A social learning model of conflict and cooperation in human societies

Patterns of conflict and cooperation both within and between societies may be related to the degree of cultural similarity within and between the same societies. A simple model of social learning is used to predict patterns of conflict and cooperation in hypothetical societies that differ in the roles of relatives and nonrelatives in the enculturation of children. The model is illustrated by comparing its predictions to known differences in the patterns of conflict between males inpatrilocal and matrilocal societies.     

Evolutionary assembly of cooperating cell types in an animal chemical defense system

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PHYLOGENETIC ANALYSIS OF THE EVOLUTION OF ALTERNATIVE SOCIAL BEHAVIOR IN THE MANAKINS (AVES: PIPRIDAE)

Phylogenetic analyses of lekking, lek spatial organization, and cooperative and coordinated lek display in the manakins (Aves: Pipridae) demonstrate that variation in social behavior in the group has a strong, phylogenetic component. Two of the three classes of social behavior examined also show significant phylogenetic constraints. Current adaptive plasticity models are insufficient to explain the phylogenetic variation in these behaviors in the manakins. These findings support the conclusion that vertebrate reproductive social behavior has an evolutionary history, and that it is not determined solely by adaptive individual plasticity to current conditions. The evolution of social behavior, particularly through sexual selection, can have historical consequences that can limit subsequent behavioral adaptation.     

Effect of biological toxins on gap-junctionai intercellular communication in Chinese hamster V79 cells

Since chemical modulation of gap junctional intercellular communication has been implicated in several toxicological endpoints, a study to examine the ability of several biological toxins to inhibit this process was undertaken. Eight biological toxins were tested for their ability to inhibit metabolic cooperation, a measure of gap-junctional intercellular communication, in the Chinese V79 cell system. Aplysiatoxin, anhydrodebromoaplysiatoxin and debromoaplysiatoxin showed the strongest ability to inhibit metabolic cooperation while T2-toxin and vomitoxin inhibited metabolic cooperation to a lesser degree. Afatoxin B₁, afatoxin B₂ and palytoxin were inactive in the Chinese V79 system. Palytoxin, which was extremely cytotoxic, might act as a tumor promoter if it induces compensatory hyperplasia in vivo.Abbreviations 6-TG 6-thioguanine - TPA 12-0-tetradecanoylphorbol-13-acetate     

Monogamy to communal breeding: exploitation of a broad resource base by burying beetles (Nicrophorus)

Abstract.

• 1 To investigate the range of resource size that burying beetles (Nicrophorus) exploit, small (21–33 g), medium (50–90 g) and large (120–210g) carcasses, were placed in the field and then exhumed after 1, 4, 8, 12 or 18 days.
• 2 Nicrophorus attempts to utilize carcasses over this entire size range but has greater success on smaller carcasses.
• 3 Larger carcasses were more difficult to exploit because: (a) they took longer to conceal beneath the leaf litter; (b) they were less likely to be rounded into brood balls; (c) they were more likely to be utilized by dipterans; and (d) they were occupied by greater numbers of congeners.
• 4 Larger carcasses, however, did support greater numbers of larvae and contained broods of greater total mass than smaller carcasses.
• 5 Beetles sometimes bred communally on larger carcasses in the field and same-sex adults were observed to feed young.
• 6 Two follow-up experiments were conducted in the laboratory. On a large carcass N.defodiens, N.tomentosus or N.orbicollis can raise a maximum of 35–50 young. Nicrophorus pustulatus, in contrast, appears to be unique among Nicrophorus in that it can raise nearly 200 young on larger carcasses.
• 7 Nicrophorus orbicollis and Nicrophorus sayi are extremely dependent on parental regurgitations and young fail to survive to the second instar if parents are removed. Young of Nicrophorus defodiens, N.tomentosus and N.pustulatus can develop normally without parental regurgitations.
• 8 I discuss these results in the context of reproduction on carcasses of different size and hypothesize that this breeding system is facultatively quasisocial.

     

Oncogene expression in mammary epithelial cells.

Mouse strains which develop tumors at a high incidence with characteristics very similar to human cancers have been derived over the last 8 years. The tumors are caused by defined genetic alterations in the mouse genome. Three areas of research have contributed to the derivation of these mouse strains: (1) Molecular analysis of human tumors has shown that distinct oncogenes and tumor suppressor genes are consistently involved in a high percentage of primary tumors. (2) Regulatory enhancer-promoter sequences have been identified which direct gene expression to specific target cells, preferentially mammary epithelial cells. (3) The introduction of recombinant DNA molecules into fertilized mouse eggs by microinjection and integration of the injected DNA into the genome of injected cells has given rise to mutant mouse strains with unique and defined genetic alterations. Studies with different promoter-oncogene combinations introduced into transgenic mouse strains have led to the following general conclusions: (1) Oncogenes expressed in mammary gland cells predispose transgenic mice to mammary tumors. (2) The oncogenic potential of individual oncogenes in mammary epithelial cells differs. (3) Oncogene expression initially often causes a preneoplastic state affecting growth and differentiation parameters of cells. (4) The expression of different oncogenes synergizes to reduce tumor latency. Synergism can also be observed with physiological growth signals like estrogen or growth hormone. The oncogenes with a role in mammary carcinomas which have been investigated in transgenic mice will be described here. The phenotypic consequences of oncogene expression and the implications for the multistep carcinogenesis model will be discussed.     

