The Behavioral Ecology of Color Vision: Considering Fruit Conspicuity,Detection Distance and Dietary Importance

Primate color vision is well suited for investigating the genetic basis of foraging behavior owing to a clear genotype–phenotype linkage. Finding fruits amid tropical foliage has long been proffered as an adaptive explanation for primate trichromacy, yet there is a dearth of systematic evaluations of frugivory as an ecological selective force. We studied the behavioral ecology of wild capuchins (Cebus capucinus) in northwestern Costa Rica across the annual cycle and modeled the ability of three dichromatic and three trichromatic phenotypes to discriminate fruits from leaves, a task that represents long-distance search for food patches in a tropical forest. Models of the trichromatic phenotypes could correctly discriminate approximately three-quarters of the total capuchin dietary fruits from leaves, including some fruits subjectively classified as having “cryptic” (greenish-brownish) hues. In contrast, models of dichromatic phenotypes could discriminate fewer than one-third of the fruits. This pattern held when we restricted our analysis to only the most heavily consumed diet items, preferred foods, or seasonally critical species. We in addition highlight the potential of fruit species with small patch sizes to confer an advantage to trichromats, as these resources are anticipated to provide a high finder’s reward. Our results are consistent with the hypothesis that long-distance detection of fruit patches exerts a selective pressure on trichromacy in neotropical primates, and suggest that greenish-brownish fruits might have played an underappreciated role in the evolution of primate color vision.     

Assassination and Conflict Resolution in Laos

Ten cases of political homicide in Laos were intensively studied, with particular attention to the assassin, the victim, the homicidal event, the provocation, and the social context. Each assassination provided a resolution for a social dilemma which had proven refractory to other means of social problem solving. Certain demographic characteristics and psycho-social correlates of political homicide in Laos resemble those of other cultures.     

Conflict Resolution in Chimpanzees and the Valuable-relationships Hypothesis

Reconciliation, or peaceful postconflict interaction, can restore the usual pattern of interaction between social partners after open conflict has disrupted it—i.e., it can resolve conflicts. Researchers have documented reconciliation in >20 primate species, but the tendency to reconcile typically varies among dyads and dyad classes. The valuable-relationships hypothesis proposes that differences in the value of social relationships account for much of this variation. Value depends on how likely partners are to act in ways that benefit each other, where the benefits are ultimately direct or indirect increases in fitness. Researchers have responded to studies that have tested predictions of the hypothesis with extensive, if not universal, support. For example, kin show higher conciliatory tendencies than nonkin in many species, and conciliatory tendencies between unrelated females are high in several cercopithecines in which nonkin agonistic support is important for rank acquisition and maintenance. However, most of the support is indirect, because we lack direct evidence on the link between assays of relationship value and fitness. Also, some studies have methodological weaknesses, e.g., analyses based on pooled data and insufficient sample sizes. I review evidence in favor of the hypothesis with special attention to studies that come closest to providing evidence for predicted fitness effects. I also present new data on postconflict interactions between adult male chimpanzees at Ngogo that show how often pairs of males formed coalitions and how much time they spent grooming influenced the likelihood that they would reconcile after conflicts, and that allies were particularly likely to reconcile and to do so by grooming each other. The most important future research direction is to integrate detailed data on conflict management, analyzed at the level of dyads, with long-term data on reproductive success, such as that now available from several study sites, on the same populations.     

Placebo-Suggestion Modulates Conflict Resolution in the Stroop Task

Here, we ask whether placebo-suggestion (without any form of hypnotic induction) can modulate the resolution of cognitive conflict. Naïve participants performed a Stroop Task while wearing an EEG cap described as a “brain wave” machine. In Experiment 1, participants were made to believe that the EEG cap would either enhance or decrease their color perception and performance on the Stroop task. In Experiment 2, participants were explicitly asked to imagine that their color perception and performance would be enhanced or decreased (non-hypnotic imaginative suggestion). We observed effects of placebo-suggestion on Stroop interference on accuracy: interference was decreased with positive suggestion and increased with negative suggestion compared to baseline. Intra-individual variability was also increased under negative suggestion compared to baseline. Compliance with the instruction to imagine a modulation of performance, on the other hand, did not influence accuracy and only had a negative impact on response latencies and on intra-individual variability, especially in the congruent condition of the Stroop Task. Taken together, these results demonstrate that expectations induced by a placebo-suggestion can modulate our ability to resolve cognitive conflict, either facilitating or impairing response accuracy depending on the suggestion’s contents. Our results also demonstrate a dissociation between placebo-suggestion and non-hypnotic imaginative suggestion.     

