Microbial transmission in animal social networks and the social microbiome.

Host-associated microbiomes play an increasingly appreciated role in animal metabolism, immunity and health. The microbes in turn depend on their host for resources and can be transmitted across the host's social network. In this Perspective, we describe how animal social interactions and networks may provide channels for microbial transmission.

Taking note of Tinbergen, or: the promise of a biology of behaviour.

In this concluding paper, we revisit Tinbergen's 1963 article and assess its impact on the field of behavioural research in general, and the papers in this volume in particular. We show how Tinbergen's insistence that greater attention should be paid to studies of 'survival value' has yielded immense returns over the past 50 years, allowing an integrative biology of behaviour to emerge and thrive, and that his addition of ontogeny to the 'major problems of biology' was both insightful and prescient.

Evidence for a genetic basis of aging in two wild vertebrate populations.

Aging, or senescence, defined as a decline in physiological function with age, has long been a focus of research interest for evolutionary biologists. How has natural selection failed to remove genetic effects responsible for such reduced fitness among older individuals? Current evolutionary theory explains this phenomenon by showing that, as a result of the risk of death from environmental causes that individuals experience, the force of selection inevitably weakens with age. This in turn means that genetic mutations having detrimental effects that are only felt late in life might persist in a population.

Developmental plasticity and human health.

Many plants and animals are capable of developing in a variety of ways, forming characteristics that are well adapted to the environments in which they are likely to live. In adverse circumstances, for example, small size and slow metabolism can facilitate survival, whereas larger size and more rapid metabolism have advantages for reproductive success when resources are more abundant. Often these characteristics are induced in early life or are even set by cues to which their parents or grandparents were exposed.