Search results for "interactions."
showing 10 items of 1865 documents
Population sex-ratio affecting behavior and physiology of overwintering bank voles (Myodes glareolus)
2016
Many boreal rodents are territorial during the breeding season but during winter become social and aggregate for more energy efficient thermoregulation. Communal winter nesting and social interactions are considered to play an important role for the winter survival of these species, yet the topic is relatively little explored. Females are suggested to be the initiators of winter aggregations and sometimes reported to survive better than males. This could be due to the higher social tolerance observed in overwintering females than males. Hormonal status could also affect winter behavior and survival. For instance, chronic stress can have a negative effect on survival, whereas high gonadal ho…
Multi-infections of feminizing Wolbachia strains in natural populations of the terrestrial isopod Armadillidium vulgare.
2013
7 pages; International audience; Maternally inherited Wolbachia (α-Proteobacteria) are widespread parasitic reproductive manipulators. A growing number of studies have described the presence of different Wolbachia strains within a same host. To date, no naturally occurring multiple infections have been recorded in terrestrial isopods. This is true for Armadillidium vulgare which is known to harbor non simultaneously three Wolbachia strains. Traditionally, such Wolbachia are detected by PCR amplification of the wsp gene and strains are characterized by sequencing. The presence of nucleotide deletions or insertions within the wsp gene, among these three different strains, provides the opportu…
Do bank voles (Myodes glareolus) trapped in live and lethal traps show differences in tick burden?
2020
In studies assessing tick abundance, the use of live traps to capture and euthanize rodent hosts is a commonly used method to determine their burden. However, captive animals can experience debilitating or fatal capture stress as a result prior to collection. An alternative method is the use of lethal traps, but this can potentially lead to tick drop-off between the time of capture and collection. In this study, in order to determine whether subjecting animals to capture stress is inevitable, we tested the difference in sheep tick (Ixodes ricinus) larval burdens between bank voles (Myodes glareolus) captured alive and euthanized, and lethally trapped bank voles. During 2017 and 2018, 1318 b…
Widespread vertical transmission and associated host sex–ratio distortion within the eukaryotic phylum Microspora
2004
Vertical transmission (VT) and associated manipulation of host reproduction are widely reported among prokaryotic endosymbionts. Here, we present evidence for widespread use of VT and associated sex-ratio distortion in a eukaryotic phylum. The Microspora are an unusual and diverse group of eukaryotic parasites that infect all animal phyla. Following our initial description of a microsporidian that feminizes its crustacean host, we survey the diversity and distribution of VT within the Microspora. We find that vertically transmitted microsporidia are ubiquitous in the amphipod hosts sampled and that they are also diverse, with 11 species of microsporidia detected within 16 host species. We f…
The ecomorphology of southern African rodent incisors: Potential applications to the hominin fossil record.
2018
AbstractThe taxonomic identification of mammalian fauna within fossil assemblages is a well-established component of paleoenvironmental reconstructions. However, many fragmentary specimens recovered from fossil sites are often disregarded as they can be difficult to identify with the precision required for taxonomic methods. For this reason, the large numbers of isolated rodent incisors that are often recovered from hominin fossil bearing sites have generally been seen as offering little interpretive value. Ecomorphological analysis, often referred to as a “taxon-free” method, can potentially circumvent this problem by focusing on the adaptive, rather than the taxonomic significance of rode…
Identifying a key host in an acanthocephalan-amphipod system.
2015
SUMMARYTrophically transmitted parasites may use multiple intermediate hosts, some of which may be ‘key-hosts’, i.e. contributing significantly more to the completion of the parasite life cycle, while others may be ‘sink hosts’ with a poor contribution to parasite transmission. Gammarus fossarum and Gammarus roeseli are sympatric crustaceans used as intermediate hosts by the acanthocephalan Pomphorhynchus laevis. Gammarus roeseli suffers higher field prevalence and is less sensitive to parasite behavioural manipulation and to predation by definitive hosts. However, no data are available on between-host differences in susceptibility to P. laevis infection, making it difficult to untangle the…
Virgins in the wild: mating status affects the behavior of a parasitoid foraging in the field
2008
In haplodiploid organisms, virgin females can produce offspring, albeit only sons. They may therefore face a trade-off between either: (1) searching for hosts and producing sons immediately; or (2) searching for mates and perhaps producing both sons and daughters later in life. Although this trade-off raises a theoretical interest, it has not been approached experimentally. The objective of this article is thus to document the effect of mating status on the foraging behavior of a haplodiploid parasitoid. For this, we recorded the behavior of virgin and mated female Lysiphlebus testaceipes (Hymenoptera: Braconidae) after being released, in the field, on a colony of their aphid hosts. Half of…
Fungal-Mediated Multitrophic Interactions : Do Grass Endophytes in Diet Protect Voles from Predators?
2009
Plant-associated micro-organisms such as mycotoxin-producing endophytes commonly have direct negative effects on herbivores. These effects may be carried over to natural enemies of the herbivores, but this has been rarely explored. We examined how feeding on Neotyphodium endophyte infected (E+) and endophyte free (E−) meadow ryegrass (Scherodonus pratensis) affects body mass, population size and mobility of sibling voles (Microtus levis), and whether the diet mediates the vulnerability of voles to least weasel (Mustela nivalis nivalis) predation. Because least weasels are known to be olfactory hunters, we also examined whether they are able to distinguish olfactory cues of voles fed on E+ a…
Influence of microbial symbionts on insect pheromones
2018
Covering: up to 2018 Pheromones serve as chemical signals between individuals of the same species and play important roles for mate localization and mate choice as well as other social interactions in insects. A growing body of literature indicates that microbial symbionts can modulate their hosts' chemical profiles, mate choice decisions and social behavior. This modulation can occur by the direct biosynthesis of pheromone components or the provisioning of precursors, or through general changes in the metabolite pool of the host and its resource allocation into pheromone production. Here we review and discuss the contexts in which microbial modulation of intraspecific communication in inse…
Interference with purinergic signalling
2016
Objective: The association of abacavir (ABC), a guanosine analogue, with cardiovascular toxicity is a long-lasting matter of controversy engendered by the lack of a mechanism of action. Clinical data point to an acute mechanism of vascular inflammation. Previous studies have shown that ABC induces leukocyte-endothelial cell interactions, an indicator of vascular inflammation. These effects are reproduced by another purine analogue, didanosine, but not by pyrimidine or acyclic nucleotide analogues, hinting at an interference with the purinergic system. The aim of the present study was to assess the role of ATP-receptors in leukocyte accumulation induced by ABC. Design and methods: Clinical c…