Assessing Costs of Reproduction in Mountain Birch: The Importance of Considering the Modular Level

We studied the effects of production of male catkins on growthand the subsequent year's male catkin production in mountainbirch, Betula pubescens subsp. czerepanovii at both the shootand branch level. (Shoot is defined here as the product of asingle growing season while branch refers to a structure consistingof several shoots.) Like heterophyllous trees in general, mountainbirch canopy expansion takes place via the production of longshoots. We found phenotypic trade-offs between long shoot growthand male reproduction at the shoot level in the year of catkinproduction. Generative parental long shoots (long shoots withmale catkins) were significantly shorter than the vegetativeones (long shoots without a male catkin). In contrast, we foundno effects of male reproduction on the subsequent year's malecatkin production at the shoot level. Although the mean lengthof secondary long shoots (long shoots growing from the lateralbuds of parental long shoots) did not differ between vegetativeand generative parental long shoots, there was considerablebetween-individual variation in the response of individual trees.In addition, production of male catkins diminishes canopy expansionin mountain birch because the number of secondary long shootsproduced by generative parental long shoots was smaller thanthat of vegetative parental long shoots. At the branch level,the association between total long shoot growth and male catkinproduction was positive, i.e. no trade-off was found. This maybe because the strong sink strength (the ability of a branchto import assimilates from elsewhere in the tree) of branchesbearing reproductive long shoots masks possible trade-offs.We emphasize the importance of considering several levels ofthe modular hierarchy when analysing costs of reproduction inmodular organisms. Copyright 2000 Annals of Botany Company Hierarchical structure, modularity, mountain birch, short and long shoots, trade-off, Betula pubescens subsp.czerepanovii (Orlova) Hämet-Ahti     

The Importance of Behavioral Plasticity for Maximizing Foraging Efficiency in Frugivorous Lepidopteran Larvae

In this study, we present evidence that the larvae of Acrobasis vaccinii (Lepidoptera: Pyralidae), a species that feeds on cranberry fruit, are able to take into account at least three cues (fruit size, fruit color, and the distance between fruits) when searching for food. In laboratory experiments, the relative impact of each cue depended on which cues were presented in a given bioassay. Fruit color was the dominant cue in some contexts (e.g., larvae showed a significant perference for green fruit over red ones regardless of fruit size when fruits were equidistant from the larvae) but not in others (e.g., when given a choice between a large red fruit placed close to the larvae and a small green fruit placed farther away, a significantly higher proportion of larvae chose the former). This plasticity in foraging behavior allows larvae to maximize foraging efficiency under conditions of differing fruit and larval densities, which this species experiences in nature.     

Predation–Reproduction Conflict Resolution in the Hermit Crab, Clibanarius vittatus

Activities associated with courtship are often in conflict with avoiding elevated predation risk. In polygamous species with temporally restricted mating seasons, males should be less responsive to interruption of courtship by detection of elevated predation risk compared to females. We tested this prediction with the hermit crab Clibanarius vittatus. Courting males continued to execute pre‐copulatory behavior patterns when exposed to predator odors. However, in the presence of predator odors, fewer pairs were established. Exposing previously paired males and females to predator cues showed that males were unaffected in their motivation to form pairs, whereas females were no longer attractive to males following exposure to predator cues.     

篮状菌属的重要性及其分类学研究概况

篮状菌Talaromyces是一类广泛分布于自然界及人类活动场所的腐生真菌,它们与植物、动物和人类有着相当密切的关系.篮状菌最初被当作青霉Penicillium来研究,但后来的分子种系学研究表明篮状菌与青霉差异较大,分属于不同的科.篮状菌属目前可分8个组,全球已报道该属共162种,我国已报道57种.对篮状菌属的重要性、...     

