Predation on primates: Ecological patterns and evolutionary consequences

It has long been thought that predation has had important ecological and evolutionary effects on primates as prey. Predation has been theorized to have been a major selective force in the evolution of hominids.¹ In modern primates, behaviors such as active defense, concealment, vigilance, flight, and alarm calls have been attributed to the selective pressures of predation, as has group living itself. It is clear that primates, like other animals, have evolved ways to minimize their risk of predation. However, the extent to which they have been able to do so, given other constraints of living such as their own need to acquire food, has not yet been resolved. Perhaps most hotly debated is whether predation has been the primary selective force favoring the evolution of group living in primates. Part of the difficulty in resolving the debate lies in a paucity of direct evidence of predation. This is regrettable yet understandable since primatologists, by definition, focus on the study of primates, not predators of primates (unless these are also primates). Systematic direct evidence of the effects of predation can best be obtained by studying predators that are as habituated to observers as are their primate prey. Until this is done, we must continue to rely on opportunistic accounts of predation and predation attempts, and on systematically obtained indirect evidence. Such data reveal several interesting patterns: (1) although smaller primates may have greater predation rates than larger primates, even the largest primates are not invulnerable to predation; (2) the use by primates of unfamiliar areas can result in higher predation rates, which might be one pressure favoring philopatry, or site fidelity; (3) arboreal primates are at greater risk of predation when they are more exposed (at forest edges and tops of canopies) than in more concealed locations; (4) predation by mammalian carnivores may often be episodic; and (5) terrestrial primates may not experience greater predation than arboreal primates.     

The interaction of the Escherichia coli mutD and mutT pathways in the prevention of A:T-->C:G transversions.

The Escherichia coli mutT mutator allele produces high frequencies of exclusively A:T-->C:G transversions. This is thought to be caused by a failure to prevent or remove A:G mispairs during DNA replication. The mutD5 mutator allele maps to the dnaQ locus which encodes the epsilon subunit of the DNA polymerase III holoenzyme. This subunit provides 3'-->5' exonuclease, proofreading, activity for removing mispaired nucleotides at the 3' end of the newly synthesized DNA strand. mutD5 has an altered epsilon resulting in reduced levels of proofreading and subsequent high mutation frequencies for all base-pair substitutions. We have analyzed the interaction between mutD5 and mutT-induced A:T-->C:G transversions by measuring reversion frequencies in mutD5 and mutT single mutator strains and mutD5mutT double mutator strains using the well-characterized trpA58 and trpA88 alleles. We find that the double mutator strains produce more A:T-->C:G substitutions than would be expected from simple additivity of the single mutator strains. We interpret this to mean that the two systems, at least in part, do act together to prevent the same mutational intermediate from producing A:T-->C:G transversions. It is estimated that over 90% of the mutT-induced A:G mispairs are corrected by proofreading at the trpA58 site while only about 30% are corrected at trpA88. Reversion frequencies in the mutD5mutT double mutator strains indicate A:G misincorporations occur about 100 x more frequently at trpA58 than at the trpA88 site. Using these and other data we also provide estimations of the fidelity contributions for mutT editing, proofreading and methyl-directed mismatch repair at the two trpA sites for both transversions and the transition that could be scored. In the case of A:T-->C:G transversions, both mutT editing and proofreading make major contributions in error reduction with mismatch repair playing a small or no role at all. For the A:T-->G:C transition, proofreading and mismatch repair were both important in preventing mutations while no contribution was observed for mutT editing.     

Production of 10(S)-hydroxy-8(E)-octadecenoic and 7,10(S,S)-hydroxy-8(E)-octadecenoic ethyl esters by Novozym 435 in solvent-free media

Novozym 435, lipase B from Candida antarctica, was used in this study for the production of ethyl esters. For the first time, trans-hydroxy-fatty acid ethyl esters were synthesized in vitro in solvent-free media. We studied the effects of the substrate–ethanol molar ratio and enzyme synthetic stability of the biocatalyst. To determine the structure of the formed compounds, Fourier transformed infrared spectroscopy, nuclear magnetic resonance, and matrix-assisted laser desorption/ionization–time-of-flight mass spectrometry were used, three less time-consuming structural techniques. trans-Hydroxy-fatty acid ethyl esters were synthesized with a reaction yield of 90 % or higher with optimal reaction conditions.     

