Evolutionary Parasitology

Abstract

Parasites are ubiquitous and shape almost every aspect of their hosts, including physiology, behaviour, life histories, the structure of the microbiota, and entire communities. Hence, parasitism is one of the most potent forces in nature and, without parasites, the world would look very different. The book gives an overview over the parasite groups and the diversity of defences that hosts have evolved, such as immune systems. Principles of evolutionary biology and ecology analyse major elements of host–parasite interactions, including virulence, infection processes, tolerance, resistance, specificity, memory, polymorphisms, within-host dynamics, diseases spaces, and many other aspects. Genetics is always one of the key elements in these topics. Modelling, furthermore, can predict best strategies for host and parasites. Similarly, the spread of an infectious disease in epidemiology combines with molecular data and genomics. Furthermore, parasites have evolved ways to overcome defences and to manipulate their hosts. Hosts and parasites, therefore, continuously co-evolve, with changes sometimes occurring very rapidly, and sometimes requiring geological times. Many infectious diseases of humans have emerged from a zoonotic origin, in processes governed by the basic principles discussed in the different sections. Hence, this book integrates different fields to study the diversity of host–parasite processes and phenomena. It summarizes the essential topics for the study of evolutionary parasitology and will be useful for a broad audience.

The hidden costs of resistance: Contrasting the energetics of successfully and unsuccessfully fighting infection

“…When encountering a pathogen, a host is expected to first focus on killing a pathogen early during infection before turning to controlling the growth of the newly established pathogen or repairing any subsequent damage (Hall et al., 2017; Schmid‐Hempel, 2011; Siva‐Jothy et al., 2005). Our findings show that the metabolic trajectory of an exposed host diverges quickly during the infection process as a result and is maintained long after the initial encounter (Figure 1).…”

“…Under the threat of infection, a host is required to activate a costly immune system, sequester essential nutrients away from the invading pathogen and potentially repair damaged tissue (Schmid‐Hempel, 2011; Siva‐Jothy et al., 2005). Exposure to a pathogen is therefore predicted to lead to increased energy use as organisms strive to meet the added energetic demands of fighting infection (Schmid‐Hempel, 2003; Sheldon & Verhulst, 1996).…”

Quick guide to evolutionary medicine in neuroimmunomodulation: Why “evolved for the benefit of the species” is not a valid argument

“…In male mammals, too low testosterone levels inhibit spermatogenesis [83], but high levels of testosterone can have an immunoinhibitory influence, leading to a tradeoff [84]. An outstanding example of this is the unique reproduction of small carnivorous marsupials of the genus Antechinus [85].…”

Ectopical expression of bacterial collagen-like protein supports its role as adhesin in host–parasite coevolution

“…Antagonistic coevolution between hosts and parasites has been suggested to be a major driver in evolution, presumably underlying diverse biological phenomena, such as the extraordinary genetic variation at the major histocompatibility complex of jawed vertebrates and R-genes in plants, the parasite hypothesis about the evolution of sexual selection, the evolution of genetic recombination and the evolution of immune systems [1][2][3]. While great progress has been made in our understanding of coevolution and its consequences at the phenotypic level, much less is known about the underlying genetics [4][5][6].…”