Parasitism and constitutive defence costs to host life-history traits in a parasitoid-host interaction

Animals and plants host diverse communities of microorganisms, and these microbiotas have been shown to influence host life history traits. Much has been said about the benefits that host-associated microbiotas bestow on the host. However, life history traits often demonstrate tradeoffs among one another. Raising Caenorhabditis elegans nematodes in compost microcosms emulating their natural environment, we examined how complex microbiotas affect host life history traits. We show that soil microbes usually increase the host development rate but decrease host resistance to heat stress, suggesting that interactions with complex microbiotas may mediate a tradeoff between host development and stress resistance. What element in these interactions is responsible for these effects is yet unknown, but experiments with live versus dead bacteria suggest that such effects may depend on bacterially provided signals.

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Coevolutionary interactions between host life histories and parasite life cycles

Parasitology ◽

10.1017/s0031182000084936 ◽

1998 ◽

Vol 116 (S1) ◽

pp. S47-S55 ◽

Cited By ~ 26

Author(s):

J. C. Koella ◽

P. Agnew ◽

Y. Michalakis

Keyword(s):

Life History ◽

Life Cycle ◽

Life Histories ◽

Life History Traits ◽

Evolutionary Ecology ◽

Life Cycles ◽

Microsporidian Parasite ◽

History Of ◽

Host Life ◽

Host Parasite

SummarySeveral recent studies have discussed the interaction of host life-history traits and parasite life cycles. It has been observed that the life-history of a host often changes after infection by a parasite. In some cases, changes of host life-history traits reduce the costs of parasitism and can be interpreted as a form of resistance against the parasite. In other cases, changes of host life-history traits increase the parasite's transmission and can be interpreted as manipulation by the parasite. Alternatively, changes of host's life-history traits can also induce responses in the parasite's life cycle traits. After a brief review of recent studies, we treat in more detail the interaction between the microsporidian parasite Edhazardia aedis and its host, the mosquito Aedes aegypti. We consider the interactions between the host's life-history and parasite's life cycle that help shape the evolutionary ecology of their relationship. In particular, these interactions determine whether the parasite is benign and transmits vertically or is virulent and transmits horizontally.Key words: host-parasite interaction, life-history, life cycle, coevolution.

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Optimal immune specificity at the intersection of host life history and parasite epidemiology

PLoS Computational Biology ◽

10.1371/journal.pcbi.1009714 ◽

2021 ◽

Vol 17 (12) ◽

pp. e1009714

Author(s):

Alexander E. Downie ◽

Andreas Mayer ◽

C. Jessica E. Metcalf ◽

Andrea L. Graham

Keyword(s):

Life History ◽

Life History Traits ◽

Reproductive Maturity ◽

Structured Population ◽

Specificity And Sensitivity ◽

Population Dynamics Model ◽

Structured Population Dynamics ◽

Host Life ◽

The Relationship ◽

Shed Light

Hosts diverge widely in how, and how well, they defend themselves against infection and immunopathology. Why are hosts so heterogeneous? Both epidemiology and life history are commonly hypothesized to influence host immune strategy, but the relationship between immune strategy and each factor has commonly been investigated in isolation. Here, we show that interactions between life history and epidemiology are crucial for determining optimal immune specificity and sensitivity. We propose a demographically-structured population dynamics model, in which we explore sensitivity and specificity of immune responses when epidemiological risks vary with age. We find that variation in life history traits associated with both reproduction and longevity alters optimal immune strategies–but the magnitude and sometimes even direction of these effects depends on how epidemiological risks vary across life. An especially compelling example that explains previously-puzzling empirical observations is that depending on whether infection risk declines or rises at reproductive maturity, later reproductive maturity can select for either greater or lower immune specificity, potentially illustrating why studies of lifespan and immune variation across taxa have been inconclusive. Thus, the sign of selection on the life history-immune specificity relationship can be reversed in different epidemiological contexts. Drawing on published life history data from a variety of chordate taxa, we generate testable predictions for this facet of the optimal immune strategy. Our results shed light on the causes of the heterogeneity found in immune defenses both within and among species and the ultimate variability of the relationship between life history and immune specificity.

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Coevolution between Parasite Virulence and Host Life-History Traits

The American Naturalist ◽

10.2307/3079283 ◽

2002 ◽

Vol 160 (3) ◽

pp. 374

Author(s):

Gandon ◽

Agnew ◽

Michalakis

Keyword(s):

Life History ◽

Life History Traits ◽

Host Life

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Evolutionary implications of host–pathogen specificity: the fitness consequences of host life history traits

Evolutionary Ecology ◽

10.1023/a:1011647526731 ◽

2000 ◽

Vol 14 (8) ◽

pp. 665-692 ◽

Cited By ~ 13

Author(s):

J.W. Kirchner ◽

B.A. Roy

Keyword(s):

Life History ◽

Life History Traits ◽

Fitness Consequences ◽

Host Pathogen ◽

Host Life

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Parasitic effects on host life-history traits : a review of recent studies

Parasite ◽

10.1051/parasite/1994014291 ◽

1994 ◽

Vol 1 (4) ◽

pp. 291-294 ◽

Cited By ~ 63

Author(s):

Y. Michalakis ◽

M. E. Hochberg

Keyword(s):

Life History ◽

Life History Traits ◽

Parasitic Effects ◽

Host Life

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Resource depletion in Aedes aegypti mosquitoes infected by the microsporidia Vavraia culicis

Parasitology ◽

10.1017/s0031182007002703 ◽

2007 ◽

Vol 134 (10) ◽

pp. 1355-1362 ◽

Cited By ~ 31

Author(s):

A. RIVERO ◽

P. AGNEW ◽

S. BEDHOMME ◽

C. SIDOBRE ◽

Y. MICHALAKIS

Keyword(s):

Life History ◽

Aedes Aegypti ◽

Life History Traits ◽

Feeding Rate ◽

Parasitic Infection ◽

Resource Depletion ◽

Mosquito Larvae ◽

Microsporidian Parasite ◽

Host Life ◽

Host Development

SUMMARYParasitic infection is often associated with changes in host life-history traits, such as host development. Many of these life-history changes are ultimately thought to be the result of a depletion or reallocation of the host's resources driven either by the host (to minimize the effects of infection) or by the parasite (to maximize its growth rate). In this paper we investigate the energetic budget of Aedes aegypti mosquito larvae infected by Vavraia culicis, a microsporidian parasite that transmits horizontally between larvae, and which has been previously shown to reduce the probability of pupation of its host. Our results show that infected larvae have significantly less lipids, sugars and glycogen than uninfected larvae. These differences in resources were not due to differences in larval energy intake (feeding rate) or expenditure (metabolic rate). We conclude that the lower energetic resources of infected mosquitoes are the result of the high metabolic demands that microsporidian parasites impose on their hosts. Given the fitness advantages for the parasite of maintaining the host in a larval stage, we discuss whether resource depletion may also be a parasite mechanism to prevent the pupation of the larvae and thus maximize its own transmission.

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