Search results for "PTE"
showing 10 items of 2238 documents
Observations on midgut of Apis mellifera workers (Hymenoptera: Apoidea) under controlled acute exposures to a Bacillus thuringiensis-based biopestici…
2016
International audience; AbstractMorphostructural investigations have been carried out on Apis mellifera workers treated with single controlled acute exposures to a biopesticide containing Bacillus thuringiensis (Bt), to detect midgut changes until 96 h. Our findings show concentration-dependence of these changes, reflecting in different degrees on both mortality and behaviour. In particular, some midgut changes are also found 96 h after treatment. Our results show that the tested product does not affect survival at presumable environmental concentrations, so confirming the lesser toxicity of Bt-based biopesticides compared to other pesticides. However, in the light of the discovered long-te…
When phenotypes fail to illuminate underlying genetic processes in fish and fisheries science
2019
Abstract Advances in genetic and genomic technologies have become widely available and have potential to provide novel insights into fish biology and fisheries science. In the present overview, we explore cases for which genomic analyses have proven instrumental in the rejection of hypotheses that have been well-motivated based on phenotypic and ecological properties of individuals and populations. We focus on study systems for which information derived using genomic tools contradicts conclusions drawn from traditional fisheries science methodologies and assumptions. We further illustrate the non-intuitive interplay of genomics and ecology in Atlantic salmon (Salmo salar L.) owing to the re…
Learned parasite avoidance is driven by host personality and resistance to infection in a fish-trematode interaction
2016
Cognitive abilities related to the assessment of risk improve survival. While earlier studies have examined the ability of animals to learn to avoid predators, learned parasite avoidance has received little interest. In a series of behavioural trials with the trematode parasite Diplostomum pseudospathaceum , we asked whether sea trout ( Salmo trutta trutta ) hosts show associative learning in the context of parasitism and if so, whether learning capacity is related to the likelihood of infection mediated through host personality and resistance. We show that animals are capable of learning to avoid visual cues associated with the presence of parasites. However, avoidance behaviour ceased af…
Taxonomic status and epidemiology of the mesoparasitic copepod Pennella balaenoptera in cetaceans from the western Mediterranean.
2018
Pennella balaenoptera is a mesoparasitic copepod that has been reported in at least 17 cetacean species. Subtle morphological differences in the first antennae of adult females have been used to discriminate this species from P. filosa, a species infecting fishes. Other morphological traits are unreliable because of their high plasticity, and no molecular data are available to confirm the taxonomic status of P. balaenoptera as an independent species. We found no consistent morphological differences of the first antennae between P. balaenoptera and P. filosa collected from cetaceans and fish in the western Mediterranean. Molecular data on the mitochondrial cytochrome oxidase subunit I failed…
Phylogeny and the colourful history of jewel bugs (Insecta: Hemiptera: Scutelleridae)
2017
Members of the family Scutelleridae (Heteroptera: Pentatomomorpha: Pentatomoidea) are also called shield bugs because of the greatly enlarged scutellum, or jewel bugs because of the brilliant colours of many species. All scutellerids are phytophagous, feeding on various parts of their host plants. Due to lack of obvious synapomorphies and the failure to apply rigorous phylogenetic methods, the higher classification of Scutelleridae has been disputed for more than 150 years. Here we reconstructed a phylogeny of Scutelleridae based on complete sequences of 18S and 28S nuclear rDNAs and all 13 protein-coding genes of the mitochondrial genome, with the sampled taxa covering all of the currently…
Bone histology, microanatomy, and growth of the nothosauroid Simosaurus gaillardoti (Sauropterygia) from the Upper Muschelkalk of southern Germany/Ba…
2016
Abstract Simosaurus gaillardoti was a large eosauropterygian (Sauropterygia), a group of diverse diapsid marine reptiles. Its occurrence correlates to transgression phases in the Germanic Basin and a former morphological study hypothesized that Simosaurus was capable of sustained swimming. Microanatomical analysis of five long bones revealed functional differences between the humerus and femur but did not confirm sustained swimming in Simosaurus. It had certain active swimming abilities but – based on microanatomy – it was a less efficient swimmer when compared to contemporaneously living nothosaurs. Simosaurus grew with well-vascularized coarse parallel-fibred bone tissue. Growth marks app…
Karyotype variability and inter-population genomic differences in freshwater ostracods (Crustacea) showing geographical parthenogenesis
2018
Transitions from sexual to asexual reproduction are often associated with polyploidy and increased chromosomal plasticity in asexuals. We investigated chromosomes in the freshwater ostracod species Eucypris virens (Jurine, 1820), where sexual, asexual and mixed populations can be found. Our initial karyotyping of multiple populations from Europe and North Africa, both sexual and asexual, revealed a striking variability in chromosome numbers. This would suggest that chromosomal changes are likely to be accelerated in asexuals because the constraints of meiosis are removed. Hence, we employed comparative genomic hybridization (CGH) within and among sexual and asexual populations to get insigh…
Angiosperm to Gymnosperm host-plant switch entails shifts in microbiota of the Welwitschia bug, Probergrothius angolensis (Distant, 1902).
2019
The adaptation of herbivorous insects to new host plants is key to their evolutionary success in diverse environments. Many insects are associated with mutualistic gut bacteria that contribute to the host's nutrition and can thereby facilitate dietary switching in polyphagous insects. However, how gut microbial communities differ between populations of the same species that feed on different host plants remains poorly understood. Most species of Pyrrhocoridae (Hemiptera: Heteroptera) are specialist seed-feeders on plants in the family Malvaceae, although populations of one species, Probergrothius angolensis, have switched to the very distantly related Welwitschia mirabilis plant in the Nami…
Experience and dominance in fish pairs jointly shape parasite avoidance behaviour
2018
There is increasing evidence that the composition of a social group influences the fitness of its members. For example, group member identities can determine the exposure risk to contact-transmitted parasites and consequently impact the health of all group members. Here, we propose that group composition may also affect host exposure to parasite propagules prevailing in the environment via collective parasite avoidance behaviours. We explored the spatial avoidance of a trematode parasite, Diplostomum pseudospathaceum, using the simplest form of host groups, pairs of sea trout, Salmo trutta trutta. These pairs showed either (1) between-group heterogeneity in their experience with the parasit…