Introduction. Ecological immunology

Zoological Institute, University of Kiel, Am Botanischen Garten, 24098 Kiel, Germany.
Philosophical Transactions of The Royal Society B Biological Sciences (Impact Factor: 7.06). 11/2008; 364(1513):3-14. DOI: 10.1098/rstb.2008.0249
Source: PubMed


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.

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Available from: Yannick Moret, Nov 24, 2014
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    • "A key assumption in ecological immunology is that immunity is a costly trait in energetic terms (Schmid-Hempel 2003, 2005, Schulenburg et al 2009, Moreno-García et al 2013). This assumption relies on the premise that immunity is condition-dependent so that only individuals in good condition are able to mount an efficient immune response and afford its costs (Schmid-Hempel 2003, 2005). "
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    ABSTRACT: Ecological immunology assumes that the host immune efficiency is correlated with its survival after pathogen challenge. To test this hypothesis, we challenged Phyllophaga polyphylla (Bates) larvae with the naturally occurring fungus Metarhizium pingshaense on two consecutive years (2011 and 2012). In each year, we injected the blastospores of M. pingshaense and then used levels of prophenoloxidase (proPO), phenoloxidase (PO) and total haemolymph serum protein as indicators of immune efficiency. Larvae were injected with (1) phosphate buffered saline (PBS) + Tween and viable blastospores of M. pingshaense, (2) PBS + Tween and non-viable blastospores of M. pingshaense, (3) PBS + Tween, or (4) non-manipulated. Overall, levels of PO, proPO and total haemolymph serum protein in larvae after 12 h were similar amongst treatments within each year of collection. However, larvae collected in 2011 showed higher PO and proPO activity but lower total haemolymph serum protein compared with larvae collected in 2012. A survival study injecting viable blastospores showed that larvae collected in both years died within 48 h; however, when non-viable blastospores were injected, which were still toxic to larvae, mortality was greater in larvae collected in 2011 compared with larvae collected in 2012. Altogether, these results indicate that PO, proPO and total haemolymph serum protein do not predict immune strength of P. polyphylla against blastospores of M. pingshaense, but higher values of PO and proPO were correlated with higher survival rates against non-infective but toxic agents. The possible role of some abiotic factors over the differences observed for immune components of P. polyphylla in different years of collection is discussed.
    Full-text · Article · Aug 2015 · Neotropical Entomology
    • "If ecological demands are great, or if fitness can be maximized via growth or reproduction, immune defences may be compromised, lowered or altered (Martin et al., 2011). In this sense, hosts are able to fight parasites using two strategies: (1) tolerance decreases or alleviates fitness reduction owing to parasite infection, but without reducing parasite infection or growth (Schulenburg et al., 2009; Baucom and De Roode, 2011); (2) resistance prevents infection or reduces parasite growth by confining parasite spread or investing in immune components that sequester parasites or protect and repair host tissues (Rynkiewicz et al., 2013). The two strategies are not necessarily mutually exclusive within an individual, and, at certain burden thresholds, individuals may switch from a resistance strategy to one of tolerance (Schmid-Hempel, 2011). "
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    ABSTRACT: Immunological studies are often context-independent. But eco-immunology is emerging as an alternative, focusing on the natural variation of immune functions of free-living organisms in relation to their ecological constraints and evolutionary context. Immunological studies also tend to study only parasite resistance, that is, mechanisms by which hosts prevent infection or reduce parasite growth. But eco immunology deals with tolerance as well as resistance. Through tolerance, hosts defend themselves by minimizing the damage caused by parasites instead of reducing parasite infection.
    No preview · Article · Jul 2015 · Evolutionary ecology research
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    • "To assess the adaptive value and context dependence of a paternal effect experimentally, it is necessary to manipulate exactly the same selective pressure in both parental and offspring generations. To this end, experimental exposure to parasites is ideal, given: (1) their ubiquitous presence in nature (Moore 2002) (2) their known fluctuating dynamics (Decaestecker et al. 2007) and (3) their detrimental effects on host condition and reproductive success (Kalbe et al. 2009; Schulenburg & Kurtz 2009). Genes responding to parasitemediated selection increase immunological resistance against the parasite and reduce the likelihood of infection (Sorci et al. 1997; Eizaguirre & Lenz 2010; Eizaguirre et al. 2012). "
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    ABSTRACT: Forces shaping an individual's phenotype are complex and include transgenerational effects. Despite low investment into reproduction, a father's environment and phenotype can shape its offspring's phenotype. Whether and when such paternal effects are adaptive, however, remains elusive. Using three-spined sticklebacks in controlled infection experiments, we show that sperm deficiencies in exposed males compared to their unexposed brothers functionally translated into reduced reproductive success in sperm competition trials. In non-competitive fertilisations, off-spring of exposed males suffered significant costs of reduced hatching success and survival but they reached a higher body condition than their counterparts from unexposed fathers after experi-mental infection. Interestingly, those benefits of paternal infection did not result from increased resistance but from increased tolerance to the parasite. Altogether, these results demonstrate that parasite resistance and tolerance are shaped by processes involving both genetic and non-genetic inheritance and suggest a context-dependent adaptive value of paternal effects. Keywords Host–parasite interaction, in vitro fertilisation, paternal effects, sperm phenotype, three-spined stickleback. Ecology Letters (2014) INTRODUCTION
    Full-text · Article · Nov 2014 · Ecology Letters
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