Keeping the Peace: Conflict Resolution and Peaceful Societies around the World

Keeping the Peace: Conflict Resolution and Peaceful Societies around the World . Graham Kemp and Douglas P. Fry, eds. New York: Routledge, 2004. 231 pp.     

Cross-Modal Stimulus Conflict: The Behavioral Effects of Stimulus Input Timing in a Visual-Auditory Stroop Task

Cross-modal processing depends strongly on the compatibility between different sensory inputs, the relative timing of their arrival to brain processing components, and on how attention is allocated. In this behavioral study, we employed a cross-modal audio-visual Stroop task in which we manipulated the within-trial stimulus-onset-asynchronies (SOAs) of the stimulus-component inputs, the grouping of the SOAs (blocked vs. random), the attended modality (auditory or visual), and the congruency of the Stroop color-word stimuli (congruent, incongruent, neutral) to assess how these factors interact within a multisensory context. One main result was that visual distractors produced larger incongruency effects on auditory targets than vice versa. Moreover, as revealed by both overall shorter response times (RTs) and relative shifts in the psychometric incongruency-effect functions, visual-information processing was faster and produced stronger and longer-lasting incongruency effects than did auditory. When attending to either modality, stimulus incongruency from the other modality interacted with SOA, yielding larger effects when the irrelevant distractor occurred prior to the attended target, but no interaction with SOA grouping. Finally, relative to neutral-stimuli, and across the wide range of the SOAs employed, congruency led to substantially more behavioral facilitation than did incongruency to interference, in contrast to findings that within-modality stimulus-compatibility effects tend to be more evenly split between facilitation and interference. In sum, the present findings reveal several key characteristics of how we process the stimulus compatibility of cross-modal sensory inputs, reflecting stimulus processing patterns that are critical for successfully navigating our complex multisensory world.     

The Importance of Stimulus Noise Analysis for Self-Motion Studies

Motion simulators are widely employed in basic and applied research to study the neural mechanisms of perception and action during inertial stimulation. In these studies, uncontrolled simulator-introduced noise inevitably leads to a disparity between the reproduced motion and the trajectories meticulously designed by the experimenter, possibly resulting in undesired motion cues to the investigated system. Understanding actual simulator responses to different motion commands is therefore a crucial yet often underestimated step towards the interpretation of experimental results. In this work, we developed analysis methods based on signal processing techniques to quantify the noise in the actual motion, and its deterministic and stochastic components. Our methods allow comparisons between commanded and actual motion as well as between different actual motion profiles. A specific practical example from one of our studies is used to illustrate the methodologies and their relevance, but this does not detract from its general applicability. Analyses of the simulator’s inertial recordings show direction-dependent noise and nonlinearity related to the command amplitude. The Signal-to-Noise Ratio is one order of magnitude higher for the larger motion amplitudes we tested, compared to the smaller motion amplitudes. Simulator-introduced noise is found to be primarily of deterministic nature, particularly for the stronger motion intensities. The effect of simulator noise on quantification of animal/human motion sensitivity is discussed. We conclude that accurate recording and characterization of executed simulator motion are a crucial prerequisite for the investigation of uncertainty in self-motion perception.     

Mefloquine Blockade of Pannexin1 Currents: Resolution of a Conflict

Abstract

The authors’ laboratory has reported potent block of Pannexin1 (Panx1) currents by the antimalarial quinine derivative mefloquine. However, other laboratories have found little or no mefloquine sensitivity of Panx1 currents or processes attributable to these channels. In order to resolve this issue, the authors have performed extensive dose-response studies on Panx1-transfected neuroblastoma (Neuro2A) and rat insulinoma (Rin) cells, comparing mefloquine obtained from three suppliers and also comparing the sensitivity to diastereomers. Results indicate a 20-fold difference in sensitivity to the (?)-threo-(11R/2R) diastereomer compared to the erythro enatiomers and much lower potency of (±)-erythro-(R*/S*)-mefloquine obtained from one of the commercial sources. This markedly lower efficacy presumably accounts for the disparity in results from different laboratories who have applied it in Panx1 studies.     

