Search results for "host"

Food limitation constrains host immune responses to nematode infections.

2016

Trade-offs in the allocation of finite-energy resources among immunological defences and other physiological processes are believed to influence infection risk and disease severity in food-limited wildlife populations. However, this prediction has received little experimental investigation. Here we test the hypothesis that food limitation impairs the ability of wild field voles ( Microtus agrestis ) to mount an immune response against parasite infections. We conducted a replicated experiment on vole populations maintained in large outdoor enclosures during boreal winter, using food supplementation and anthelmintic treatment of intestinal nematodes. Innate immune responses against intestina…

Fitness costs of worker specialization for ant societies

2016

Division of labour is of fundamental importance for the success of societies, yet little is known about how individual specialization affects the fitness of the group as a whole. While specialized workers may be more efficient in the tasks they perform than generalists, they may also lack the flexibility to respond to rapid shifts in task needs. Such rigidity could impose fitness costs when societies face dynamic and unpredictable events, such as an attack by socially parasitic slavemakers. Here, we experimentally assess the colony-level fitness consequences of behavioural specialization in Temnothorax longispinosus ants that are attacked by the slavemaker ant T. americanus . We manipulate…

Phenological and intrinsic predictors of mite and haemacoccidian infection dynamics in a Mediterranean community of lizards

2021

Ectotherms are vulnerable to environmental changes and their parasites are biological health indicators. Thus, parasite load in ectotherms is expected to show a marked phenology. This study investigates temporal host–parasite dynamics in a lizard community in Eastern Spain during an entire annual activity period. The hosts investigated were Acanthodactylus erythrurus, Psammodromus algirus and Psammodromus edwardsianus, three lizard species coexisting in a mixed habitat of forests and dunes, providing a range of body sizes, ecological requirements and life history traits. Habitat and climate were considered as potential environmental predictors of parasite abundance, while size, body conditi…

DNA Taxonomy Confirms the Identity of the Widely-Disjunct Mediterranean and Atlantic Populations of the Tufted Ghost Crab Ocypode cursor (Crustacea: …

2019

The distribution area of the tufted ghost crab Ocypode cursor includes two widely separate sub-areas, i.e. the tropical and subtropical Atlantic coasts of Africa and Macaronesia, and the central-eastern Mediterranean basin. The current disjunct distribution of the species is possibly the remnant of a previous wider and continuous distribution area that was fragmented during the Pleistocene, with the disappearance of the species from the temperate Atlantic Ocean and the western Mediterranean basin, and its survival in the warmer areas of the eastern Atlantic and the Mediterranean Sea. Such disjunction is thus compatible with an ancient isolation between the Mediterranean and Atlantic populat…

Effect of antibiotic treatment and gamma-irradiation on cuticular hydrocarbon profiles and mate choice in tsetse flies (Glossina m. morsitans).

2018

Background Symbiotic microbes represent a driving force of evolutionary innovation by conferring novel ecological traits to their hosts. Many insects are associated with microbial symbionts that contribute to their host’s nutrition, digestion, detoxification, reproduction, immune homeostasis, and defense. In addition, recent studies suggest a microbial involvement in chemical communication and mating behavior, which can ultimately impact reproductive isolation and, hence, speciation. Here we investigated whether a disruption of the microbiota through antibiotic treatment or irradiation affects cuticular hydrocarbon profiles, and possibly mate choice behavior in the tsetse fly, Glossina mors…

2021

Environmental heterogeneity is a central component influencing the virulence and epidemiology of infectious diseases. The number and distribution of susceptible hosts determines disease transmission opportunities, shifting the epidemiological threshold between the spread and fadeout of a disease. Similarly, the presence and diversity of other hosts, pathogens and environmental microbes, may inhibit or accelerate an epidemic. This has important applied implications in farming environments, where high numbers of susceptible hosts are maintained in conditions of minimal environmental heterogeneity. We investigated how the quantity and quality of aquaculture enrichments (few vs. many stones; cl…

Benefits of immune protection versus immunopathology costs: a synthesis from cytokine KO models.

2017

5 pages; International audience; The inflammatory response can produce damage to host tissues and in several infectious diseases the most severe symptoms are due to immunopathology rather than a direct effect of pathogen multiplication. One hypothesis for the persistence of inflammatory damage posits that the benefits of protection towards infection outweigh the costs. We used data on knocked-out (KO) cytokine models [and the corresponding wild-type (WT) controls] to test this hypothesis. We computed differences in pathogen load and host survival between WT and KO and divided them by the WT values. Using this ratio provides an internal control for variation in pathogen species, host strain,…

Nitric oxide: a multitask player in plant–microorganism symbioses

2016

Symbiosis is a close and often long-term interaction between two different biological organisms, i.e. plants or fungi and microorganisms. Two main types of plant–microorganism interactions, mutualistic and cooperative, have been categorized. Mutualistic interactions, including nitrogen-fixing and mycorrhizal symbioses, refer to mostly obligate relationships between a host plant and a symbiont microorganism. Cooperative interactions correspond to less obligate and specific relationships. They involve microorganisms, referred to as plant growth-promoting rhizobia (PGPR), able to colonize root surface or inner tissues. Lichens are symbiotic associations of host fungi and photosynthetic partner…

Evolutionary relationships between digeneans of the family Brachycladiidae Odhner, 1905 and their marine mammal hosts: A cophylogenetic study.

2016

Cophylogenetic studies examine the congruence between host and parasite phylogenies. There are few studies that quantify the relative contribution of coevolutionary events, i.e. duplication, loss, failure-to-diverge, host-switching and spreading in trophically-transmitted parasites at the marine realm. We addressed this issue in the Brachycladiidae, a cosmopolitan digenean family specific to marine mammals. We used, for the first time, distance-based and event-based methods to explicitly test the coevolutionary events that have shaped the current brachycladiid-marine mammal associations. Parasite phylogeny was constructed using mtDNA ND3 sequences of nine brachycladiid species, and host phy…

Responses of marine mussel Mytilus galloprovincialis (Bivalvia: Mytilidae) after infection with the pathogen Vibrio splendidus

2019

International audience; Bivalve molluscs possess effective cellular and humoral defence mechanisms against bacterial infection. Although the immune responses of mussels to challenge with pathogenic vibrios have been largely investigated, the effects at the site of injection at the tissue level have not been so far evaluated. To this aim, mussels Mytilus galloprovincialis were herein in vivo challenged with Vibrio splendidus to assess the responses induced in hemolymph and posterior adductor muscle (PAM), being the site of bacterial infection. The number of living intra-hemocyte bacteria increased after the first hour post-injection (p.i.), suggesting the occurrence of an intense phagocytosi…