Search results for "Life history traits"
showing 10 items of 35 documents
An experimental heat wave changes immune defense and life history traits in a freshwater snail
2013
The predicted increase in frequency and severity of heat waves due to climate change is expected to alter disease dynamics by reducing hosts' ability to resist infections. This could take place via two different mechanisms: (1) through general reduction in hosts' performance under harsh environmental conditions and/or (2) through altered resource allocation that reduces expression of defense traits in order to maintain other traits. We tested these alternative hypotheses by measuring the effect of an experimental heat wave (25 vs. 15°C) on the constitutive level of immune defense (hemocyte concentration, phenoloxidase [PO]‐like activity, antibacterial activity of hemolymph), and life histor…
Plastic and micro-evolutionary responses of a nematode to the host immune environment
2017
9 pages; International audience; Parasitic organisms have to cope with the defences deployed by their hosts and this can be achieved adopting immune evasion strategies or optimal life history traits according to the prevailing pattern of immune-mediated mortality. Parasites often encounter variable immune environments both within and between hosts, promoting the evolution of plastic strategies instead of fixed responses. Here, we explored the plasticity and micro-evolutionary responses of immunomodulatory mechanisms and life history traits to the immune environment provided by the host, using the parasitic nematode Heligmosomoides polygyrus. To test if the parasite responds plastically to t…
Microevolutionary response of a gut nematode to intestinal inflammation.
2017
7 pages; International audience; Parasitic helminths interfere with the immune response of their hosts to establish long-lasting, chronic infections. While favorable to the parasite, the capacity to dampen the immune response can also provide a benefit to the host in terms of reduced risk of immune disorders and immunopathology. The immunomodulatory role of nematodes has been exploited in clinical trials to treat a number of inflammatory and immune diseases. However, how parasites adapt to an inflammatory environment remains a poorly explored question. Here, we conducted a serial passage experiment where the gut nematode Heligmosomoides polygyrus was maintained for nine generations in mice …
Disentangling the effect of host genetics and gut microbiota on resistance to an intestinal parasite
2019
11 pages; International audience; Resistance to infection is a multifactorial trait, and recent work has suggested that the gut microbiota can also contribute to resistance. Here, we performed a fecal microbiota transplant to disentangle the contribution of the gut microbiota and host genetics as drivers of resistance to the intestinal nematode Heligmosomoides polygyrus. We transplanted the microbiota of a strain of mice (SJL), resistant to H. polygyrus, into a susceptible strain (CBA) and vice-versa. We predicted that if the microbiota shapes resistance to H. polygyrus, the FMT should reverse the pattern of resistance between the two host strains. The two host strains had different microbi…
Towards a Unified Functional Trait Framework for Parasites
2019
Trait-based research holds high potential to unveil ecological and evolutionary processes. Functional traits are fitness-related characteristics of individuals, which are measured at individual level and defined without using information external to the individual. Despite the usefulness of the functional approach to understand the performance of individuals in ecosystems, and parasitism being the most common life-history strategy on Earth, studies based on functional traits of parasites are still scarce. Since the choice of functional traits is a critical step for any study, we propose a core list of seven functional traits of metazoan parasites, related to three universal challenges faced…
Life history adjustments to intestinal inflammation in a gut nematode.
2017
ABSTRACT Many parasitic nematodes establish chronic infections. This implies a finely tuned interaction with the host immune response in order to avoid infection clearance. Although a number of immune interference mechanisms have been described in nematodes, how parasites adapt to the immune environment provided by their hosts remains largely unexplored. Here, we used the gastrointestinal nematode Heligmosomoides polygyrus to investigate the plasticity of life history traits and immunomodulatory mechanisms in response to intestinal inflammation. We adopted an experimental model of induced colitis and exposed worms to intestinal inflammation at two different developmental stages (larvae and …
Evidence for a conserved queen-worker genetic toolkit across slave-making ants and their ant hosts
2021
AbstractThe ecological success of social Hymenoptera (ants, bees, wasps) depends on the division of labour between the queen and workers. Each caste is highly specialised in its respective function in morphology, behaviour and life-history traits, such as lifespan and fecundity. Despite strong defences against alien intruders, insect societies are vulnerable to social parasites, such as workerless inquilines or slave-making (dulotic) ants. Here, we investigate whether gene expression varies in parallel ways between lifestyles (slave-making versus host ants) across five independent origins of ant slavery in the “Formicoxenus-group” of the ant tribe Crematogastrini. As caste differences are o…
Effect of river restoration on life-history strategies in fish communities
2019
Assessments of river restoration outcomes are mostly based on taxonomic identities of species, which may not be optimal because a direct relationship to river functions remains obscure and results are hardly comparable across biogeographic borders. The use of ecological species trait information instead of taxonomic units may help to overcome these challenges. Abundance data for fish communities were gathered from 134 river restoration projects conducted in Switzerland, Germany and Finland, monitored for up to 15 years. These data were related to a dataset of 22 categories of ecological traits describing fish life-history strategies to assess the outcome of the restoration projects. Restora…
Ocean acidification and elevated temperature negatively affect recruitment, oxygen consumption and calcification of the reef-building Dendropoma cris…
2019
Expected temperature rise and seawater pH decrease may affect marine organism fitness. By a transplant experiment involving air-temperature manipulation along a natural CO2 gradient, we investigated the effects of high pCO(2) (similar to 1100 mu atm) and elevated temperature (up to +2 degrees C than ambient conditions) on the reproductive success, recruitment, growth, shell chemical composition and oxygen consumption of the early life stages of the intertidal reef-building vermetid Dendropoma cristatum. Reproductive success was predominantly affected by temperature increase, with encapsulated embryos exhibiting higher survival in control than elevated temperature conditions, which were in t…
Costs and benefits of inflammation in host-parasite relationships
2016
Host-parasite interactions are characterized by trade-offs that involve both plastic and microevolutionary responses. On one hand, while immunity is essential to fight parasites, it can also cause damage to the host, leading to autoimmunity and inflammatory diseases. On the other hand, parasites have to cope with the immune environnement provided by the host. This raises the question of the costs and benefits of the inflammatory response for the two partners of the interaction. With different experimental and literature-based approaches, I showed that immunopathology is a trait that likely persists because of the immediate benefits of the immune response in terms of protection against paras…