Anatomical and Behavioral Differences Among Threespine Sticklebacks: the Marine Form,the Landlocked Form and Their Hybrids

In order to elucidate the mechanisms and degree of isolation in the landlocked form of the threespine stickleback, Gasterosteus aculeatus (L.), inhabiting the Shinano and Agano Rivers that flow into the Japan Sea, comparative studies on the morphology, behavior and histology were made of the marine form, the landlocked form and their hybrids reared in the laboratory. The body shape, coloration and behavior of reciprocal hybrids were almost intermediate between the two parent forms. From January to February, the testis of the hybrid between the female marine form and the male landlocked form is occupied exclusively by spermatocytes and some spermatids. However, a small number of large cells, identified as macrophages, are found invading the seminiferous tubules, indicating the occurrence of phagocytosis. On the other hand, ripe functional eggs appear in the ovary in May, i.e. the breeding season. The eggs deposited into the nest do not develop even when the hybrids display the same mating behavior as their parents. Functional sperms are found in the testis of the hybrid between female landlocked and male marine forms at the period of breeding. However, only a single female lived until March. In the ovary of this female, all eggs reaching vitellogenesis (= primary yolk globule stage) are collapsed, while the younger oocytes appear in healthy condition. The hybrid female of this pairing seemed also to be sterile.     

Low Resolution Solution Structure of HAMLET and the Importance of Its Alpha-Domains in Tumoricidal Activity

HAMLET (Human Alpha-lactalbumin Made LEthal to Tumor cells) is the first member in a new family of protein-lipid complexes with broad tumoricidal activity. Elucidating the molecular structure and the domains crucial for HAMLET formation is fundamental for understanding its tumoricidal function. Here we present the low-resolution solution structure of the complex of oleic acid bound HAMLET, derived from small angle X-ray scattering data. HAMLET shows a two-domain conformation with a large globular domain and an extended part of about 2.22 nm in length and 1.29 nm width. The structure has been superimposed into the related crystallographic structure of human α-lactalbumin, revealing that the major part of α-lactalbumin accommodates well in the shape of HAMLET. However, the C-terminal residues from L105 to L123 of the crystal structure of the human α-lactalbumin do not fit well into the HAMLET structure, resulting in an extended conformation in HAMLET, proposed to be required to form the tumoricidal active HAMLET complex with oleic acid. Consistent with this low resolution structure, we identified biologically active peptide epitopes in the globular as well as the extended domains of HAMLET. Peptides covering the alpha1 and alpha2 domains of the protein triggered rapid ion fluxes in the presence of sodium oleate and were internalized by tumor cells, causing rapid and sustained changes in cell morphology. The alpha peptide-oleate bound forms also triggered tumor cell death with comparable efficiency as HAMLET. In addition, shorter peptides corresponding to those domains are biologically active. These findings provide novel insights into the structural prerequisites for the dramatic effects of HAMLET on tumor cells.     

The Importance of Understanding the Chemical Form of a Metal in the Environment: The Case of Barium Sulfate (Barite)

Environmental assessments of metals are often simplified by referring to metals in terms of their elemental names without further consideration of specific metal compounds. Such simplifications can obscure important information on the fate and effects of the particular metal compounds. Barium sulfate (barite) provides a good example of the importance of knowing the specific compound when evaluating exposure, effects, and risks. We illustrate this by comparing the solubility and toxicity of barite to the soluble barium salts used to derive the U.S. Environmental Protection Agency barium ecological soil screening levels (Eco-SSLs). For ecologically relevant exposure pathways, the toxicity of barium compounds is largely controlled by their solubility. In contrast to soluble barium salts (e.g., barium acetate, barium chloride, and barium nitrate), barite is sparingly soluble and practically nontoxic to invertebrates, plants, or wildlife. No-effect levels for soil invertebrates (17,000 to 1,000,000 mg/kg) are several orders of magnitude higher than the barium Eco-SSL for soil invertebrates (330 mg/kg). And, low solubility likely limits the bioaccumulation of barium associated with barite and potential for effects on wildlife species. The importance of knowing the form of a metal compound is underscored by the fact that barite is one of the most commonly occurring barium compounds in soils and is widely used in commerce. The large differences between barite and the soluble barium compounds used to derive the Eco-SSL indicate that this screening tool cannot be usefully applied to soils containing the most commonly found barium compound, barite. The value of considering the specific metal compounds present in exposure media applies to other metals and indicates a need to go beyond simplified characterizations of metals expressed solely in terms of their elemental names.     

