Introduction. Ecological immunology

Abstract

An organism's fitness is critically reliant on its immune system to provide protection against parasites and pathogens. The structure of even simple immune systems is surprisingly complex and clearly will have been moulded by the organism's ecology. The aim of this review and the theme issue is to examine the role of different ecological factors on the evolution of immunity. Here, we will provide a general framework of the field by contextualizing the main ecological factors, including interactions with parasites, other types of biotic as well as abiotic interactions, intraspecific selective constraints (life-history trade-offs, sexual selection) and population genetic processes. We then elaborate the resulting immunological consequences such as the diversity of defence mechanisms (e.g. avoidance behaviour, resistance, tolerance), redundancy and protection against immunopathology, life-history integration of the immune response and shared immunity within a community (e.g. social immunity and microbiota-mediated protection). Our review summarizes the concepts of current importance and directs the reader to promising future research avenues that will deepen our understanding of the defence against parasites and pathogens.

Integrating nutrition and immunology: A new frontier

“…The idea that disease resistance is costly and is traded off against other traits, such as reproductive effort and longevity, is fundamental to the field of ecological immunology (e.g. (Lochmiller and Deerenberg, 2000;Owens and Wilson, 1999;Schulenburg et al, 2009;Sheldon and Verhulst, 1996;Wilson, 2005) Norris & Evans 2000; Wilson 2005). In order to test this hypothesis, immune-related costs must be experimentally distinguished from other pathological processes associated with infection.…”

Reduced consumption of protein-rich foods follows immune challenge in a polyphagous caterpillar

“…However, a growing body of empirical work in the field of ecological immunology has shown that immune parameters in insects respond to various ecological factors, and may be induced on time scales relevant to the individual's fitness (Best et al, 2013;Rolff and Siva-Jothy, 2003;Schmid-Hempel, 2003;SchmidHempel, 2005;Schulenburg et al, 2009). …”

Early origins of inflammation: microbial exposures in infancy predict lower levels of C-reactive protein in adulthood

“…An alternative, and not necessarily contradictory, adaptationist approach recognizes that anti-pathogen defences are energetically costly to the organism, and that systems of defence can be expected to develop in response to ecological factors across the life course (Sheldon & Verhulst 1996;Schulenburg et al 2009). CRP is an important component of innate immunity, and is involved in activating complement, promoting phagocytic activity and opsonizing bacteria, fungi and parasites.…”