Diploid males support a two-step mechanism of endosymbiont-induced thelytoky in a parasitoid wasp.

BACKGROUND: Haplodiploidy, where females develop from diploid, fertilized eggs and males from haploid, unfertilized eggs, is abundant in some insect lineages. Some species in these lineages reproduce by thelytoky that is caused by infection with endosymbionts: infected females lay haploid eggs that undergo diploidization and develop into females, while males are very rare or absent. It is generally assumed that in thelytokous wasps, endosymbionts merely diploidize the unfertilized eggs, which would then trigger female development. RESULTS: We found that females in the parasitoid wasp Asobara japonica infected with thelytoky-inducing Wolbachia produce 0.7-1.2 % male offspring. Seven to 39 % of these males are diploid, indicating that diploidization and female development can be uncoupled in A. japonica. Wolbachia titer in adults was correlated with their ploidy and sex: diploids carried much higher Wolbachia titers than haploids, and diploid females carried more Wolbachia than diploid males. Data from introgression lines indicated that the development of diploid individuals into males instead of females is not caused by malfunction-mutations in the host genome but that diploid males are most likely produced when the endosymbiont fails to activate the female sex determination pathway. Our data therefore support a two-step mechanism by which endosymbionts induce thelytoky in A. japonica: diploidization of the unfertilized egg is followed by feminization, whereby each step correlates with a threshold of endosymbiont titer during wasp development. CONCLUSIONS: Our new model of endosymbiont-induced thelytoky overthrows the view that certain sex determination mechanisms constrain the evolution of endosymbiont-induced thelytoky in hymenopteran insects. Endosymbionts can cause parthenogenesis through feminization, even in groups in which endosymbiont-diploidized eggs would develop into males following the hosts' sex determination mechanism. In addition, our model broadens our understanding of the mechanisms by which endosymbionts induce thelytoky to enhance their transmission to the next generation. Importantly, it also provides a novel window to study the yet-poorly known haplodiploid sex determination mechanisms in haplodiploid insects

Temperature stress increases hybrid incompatibilities in the parasitic wasp genus <i>Nasonia</i>

Hybrid incompatibilities, measured as mortality and sterility, are caused by the disruption of gene interactions. They are important post-zygotic isolation barriers to species hybridization, and much effort is put into the discovery of the genes underlying these incompatibilities. In hybridization studies of the haplodiploid parasitic wasp genus Nasonia, genic incompatibilities have been shown to affect mortality and sterility. The genomic regions associated with mortality have been found to depend on the cytotype of the hybrids and thus suggest cytonuclear incompatibilities. As environmental conditions can affect gene expression and gene interaction, we here investigate the effect of developmental temperature on sterility and mortality in Nasonia hybrids. Results show that extreme temperatures strongly affect both hybrid sterility (mainly spermatogenic failure) and mortality. Molecular mapping revealed that extreme temperatures increase transmission ratio distortion of parental alleles at incompatible loci, and thus, cryptic incompatible loci surface under temperature stress that remain undiscovered under standard temperatures. Our results underline the sensitivity of hybrid incompatibilities to environmental factors and the effects of unstable epistasis

Quantitative Trait Locus Analysis of Mating Behavior and Male Sex Pheromones in Nasonia Wasps.

A major focus in speciation genetics is to identify the chromosomal regions and genes that reduce hybridization and gene flow. We investigated the genetic architecture of mating behavior in the parasitoid wasp species pair Nasonia giraulti and Nasonia oneida that exhibit strong prezygotic isolation. Behavioral analysis showed that N. oneida females had consistently higher latency times and broke off the mating sequence more often in the mounting stage when confronted with N. giraulti males compared with males of their own species. N. oneida males produce a lower quantity of the long-range male sex pheromone, (4R,5S)-5-hydroxy-4-decanolide (RS-HDL). Crosses between the two species yielded hybrid males with various pheromone quantities and these males were used in mating trials with females of either species to measure female mate discrimination rates. A quantitative trait locus (QTL) analysis involving 475 recombinant hybrid males (F2), 2148 reciprocally backcrossed females (F3), and a linkage map of 52 equally spaced neutral single nucleotide polymorphism (SNP) markers plus SNPs in 40 candidate mating behavior genes revealed four QTL for male pheromone amount depending on partner species. Our results demonstrate that the RS-HDL pheromone plays a role in the mating system of N. giraulti and N. oneida, but also that additional communication cues are involved in mate choice. No QTL were found for female mate discrimination which points at a polygenic architecture of female choice with strong environmental influences

Cloud Providers Viability: How to Address it from an IT and Legal Perspective?