Behavioral and Electrophysiological Studies on Chemoreception in Aplysia

Using the typical mouth opening response (MOR) as the indexof chemore-ception, several amino acid constituents of naturalfood for Aplysia were effective in eliciting MOR in concentrationsas low is 10^–6 10^–7 M (glutamic acid) and 10^–510^–6 M (aspartic acid). It was suggested that these substancesmay serve as food attractants for this animal. Combined resultsof behavioral and electrophysiological experiments indicatedthat the most sensitive food receptors of Aplysia are predominantlylocated in the anterior tentacular groove area of the oral veil.These receptors appeared to strongly project to the caudal darkcell clusters of the cerebral ganglion. Extracellular recordingof single afferent units following oral veil stimulation withvarious chemicals showed that the chemoreceptors in the anteriortentacular groove area were 100 to 1000 times more sensitiveto food substances than other stimuli tested. It was suggestedthat these receptors are relatively "specific" to food attractants.There was a correlation between behavioral and electrophysiologicalthreshold data for the individual compounds. The electrophysiologicalthresholds however were 5–15 times higher than the behavioralthresholds.     

Long-Term Cognitive and Behavioral Outcomes following Resolution of Sleep Disordered Breathing in Preschool Children

This study aimed to determine the long term effects of resolution of SDB in preschool children, either following treatment or spontaneous recovery, on cognition and behavior. Children diagnosed with SDB at 3-5y (N = 35) and non-snoring controls (N = 25), underwent repeat polysomnography (PSG) and cognitive and behavioral assessment 3 years following a baseline study. At follow-up, children with SDB were grouped into Resolved and Unresolved. Resolution was defined as: obstructive apnea hypopnea index (OAHI) ≤1 event/h; no snoring detected on PSG; and no parental report of habitual snoring. 57% (20/35) of children with SDB received treatment, with SDB resolving in 60% (12/20). 43% (15/35) were untreated, of whom 40% (6/15) had spontaneous resolution of SDB. Cognitive reduced between baseline and follow-up, however this was not related to persistent disease, with no difference in cognitive outcomes between Resolved, Unresolved or Control groups. Behavioral functioning remained significantly worse in children originally diagnosed with SDB compared to control children, regardless of resolution. Change in OAHI did not predict cognitive or behavioral outcomes, however a reduction in nocturnal arousals, irrespective of full resolution, was associated with improvement in attention and aggressive behavior. These results suggest that resolution of SDB in preschool children has little effect on cognitive or behavioral outcomes over the long term. The association between sleep fragmentation and behavior appears independent of SDB, however may be moderated by concomitant SDB. This challenges the assumption that treatment of SDB will ameliorate associated cognitive and behavioural deficits and supports the possibility of a SDB phenotype.     

豆科植物在中国草原生态系统中的地位及其生理生态研究

豆科(Leguminosae)植物在改良土壤肥力、保持水土、提供多种经济产品方面功能显著,但我国干旱、半干旱草原区草场的退化使豆科植物资源受到严重破坏,有的面临灭绝的危险.本文明确了豆科植物在草原生态系统中的重要性,并综述了其光合、固氮等重要生理过程的研究进展,总结出自然生态系统中豆科植物的高光合机理和环境胁迫对固氮特性的影响,同时指出在豆科植物的适生机制和固氮潜能的发挥等还有很大的研究前景,在生产实践中,播种豆科灌木和豆科牧草是解决大面积人工林、草场"氮缺乏"的有效措施.