能化态线粒体内膜脂流动性与能量偶联活性

本文从观察温度的影响出发,探讨了鼠肝线粒体内膜体,在琥珀酸氧化建立跨膜质子电化学梯度（ΔμＨ＾＋）时,膜脂双分子层中ＤＰＨ荧光偏振值（ｒ）的变化与膜能量偶联活性之间的相互关系。结果表明,１５￣３５℃温度内,能化引起ｒ值变化趋势相似,ｒ值变化速率随温度升高而增加,但与温度对ｒ值影响相比只是在较小的范围内变动。另一方面,１５￣３０℃温度内,随温度升高质子回漏速率加快,ＲＣＲ值和ＡＤＰ／Ｏ比值下降,但跨     

Human impacts on minimum subsets of species critical for maintaining ecosystem structure

Humans have indirectly influenced species at lower trophic levels by driving losses of apex consumers. Furthermore, humans have indirectly influenced species at higher trophic levels by driving losses of primary producers. Beyond these broad classes of apex consumers and primary producers, it remains challenging to identify minimum subsets of species that are particularly important for maintaining ecosystem structure and functioning. Here we use a novel method at the intersection of control theory and network theory to identify a minimum set of driver node species upon which ecosystem structure strongly depends. Specifically, humans could unintentionally completely restructure ecosystems (i.e., change species abundances from any initial values to any final values, including zero) by altering the abundances of these few critical driver node species. We then quantify the proportion of these driver nodes that are influenced by humans, top predators, and primary producers in several marine food webs. We find that humans could unintentionally completely restructure marine food webs while only directly influencing less than one in four species. Additionally, humans directly influence: (1) most or all of the species necessary to completely restructure each network, (2) more driver nodes than top predators, and at least as many driver nodes as primary producers, and (3) an increasing proportion of driver nodes over time in the Adriatic Sea. We conclude that humans have potentially huge impacts on marine ecosystems while directly influencing only the relatively small subset of species that are currently fished. It may be possible to reduce unintentional and undesirable cascading human influences by decreasing human impacts on driver node species in these and other food webs.     

The biodiversity‐dependent ecosystem service debt

Habitat destruction is driving biodiversity loss in remaining ecosystems, and ecosystem functioning and services often directly depend on biodiversity. Thus, biodiversity loss is likely creating an ecosystem service debt: a gradual loss of biodiversity‐dependent benefits that people obtain from remaining fragments of natural ecosystems. Here, we develop an approach for quantifying ecosystem service debts, and illustrate its use to estimate how one anthropogenic driver, habitat destruction, could indirectly diminish one ecosystem service, carbon storage, by creating an extinction debt. We estimate that c. 2–21 Pg C could be gradually emitted globally in remaining ecosystem fragments because of plant species loss caused by nearby habitat destruction. The wide range for this estimate reflects substantial uncertainties in how many plant species will be lost, how much species loss will impact ecosystem functioning and whether plant species loss will decrease soil carbon. Our exploratory analysis suggests that biodiversity‐dependent ecosystem service debts can be globally substantial, even when locally small, if they occur diffusely across vast areas of remaining ecosystems. There is substantial value in conserving not only the quantity (area), but also the quality (biodiversity) of natural ecosystems for the sustainable provision of ecosystem services.     

