Search results for "biodiversity | causal language"
showing 10 items of 881 documents
Females pay the oxidative cost of dominance in a highly social bird.
2018
12 pages; International audience; Understanding the evolution and maintenance of social behaviour requires a better understanding of the physiological mechanisms underlying the trade-offs between the benefits and costs of social status. Social dominance is expected to provide advantages in terms of access to resources and to reproduction but acquiring and maintaining dominance may also entail physiological costs. Dominant individuals are likely to engage more frequently in aggressive behaviours and/or may allocate a substantial amount of energy and resources to signal their status. Hence, dominance is likely to involve multiple physiological processes that stimulate aerobic metabolism and l…
Opportunity costs resulting from scramble competition within the choosy sex severely impair mate choosiness.
2016
12 pages; International audience; Studies on mate choice mainly focus on the evolution of signals that would maximize the probability of finding a good-quality partner. Most models of sexual selection rely on the implicit assumption that individuals can freely compare and spot the best mates in a heterogeneous population. Comparatively few studies have investigated the consequences of the mate-sampling process. Several sampling strategies have been studied from theoretical or experimental perspectives. They belong to two families of decision rules: best-of-n strategies (individuals sample n partners before choosing the best one within this pool) or threshold strategies (individuals sequenti…
First extensive characterization of the venom gland from an egg parasitoid: structure, transcriptome and functional role.
2018
The venom gland is a ubiquitous organ in Hymenoptera. In insect parasitoids, the venom gland has been shown to have multiple functions including regulation of host immune response, host paralysis, host castration and developmental alteration. However, the role played by the venom gland has been mainly studied in parasitoids developing in larval or pupal hosts while little is known for parasitoids developing in insect eggs. We conducted the first extensive characterization of the venom of the endoparasitoid Ooencyrtus telenomicida (Vassiliev), a species that develops in eggs of the stink bug Nezara viridula (L.). In particular we investigated the structure of the venom apparatus, its functio…
New national and regional bryophyte records, 51
2017
1. Aloina rigida (Hedw.) Limpr.Contributors: O. Yu. Pisarenko, V. E. Fedosov and V. A. BakalinRussia: Primorsky Territory, Dalnegorsky District, vicinity of Dalnegorsk Town, NE-facing steep slope o...
Highly contrasted population genetic structures in a host-parasite pair in the Caribbean Sea.
2017
Evolution and population genetic structure of marine species across the Caribbean Sea are shaped by two complex factors: the geological history and the present pattern of marine currents. Characterizing and comparing the genetic structures of codistributed species, such as host–parasite associations, allow discriminating the relative importance of environmental factors and life history traits that influenced gene flow and demographic events. Using microsatellite and Cytochrome Oxidase I markers, we investigated if a host–parasite pair (the heart urchin Meoma ventricosa and its parasitic pea crab Dissodactylus primitivus) exhibits comparable population genetic structures in the Caribbean Sea…
Aging parasites produce offspring with poor fitness prospects.
2017
Senescing individuals have poor survival prospects and low fecundity. They can also produce offspring with reduced survival and reproductive success. We tested the effect of parental age on the performance of descendants in the nematode Heligmosomoides polygyrus , an intestinal parasite of rodents. We found that offspring of senescing worms had reduced within-host survival and reduced egg shedding over the first month post-infection compared with offspring produced by young parents. These results suggest that declining offspring quality is a component of senescence in parasitic nematodes and might have evolutionary consequences for the optimal schedule of age-dependent investment into repr…
Early Plasmodium-induced inflammation does not accelerate aging in mice
2019
10 pages; International audience; Aging is associated with a decline of performance leading to reduced reproductive output and survival. While the antagonistic pleiotropy theory of aging has attracted considerable attention, the molecular/physiological functions underlying the early-life benefits/late-life costs paradigm remain elusive. We tested the hypothesis that while early activation of the inflammatory response confers benefits in terms of protection against infection, it also incurs costs in terms of reduced reproductive output at old age and shortened longevity. We infected mice with the malaria parasite Plasmodium yoelii and increased the inflammatory response using an anti-IL-10 r…
Contrasting biogeographical patterns in Margarella (Gastropoda: Calliostomatidae: Margarellinae) across the Antarctic Polar Front
2021
International audience; Members of the trochoidean genus Margarella (Calliostomatidae) are broadly distributed across Antarctic and sub-Antarctic ecosystems. Here we used novel mitochondrial and nuclear gene sequences to clarify species boundaries and phylogenetic relationships among seven nominal species distributed on either side of the Antarctic Polar Front (APF). Molecular reconstructions and species-delimitation analyses recognized only four species: M. antarctica (the Antarctic Peninsula), M. achilles (endemic to South Georgia), M. steineni (South Georgia and Crozet Island) and the morphologically variable M. violacea (=M. expansa, M. porcellana and M. pruinosa), with populations in s…
Gastrointestinal parasites of two populations of Arctic foxes (Vulpes lagopus) from north-east Greenland
2017
Parasitological examination of 275 faecal samples from Arctic foxes (Vulpes lagopus) collected at Zackenberg Valley and Karupelv Valley in north-east Greenland from 2006 to 2008 was conducted using sieving and microscopy. Overall, 125 (45.5%) samples contained parasite eggs of Taenia crassiceps, Taenia serialis, Toxascaris leonina, Eucoleus boehmi, Physalopteridae and Ancylostomatidae, and Strongyloides-like larvae. As long-term ecological studies are conducted at both sampling locations, the present findings constitute a baseline data set for further parasitological monitoring.
Reaction norms of host immunity, host fitness and parasite performance in a mouse - intestinal nematode interaction.
2016
8 pages; International audience; The outcome of the encounter between a host and a parasite depends on the synergistic effects of the genetics of the two partners and the environment (sensulato) where the interaction takes place. Reaction norms can depict how host and parasite traits vary across environmental ranges for different genotypes. Here, we performed a large scale experiment where three strains of laboratory mice (SJL, BALB/c and CBA) were infected with four doses of the intestinal nematode Heligmosomoides polygyrus. An increasing infective dose can be considered as a proxy for the environment-dependent risk incontracting the infection. We looked at the fitness traits of hosts and …