Population dynamics

  • Letter |

    Assessment of the impact of armed conflict on large herbivores in Africa between 1946 and 2010 reveals that high conflict frequency is an important predictor of wildlife population declines.

    • Joshua H. Daskin
    •  & Robert M. Pringle
  • Letter |

    Analysis of three wild-caught bumblebee species shows that family lineage survival and persistence is significantly increased between successive colony cycle stages with the proportion of high-value foraging habitat near the natal colony.

    • Claire Carvell
    • , Andrew F. G. Bourke
    •  & Matthew S. Heard
  • Letter |

    Demographic analysis of life expectancy and maximum reported age at death provides evidence that human lifespan has reached its natural limit.

    • Xiao Dong
    • , Brandon Milholland
    •  & Jan Vijg
  • Letter |

    Whole-genome sequencing of individuals from 125 populations provides insight into patterns of genetic diversity, natural selection and human demographic history during the peopling of Eurasia and finds evidence for genetic vestiges of an early expansion of modern humans out of Africa in Papuans.

    • Luca Pagani
    • , Daniel John Lawson
    •  & Mait Metspalu
  • Letter |

    Clinically relevant bacteria have been engineered to lyse synchronously at a threshold population density and release genetically encoded therapeutics; treatment of mice with these bacteria slowed the growth of tumours.

    • M. Omar Din
    • , Tal Danino
    •  & Jeff Hasty
  • Letter |

    South America was the last habitable continent to be colonized by humans; using a database of 1,147 archaeological sites and 5,464 radiocarbon dates spanning 14,000 to 2,000 years ago reveals two phases of the population history of the continent—a rapid expansion through the continent at low population sizes for over 8,000 years and then a second phase of sedentary lifestyle and exponential population growth starting around 5,000 years ago.

    • Amy Goldberg
    • , Alexis M. Mychajliw
    •  & Elizabeth A. Hadly
  • Letter |

    The Trivers–Willard theory proposing that maternal condition influences offspring sex ratio is extended by analysing how differences in mortality rates, age‐specific reproduction and life history tactics between males and females may affect adaptive offspring sex ratio adjustment in two systems.

    • Susanne Schindler
    • , Jean‐Michel Gaillard
    •  & Tim Coulson
  • Letter |

    The capacity of Amazonian forests to sequester carbon has weakened with potentially important implications for climate change.

    • R. J. W. Brienen
    • , O. L. Phillips
    •  & R. J. Zagt
  • Letter |

    Here, colonies of social spiders are used to investigate the evolution of a group-level trait, the ratio of individuals with the ‘docile’ versus ‘aggressive’ phenotype in a colony; experimental colonies were generated with varying ratios and established in the wild, revealing group-level selection.

    • Jonathan N. Pruitt
    •  & Charles J. Goodnight
  • Letter |

    Bovine tuberculosis is a major economic burden on the cattle industry, and attempts to control it have been politically controversial; here farm movement and bovine tuberculosis incidence data are used to construct a mechanistic model and tease apart the factors contributing to epidemic bovine tuberculosis spread.

    • Ellen Brooks-Pollock
    • , Gareth O. Roberts
    •  & Matt J. Keeling
  • Letter |

    Much of what we know about the behaviour of animals in the wild comes from studies in which individual animals are marked for identification purposes. But can the marking itself affect the outcome? This study shows that it does. In a ten-year study on king penguins in the Antarctic, penguins sporting identification bands on their wings had significantly lower long-term fitness than unmarked penguins. This study should give pause for thought to researchers seeking to discover the behaviour of animals in the wild.

    • Claire Saraux
    • , Céline Le Bohec
    •  & Yvon Le Maho
  • Letter |

    Climate change is expected to shift the latitudinal and altitudinal ranges of species, but the low latitude or low altitude edge does not necessarily move as fast as the high edge. Here, demographic data on two tundra plants have been used to show that changed demographic rates at the lower edge are compensating for the warming climate, but that this effect will not last and a tipping point will be reached as temperatures get warmer.

    • Daniel F. Doak
    •  & William F. Morris
  • Letter |

    Populations that become extinct because of environmental degradation pass a tipping point, after which extinction is inevitable. But theory predicts that the population's dynamics indicate what is coming beforehand, through the phenomenon of critical slowing down. It has now been shown that critical slowing down can be used to anticipate extinction in experimental populations of Daphnia magna.

    • John M. Drake
    •  & Blaine D. Griffen
  • Letter |

    Bacteria regularly evolve antibiotic resistance, but little is known about this process at the population level. Here, a continuous culture of Escherichia coli facing increasing antibiotic levels is followed. Most isolates taken from this population are less antibiotic resistant than the population as a whole. A few highly resistant mutants provide protection to the less resistant constituents, in part by producing the signalling molecule indole, which serves to turn on drug efflux pumps and oxidative-stress protective mechanisms.

    • Henry H. Lee
    • , Michael N. Molla
    •  & James J. Collins
  • Letter |

    Climate change can affect the phenology, population dynamics and morphology of species, but it is difficult to study all these factors and their interactions at once. Using long-term data for individual yellow-bellied marmots, these authors show that climate change has increased the length of the marmot growing season, leading to a gradual increase in individual size. It has simultaneously increased the fitness of large individuals, leading to a rapid increase in population size.

    • Arpat Ozgul
    • , Dylan Z. Childs
    •  & Tim Coulson