Changes in ranging and agonistic behavior of vervet monkeys (Cercopithecus aethiops) after predator‐induced group fusion

Socio‐ecological theory predicts that group fusion in female‐philopatric primate species will be rare because females experience increased costs by associating with non‐relatives. Indeed, fusion has been reported only 14 times in only 4 female‐philopatric cercopithecines despite many years of observation. Here, we describe changes in ranging and agonistic behavior of vervet monkeys (Cercopithecus aethiops) after the fusion of two groups, the sole group fusion during 11 years of observation, induced by a brief but intense period of apparent leopard predation. Before fusion, both groups made few incursions into the other group's territory and spent most of the time in their own territories. After the fusion, the amalgamated group shifted its activities and used both territories in similar proportion. Rates of female agonism increased after fusion, particularly in the 2 weeks following fusion, and the small group females assumed the lowest ranks in the female dominance hierarchy. Rates of agonism returned to prefusion rates a month later. Although rates of high‐intensity interactions (i.e., chases) did not increase after fusion, small group females were more likely to be the recipients of, and lose, agonistic interactions than large group females; a small group female and her infant were attacked and wounded by a coalition of large group females shortly after the fusion. The observations presented here reveal that the circumstances surrounding group fusions are more variable than previously realized, but are still in accordance with expectations from socio‐ecological theory that predation can favor the formation of larger groups. In this case, under threat of severe predation, individuals may have surrendered group autonomy for the greater security of larger numbers. Am. J. Primatol. 72:634–644, 2010. © 2010 Wiley‐Liss, Inc.     

Differences Between Vervets (Cercopithecus aethiops) and Patas Monkeys (Erythrocebus patas) in Agonistic Interactions Between Adult Females

We examined agonistic interactions between adult females in wild, unprovisioned patas monkeys (Erythrocebus patas) and vervets (Cercopithecus aethiops). The dominance hierarchy of patas is far less clear than that of vervets. Patas had fewer interactions per dyad, fewer dyads with interactions, and a high percentage (18%) of reversals in which lower-ranking females won in agonistic interactions with higher-ranking females. Although the rank ordering of the kinds of interactions patas and vervets displayed is similar, with avoidance being the most frequently observed agonistic response to approaches by other females, patas were chased and supplanted more often than vervets were. The resources over which females were supplanted also differ between species. Supplants over food comprise smaller proportion of total supplants patas than for vervets. Patas appear to feed on less usurpable foods than vervets. We conclude that (1) Erythrocebus and Cercopithecus spp., except C. aethiops, should not be categorized with other Cercopithecinae, and C. aethiops should not be categorized with other Cercopithecus spp. and Erythrocebus, in discussions and analyses of relationships between females within groups and (2) ecological conditions, i.e., usurpability of foods, can override phylogenetic history as the selective pressure determining the nature of female competitive relationships within groups.     

Biodiversity maintenance mechanisms differ between native and novel exotic-dominated communities

In many systems, native communities are being replaced by novel exotic-dominated ones. We experimentally compared species diversity decline between nine-species grassland communities under field conditions to test whether diversity maintenance mechanisms differed between communities containing all exotic or all native species using a pool of 40 species. Aboveground biomass was greater in exotic than native plots, and this difference was larger in mixtures than in monocultures. Species diversity declined more in exotic than native communities and declines were explained by different mechanisms. In exotic communities, overyielding species had high biomass in monoculture and diversity declined linearly as this selection effect increased. In native communities, however, overyielding species had low biomass in monoculture and there was no relationship between the selection effect and diversity decline. This suggests that, for this system, yielding behaviour is fundamentally different between presumably co-evolved natives and coevolutionarily naive exotic species, and that native-exotic status is important to consider.     

Functional mimicry of the LDL receptor-associated protein through multimerization of a minimized third domain

The LDL receptor-associated protein (RAP) is a ligand for the LDL receptor-related protein (LRP1). The first and third domains of RAP can each bind to one of many sequence-related pairs of complement-type repeats (CR) found within the LRP1 ectodomain. Multiple sites of interaction between the multivalent RAP ligand and the multivalent LRP1 receptor yield strong binding avidity for the complex. The third domain of RAP can be significantly truncated, with material retention of monovalent CR pair-binding affinity, provided that the minimized sequence is stabilized with an intramolecular disulfide bond. We demonstrate that the avidity of full-length RAP for LRP1 in vitro can be partially reconstituted by assembly of truncated, disulfide-linked RAP peptides on tetravalent streptavidin or bivalent immunoglobulin scaffolds. The peptide complex with streptavidin shows pronounced hepatotropism in vivo, replicating the biodistribution of full-length RAP.