherited from the common ancestor. By looking at human infants early in cognitive development, we can also obtain insights into native cognitive biases in our species. Here, we focus on spatial memory, a central cognitive domain. We show, first, that all nonhuman great apes and 1-year-old human infants exhibit a preference for place over feature strategies for spatial memory. This suggests the common ancestor of all great apes had the same preference. We then examine 3-year-old human children and find that this preference reverses. Thus, the continuity between our species and the other great apes is masked early in human ontogeny. These findings, based on both phylogenetic and ontogenetic contrasts, open up the prospect of a systematic evolutionary psychology resting upon the cladistics of cognitive preferences.     

Attitudes Toward Animals: Origins and Diversity

Abstract

It would be difficult to overestimate the significance of animals in the social and psychological life of our species. Images of animals are everywhere: in our language, religions, dreams, television programs, and folklore. The feelings that we exhibit toward our fellow creatures are intense, complex, and paradoxical. Responses to animals range from the disgust we feel when confronted with a bloated tick to the reverence for animals as deities in so-called primitive cultures; from the love of a child for a pet bunny to the paralyzing fear of phobic experiences when confronted by a harmless spider.

In recent years there has been increasing interest in human-animal relationships by investigators from a variety of disciplines. We will not attempt a synthesis of the growing literature on attitudes toward animals, but will follow a different course. For the past decade we have been exploring the diversity and origins of human-animal relationships, and our research has taken us into some rather odd places: cockfights in the United States and Latin America, slaughterhouses, and most recently, the world of supermarket check-out-counter magazines. In this article, we will summarize some of our findings and speculations that bear on the subject of attitudes toward animals. We will also briefly examine alternative methods of gathering information that do justice to the richness of human experience with animals.     

The influence of host hormones and cytokines on Echinococcus multilocularis signalling and development

Parasitic helminths display highly complex life-cycles in which the establishment of adults or larvae within host target organs as well as the transition of one developmental stage to the following is influenced by host-derived factors. Due to its approachability concerning in vitro cultivation, the larval stage of the fox-tapeworm Echinococcus multilocularis has recently emerged as a model system to study the molecular nature of such host-derived stimuli and their influence on developmental control in the parasite. Data obtained so far indicate that cytokines which are used by the host for cell-cell communication can also be exploited by the parasite as clues to find suitable target organs. This involves direct interactions of evolutionary conserved signalling systems of the receptor tyrosine--and the receptor serine/threonine-kinase pathways of the parasite with corresponding host cytokines of the insulin-, the epidermal growth factor-, and the transforming growth factor-beta-families. In the present article, we will briefly review in vitro cultivation approaches undertaken so far for E. multilocularis larvae as well as our current knowledge on the parasite's signalling systems and their interaction with host cytokines.     

Avian psychology and communication

The evolution of animal communication is a complex issue and one that attracts much research and debate. 'Receiver psychology' has been highlighted as a potential selective force, and we review how avian psychological processes and biases can influence the evolution and design of signals as well as the progress that has been made in testing these ideas in behavioural studies. Interestingly, although birds are a focal group for experimental psychologists and behavioural ecologists alike, the integration of theoretical ideas from psychology into studies of communication has been relatively slow. However, recent operant experiments are starting to address how birds perceive and respond to complex natural signals in an attempt to answer evolutionary problems in communication. This review outlines how a psychological approach to understanding communication is useful, and we hope that it stimulates further research addressing the role of psychological mechanisms in signal evolution.     

Communication in troubled waters: responses of fish communication systems to changing environments

Fish populations are increasingly being subjected to anthropogenic changes to their sensory environments. The impact of these changes on inter- and intra-specific communication, and its evolutionary consequences, has only recently started to receive research attention. A disruption of the sensory environment is likely to impact communication, especially with respect to reproductive interactions that help to maintain species boundaries. Aquatic ecosystems around the world are being threatened by a variety of environmental stressors, causing dramatic losses of biodiversity and bringing urgency to the need to understand how fish respond to rapid environmental changes. Here, we discuss current research on different communication systems (visual, chemical, acoustic, electric) and explore the state of our knowledge of how complex systems respond to environmental stressors using fish as a model. By far the bulk of our understanding comes from research on visual communication in the context of mate selection and competition for mates, while work on other communication systems is accumulating. In particular, it is increasingly acknowledged that environmental effects on one mode of communication may trigger compensation through other modalities. The strength and direction of selection on communication traits may vary if such compensation occurs. However, we find a dearth of studies that have taken a multimodal approach to investigating the evolutionary impact of environmental change on communication in fish. Future research should focus on the interaction between different modes of communication, especially under changing environmental conditions. Further, we see an urgent need for a better understanding of the evolutionary consequences of changes in communication systems on fish diversity.     

