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Archaeology
Surface texture analysis in Toothfrax and MountainsMap® SSFA module: Different software packages, different results?
10.24072/pcjournal.204 - Peer Community Journal, Volume 2 (2022), article no. e77.
Get full text PDFThe scale-sensitive fractal analysis (SSFA) of dental microwear textures is traditionally performed using the software Toothfrax. SSFA has been recently integrated to the software MountainsMap® as an optional module. Meanwhile, Toothfrax support has ended. Before switching to the new module, the outputs between the two software packages must be compared for consistency. We have performed such a test using Bayesian modelling on three datasets including dental surfaces of sheep (Merceron, Ramdarshan, et al., 2016) and guinea pigs (Winkler, Schulz-Kornas, Kaiser, Cuyper, et al., 2019) from controlled feeding experiments, as well as surfaces of quartzite and flint flakes used in an actualistic archeological experiment on cleaning procedures (Pedergnana, Calandra, Bob, et al., 2020). We found that the two software packages calculate significantly different values for the SSFA parameters epLsar, Asfc, HAsfc9 and R2, even when the same settings are used. Nevertheless, the treatments (different diets or cleaning procedures) are discriminated similarly within each dataset. While the new software module is as good as the original software to differentiate treatments, our results imply that the outputs from the two software packages are not directly comparable and, as such, cannot be merged. Surface texture analysts should therefore consider re-analyzing published surfaces before integrating them in their studies.
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Ecology
Positive fitness effects help explain the broad range of Wolbachia prevalences in natural populations
10.24072/pcjournal.202 - Peer Community Journal, Volume 2 (2022), article no. e76.
Get full text PDFThe bacterial endosymbiont Wolbachia is best known for its ability to modify its host’s reproduction by inducing cytoplasmic incompatibility (CI) to facilitate its own spread. Classical models predict either near-fixation of costly Wolbachia once the symbiont has overcome a threshold frequency (invasion barrier), or Wolbachia extinction if the barrier is not overcome. However, natural populations do not all follow this pattern: Wolbachia can also be found at low frequencies (below one half) that appear stable over time. Wolbachia is known to have pleiotropic fitness effects (beyond CI) on its hosts. Existing models typically focus on the possibility that these are negative. Here we consider the possibility that the symbiont provides direct benefits to infected females (e.g. resistance to pathogens) in addition to CI. We discuss an underappreciated feature of Wolbachia dynamics: that CI with additional fitness benefits can produce low-frequency (< 1/2) stable equilibria. Additionally, without a direct positive fitness effect, any stable equilibrium close to one half will be sensitive to perturbations, which make such equilibria unlikely to sustain in nature. The results hold for both diplodiploid and different haplodiploid versions of CI. We suggest that insect populations showing low-frequency Wolbachia infection might host CI-inducing symbiotic strains providing additional (hidden or known) benefits to their hosts, especially when classical explanations (ongoing invasion, source-sink dynamics) have been ruled out.
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Archaeology
Raphana of the Decapolis and its successor Arpha - The search for an eminent Greco-Roman City
10.24072/pcjournal.201 - Peer Community Journal, Volume 2 (2022), article no. e75.
Get full text PDFThis research paper presents a detailed analysis of ancient literature and archaeological and geographical research until the present day for an important ancient location in the southern part of Syria. This one had different names during the time: Raepta, Raphana of the Decapolis, and later Arpha or Arefa. Moreover, the paper offers a more plausible location where Raphana, a Decapolis city named by Pliny the Elder, can be located. Ar-Rafi’ah, located in modern-day Syria, lies at an important geostrategic position close to a strong well, which is known today as Bir Qassab. It is highly plausible that this is where the ancient city mentioned above was situated. It can be shown within the literature analysis and maps that, due to completely different interpretations and in spite of missing archaeological evidence, many hypothetical locations were included in previous scientific literature. However, none of them fulfilled the requirements for the places described in the ancient literature. As a result, current well-researched literature provides the ancient Name of Raphana with question marks or even completely omits the name from listings or maps. Therefore, the last chapter focuses on the aforementioned unexplored and largely completely unknown location of Ar-Rafi’ah. In addition to a large main fortress and numerous probable civilian structures, an unusual accumulation of 11 new discovered auxiliary forts or “Stratopedon” can be proven in the presumed urban area. Remains of a Qanat and channel system clearly connected with this location can be detected over a length of more than 10km. Lastly, the shape of an extensive ruin inside the fortress city walls indicates a potential theatre or Odeon. Based on the geographical names that are still common today in the direct vicinity of localities, plains and way connections, the allocation becomes more and more plausible.
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Evolutionary Biology
Fitness costs and benefits in response to artificial artesunate selection in Plasmodium
10.24072/pcjournal.200 - Peer Community Journal, Volume 2 (2022), article no. e74.
Get full text PDFDrug resistance is a major issue in the control of malaria. Mutations linked to drug resistance often target key metabolic pathways and are therefore expected to be associated with biological costs. The spread of drug resistance depends on the balance between the benefits that these mutations provide in the drug-treated host and the costs they incur in the untreated host. The latter may therefore be expressed both in the vertebrate host and in the vector. Research on the costs of drug resistance focusses on interactions with vertebrate host, yet whether they are also expressed in the vector has been overlooked. In this study, we aim to identify the costs and benefits of resistance against artesunate (AS), one of the main artemisinin derivatives used in malaria-endemic countries. For this purpose, we compared different AS-selected lines of the avian malaria parasite Plasmodium relictum to their ancestral (unselected) counterpart. We tested their within host dynamics and virulence both in the vertebrate host and in its natural vector, the mosquito Culex quinquefasciatus. The within-host dynamics of the AS-selected lines in the treated birds was consistent with the phenotype of resistance described in human P. falciparum malaria: a clearance delay during the treatment followed by a recrudescence once the treatment was interrupted. In the absence of treatment, however, we found no significant costs of resistance in the bird. The results of the two experiments to establish the infectivity of the lines to mosquitoes point towards a decreased infectivity of the drug-selected lines as compared to the ancestral, reference one. We discuss the potential implication of these results on the spread of artesunate resistance in the field
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The network image was drawn by Martin Grandjean: A force-based network visualization CC BY-SA