欺骗,契约,合作的ESS

动物竞争中的欺骗、契约、合作现象是极为常见的。本文就论述与此有关的ESS。一、欺骗某些动物竞争时信号a后跟随发生行为A,如一个体不出现A则为欺骗。欺骗是相对真实     

Effects of phorbol myristate acetate,phorbol dibutyrate,ethanol, dimethylsulfoxide,phenol, and seven metabolities of phenol on metabolic cooperation between chinese hamster v79 lung fibroblasts

The effect of phorbol myristate acetate, phorbol dibutyrate, ethanol, dimethylsulfoxide, phenol, and seven metabolites of phenol on metabolic cooperation were assessed as a function of mutant cell recovery from populations of cocultivated hypoxanthine-guanine phosphoribosyl transferase-deficient mutant (HGPRT–) and wild-type (HGPRT+) Chinese hamster V79 lung fibroblasts. Phorbol myristate acetate and phorbol diputyrate, two established tumor promoters, were potent inhibitors of metabolic cooperation. Ethanol and dimethylsulfoxide, solvents commonly used to prepare chemicals for testing, weakly inhibited metabolic cooperation. Phenol and phenylglucuronide had no effect on metabolic cooperation. Four oxidative metabolites (1,4-benzoquinone, catechol, hydroxyquinol and quinol) inhibited metabolic cooperation. Phenylsulfate weakly inhibited metabolic cooperation. Conversely, 2-methoxyphenol, a methylated derivative of catechol, appeared to enhance metabolic cooperation. These results generallyAbbreviations CAS Chemical Abstracts Service - DMSO dimethylsulfoxide - ETOH ethanol - HGPRT hypoxanthine-guanine phosphoribosyl transferase - HGPRT+ HGPRT-competent - HGPRT– HGPRT-te]deficient - MC metabolic cooperation - MC+ metabolic cooperation-competent - MC– metabolic cooperation-deficient - MEM minimum essential medium - PDBu phorbol dibutyrate - PMA phorbol myristate acetate - 6TG 6-thioguanine - 6TG^r 6-thioguanine-resistant - 6TG^s 6-thioguanine-sensitive - V79/MC assay Chinese hamster V79 lung fibroblast assay for metabolic cooperation     

Shifts in macrophyte species composition as a result of eutrophication and pollution in Dutch transboundary streams over the past decades

The catchment areas of transboundary streams in the Netherlands have been subject to increasing agricultural and industrial activities over the past decades. To evaluate the effects of these activities on the aquatic vegetation, a study has been carried out in 28 Dutch transboundary lowland streams. Recent data on distribution of 58 aquatic plant species and their growth forms were compared with historical data and were correlated with abiotic variables. Most of these streams lost species that are characteristic for streams and are sensitive to turbidity, eutrophication and pollution (e.g. Potamogeton alpinus, P. polygonifolius, P. densus, Ranunculus peltatus ssp. heterophyllus, Callitriche stagnalis and Myriophyllum alterniflorum.) Species, not common in streams but tolerant to turbidity, eutrophication or pollution (e.g. Potamogeton trichoides, Elodea nuttallii) appeared in many streams or increased in abundance. There was also a shift in growth forms: submerged species decreased or were replaced by emergent/floating-leaved species. Correspondence analysis was carried out to study the relation between the observed changes and the abiotic characteristic of the streams. The magnitude of the shift in species composition was positively correlated with the PO₄ ^3- concentration and pH (which was highly correlated with Cd²⁺) of the water. This leads to the hypothesis that increased input of sewage, agricultural and industrial water causes a change in species composition and main growth forms of aquatic plant species in lowland streams.     

The role of cross-border transhumance in influencing resident herders’ cattle husbandry practices and use of genetic resources

For centuries, the humid West African coastal country of Benin attracts cattle herders from neighboring Sahelian countries such as Niger, Burkina Faso and Nigeria. Each year, several thousands of cattle are trekked over hundreds of kilometers to Benin following established and non-established transhumance corridors. This cross-border mobility has been shown to play an important role in ensuring the productivity of the transhumant herds through adequate late dry season access to pastoral resources. Yet, its effects on the traditional agro-pastoral production systems that are encountered along the routes in Benin have never been explicitly investigated. Therefore, we collected socio-economic household data, herd characteristics and management data from 104 resident herders and 38 transhumant herders in 2 vegetation zones of Benin. To determine whether or not the proximity to transhumance corridors affects sedentary production systems, characteristics of cattle herds and farmers’ management practices were compared between villages close to (within a 25 km buffer) and far from (outside a 25 km buffer) transhumance corridors within and between vegetation zones using non-parametric statistical tests. Existing relationships between resident and transhumant herders were also identified and characterized. Subsequently, herd characteristics and management practices were compared between resident herders having relationships with transhumant herders and those without. Herd sizes of resident herders living close to transhumance corridors were larger (P < 0.01) than those of their counterparts living far away. Also, proximity to transhumance corridors had positive effects on herd management practices. The relationships between resident and transhumant herders were governed by a variety of interests including encampment/manuring contracts, exploitation of grazing lands and watering points, trading and bartering of cattle. This exchange of cattle is an important driver of change in the breed composition of local herds and represents an opportunity for resident herders to enhance their herds’ productivity through crossbreeding. However, the mere replacement or indiscriminate crossbreeding of local cattle breeds with those kept by transhumant herders threatens the sustainability of the traditional resident herding systems by increasing the risk of genetic erosion and loss of valuable adaptive traits in indigenous animal genetic resources.