Pathways in the emergence of developmental neuroethology: antecedents to current views of neurobehavioral ontogeny.

The historical forces that have contributed to our current views of neurobehavioral development (and thus to the fields of developmental psychobiology and neuroethology) are many and varied. Although similar statements might be made about almost any field of science, it is in particular true of this field, which represents a kind of mongrel discipline derived from at least three major sources (psychology, embryology, and neuroscience) and several more minor ones (including developmental psychology and psychiatry, psychoanalysis, education, zoology, ethology, and sociology). Although I attempt to demonstrate here how each of these sources may have influenced the emergence of a unified field of developmental psychobiology or developmental neuroethology, because the present article represents the first attempt of which I am aware to trace the history of these fields I am certain that there is considerable room for improvement, correction, and revision of the views expressed here. Accordingly, I consider this inaugural effort a kind of reconnaissance intended to trace a necessarily imperfect historic path for others to follow and improve upon. In the final analysis, I will be satisfied if this article only serves to underscore two related points: first is the value derived from historical studies of contemporary issues in development, and the second concerns the extent to which our current ideas and concepts about neurobehavioral development, ideas often considered new and contemporary, were already well known to those who came before us. The first point underscores the arguments expressed in the Introduction that the present must always be reconciled with the past, for the past is never entirely past. The second point returns full circle to an important thought expressed in the opening quotation to this article, namely, that even though our historic predecessors lacked much of the empirical facts available to us they were nonetheless able to attain a surprisingly deep understanding of neurobehavioral ontogeny.     

Evolution of genetically correlated traits: tooth size and body size in baboons

Within a population, only phenotypic variation that is influenced by genes will respond to selection. Genes with pleiotropic effects are known to influence numerous traits, complicating our understanding of their evolution through time. Here we use quantitative genetic analyses to identify and estimate the shared genetic effects between molar size and trunk length in a pedigreed, breeding population of baboons housed at the Southwest National Primate Research Center. While crown area has a genetic correlation with trunk length, specific linear measurements yield different results. We find that variation in molar buccolingual width and trunk length is influenced by overlapping additive genetic effects. In contrast, mesiodistal molar length appears to be genetically independent of body size. This is the first study to demonstrate a significant genetic correlation between tooth size and body size in primates. The evolutionary implications are discussed.     

Alpha-L-fucosidases: exoglycosidases with unusual transglycosylation properties

Apha-LFucosidases (EC 3.2.1.51), the only members of the CAZy family GH-29, are widespread glycosidases involved in many biological processes including inflammation, metastasis, and the lysosomal storage disease fucosidosis. Despite their biological significance, information concerning the mechanism of alpha-Lfucosidases has only recently become available. In an attempt to obtain further data concerning their mechanism, we have investigated the hydrolytic and transglycosylation properties of a canine and a mollusk (Pecten maximus) alpha-Lfucosidase. Our results show that, despite the evolutionary distance between these two species, both enzymes have similar hydrolysis and transglycosylation properties. Surprisingly, we found that, starting from monosaccharides, these exoglycosidases were able to catalyze efficiently the synthesis of highly branched fuco-oligosaccharides as large as tetrasaccharides, a unique feature for a wild-type exoglycosidase. The structural analysis of the compounds formed revealed that the regioselectivity of alpha-Lfucosidases is strongly influenced by the structure of the acceptor. This leads us to propose an enzymatic approach for the preparative synthesis of fuco-oligosaccharides. This will not only allow the synthesis of biological determinants containing fucose but also of new fucose-containing oligosaccharides as alpha-glycosynthases appear to be difficult to obtain.