On the evolutionary ecology of host-parasite interactions: addressing the question with regard to bumblebees and their parasites

Although much research in evolutionary ecology is based upon the premise that high levels of parasitism impair the host's functioning, the assumed link between parasitism and fitness has been assessed for relatively few kinds of animals. At our study site in tropical Australia, keelback snakes ( Tropidonophis mairii (Gray, 1841), Colubridae) are heavily infected with haemogregarine blood parasites: 90% of snakes that we tested carried the parasite, with the proportion of erythrocytes containing haemogregarines averaging 15% and ranging up to a remarkable 64%. Prevalence increased with snake body size, but intensity decreased with age. Unlike lizards studied previously, the snakes did not respond to haemogregarine infection by releasing immature erythrocytes into the circulation. In striking contrast to results from a recent study on a sympatric snake species, we did not find any empirical links between parasite numbers and several measures of host fitness (body condition, growth rate, feeding rate, antipredator behaviour, locomotor performance, reproductive status, reproductive output, and recapture rate). The association between this parasite and its host thus appears to be surprisingly benign, suggesting that host–parasite interactions sometimes may have only trivial consequences for host fitness in natural populations. Plausibly, host–parasite coevolution weakens or eliminates fitness costs of parasitism.

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Immune defence, parasite evasion strategies and their relevance for ‘macroscopic phenomena’ such as virulence

Philosophical Transactions of the Royal Society B Biological Sciences ◽

10.1098/rstb.2008.0157 ◽

2008 ◽

Vol 364 (1513) ◽

pp. 85-98 ◽

Cited By ~ 105

Author(s):

Paul Schmid-Hempel

Keyword(s):

Immune Evasion ◽

Life History Theory ◽

Evolutionary Ecology ◽

Parasite Clearance ◽

Multiple Infections ◽

Parasite Fitness ◽

Host Parasite Interactions ◽

Evolution Of Virulence ◽

Host Parasite ◽

Insight Into

The discussion of host–parasite interactions, and of parasite virulence more specifically, has so far, with a few exceptions, not focused much attention on the accumulating evidence that immune evasion by parasites is not only almost universal but also often linked to pathogenesis, i.e. the appearance of virulence. Now, the immune evasion hypothesis offers a deeper insight into the evolution of virulence than previous hypotheses. Sensitivity analysis for parasite fitness and life-history theory shows promise to generate a more general evolutionary theory of virulence by including a major element, immune evasion to prevent parasite clearance from the host. Also, the study of dose–response relationships and multiple infections should be particularly illuminating to understand the evolution of virulence. Taking into account immune evasion brings immunological processes to the core of understanding the evolution of parasite virulence and for a range of related issues such as dose, host specificity or immunopathology. The aim of this review is to highlight the mechanism underlying immune evasion and to discuss possible consequences for the evolutionary ecology analysis of host–parasite interactions.

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The role of the environment in the evolutionary ecology of host parasite interactions

Infection Genetics and Evolution ◽

10.1016/j.meegid.2008.01.011 ◽

2008 ◽

Vol 8 (3) ◽

pp. 302-305 ◽

Cited By ~ 17

Author(s):

Pedro F. Vale ◽

Lucie Salvaudon ◽

Oliver Kaltz ◽

Simon Fellous

Keyword(s):

Evolutionary Ecology ◽

Host Parasite Interactions ◽

Host Parasite

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Host–parasite biology in the real world: the field voles of Kielder

Parasitology ◽

10.1017/s0031182014000171 ◽

2014 ◽

Vol 141 (8) ◽

pp. 997-1017 ◽

Cited By ~ 14

Author(s):

A. K. TURNER ◽

P. M. BELDOMENICO ◽

K. BOWN ◽

S. J. BURTHE ◽

J. A. JACKSON ◽

...

Keyword(s):

Real World ◽

Evolutionary Ecology ◽

The Body ◽

Microtus Agrestis ◽

The Real ◽

Multidisciplinary Study ◽

Host Parasite Interactions ◽

Parasite Biology ◽

Host Parasite ◽

Empirical Approaches

SUMMARYResearch on the interactions between the field voles (Microtus agrestis) of Kielder Forest and their natural parasites dates back to the 1930s. These early studies were primarily concerned with understanding how parasites shape the characteristic cyclic population dynamics of their hosts. However, since the early 2000s, research on the Kielder field voles has expanded considerably and the system has now been utilized for the study of host–parasite biology across many levels, including genetics, evolutionary ecology, immunology and epidemiology. The Kielder field voles therefore represent one of the most intensely and broadly studied natural host–parasite systems, bridging theoretical and empirical approaches to better understand the biology of infectious disease in the real world. This article synthesizes the body of work published on this system and summarizes some important insights and general messages provided by the integrated and multidisciplinary study of host–parasite interactions in the natural environment.

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