A major part of the commercial Internet is moving towards a cloud paradigm. This phenomenon has a drastic impact on the organizational structures of enterprises and introduces new challenges that must be properly addressed to avoid major setbacks. One such challenge is that of cloud provider viability, that is, the reasonable certainty that the Cloud Service Provider (CSP) will not go out of business, either by filing for bankruptcy or by simply shutting down operations, thus leaving its customers stranded without an infrastructure and, depending on the type of cloud service used, even without their applications or data. This article attempts to address the issue of cloud provider viability, proposing some ways of mitigating the problem both from a technical and from a legal perspective

Estimation of Resilience Parameters Following LPS Injection Based on Activity Measured With Computer Vision

Resilience could be referred to as the animal’s ability to successfully adapt to a challenge. This is typically displayed by a quick return to initial metabolic or activity levels and behaviors. Pigs have distinct diurnal activity patterns. Deviations from these patterns could potentially be utilized to quantify resilience. However, human observations of activity are labor intensive and not feasible in practice on a large scale. In this study, we show the use of a computer vision tracking algorithm to quantify resilience based on activity individual patterns following a lipopolysaccharide (LPS) challenge, which induced a sickness response. We followed 121 individual pigs housed in barren or enriched housing systems, as previous work suggests an impact of housing on resilience, for eight days. The enriched housing consisted of delayed weaning in a group farrowing system and extra space compared with the barren pens and environmental enrichment. Enriched housed pigs were more active pre-injection of LPS, especially during peak activity times, than barren housed pigs (49.4 ± 9.9 vs. 39.1 ± 5.0 meter/hour). Four pigs per pen received an LPS injection and two pigs a saline injection. LPS injected animals were more likely to show a dip in activity than controls (86% vs 17%). Duration and Area Under the Curve (AUC) of the dip were not affected by housing. However, pigs with the same AUC could have a long and shallow dip or a steep and short dip. Therefore the AUC:duration ratio was calculated, and enriched housed pigs had a higher AUC:duration ratio compared to barren housed pigs (9244.1 ± 5429.8 vs 5919.6 ± 4566.1). Enriched housed pigs might therefore have a different strategy to cope with an LPS sickness challenge. However, more research on this strategy and the use of activity to quantify resilience and its relationship to physiological parameters is therefore needed

Skin and liver diseases induced in flounder (Platichthys flesus) after long-term exposure to contaminated sediments in large-scale mesocosms.

Disease development in flounder (Platichthys flesus) was studied over a period of 3 years in three large mesocosms (40 m x 40 m x 3 m). Two of the mesocosms contained clean sand and the third, sharing a common water circulation with one of the clean-sand mesocosms, was stocked with contaminated dredged spoil. In this way, one of the clean-sand mesocosms was indirectly polluted via the water phase, and analysis of contaminant concentrations in sediments and flounder tissues showed that it had a status intermediate between the other two. Random samples of the flounder populations from the indirectly polluted and reference mesocosms were examined every 2 months for epidermal diseases (lymphocystis, skin ulcers, fin rot) and then released. In addition, every 6 months, random samples of fish from all three mesocosms were sacrificed for histological and chemical investigation. With regard to the development of epidermal disease, the results showed little difference between the reference mesocosm and the indirectly polluted mesocosm, with the exception that lymphocystis was significantly elevated in the indirectly polluted mesocosm. Although pollution may be a risk factor in the etiology of this disease, such a relationship would probably be obscured under field conditions due to variation arising from other factors. Histopathological analysis of the livers revealed in total four cases of hepatocellular adenoma (1.5% of sampled population) in fish from the polluted mesocosms, the first occurring after 2.5 years of exposure in fish from the indirectly polluted mesocosm. Furthermore, several other liver lesions, including foci of cellular alteration and hydropic vacuolated lesions, developed during the course of the experiment before tumor formation was apparent. Prevalences of these conditions were very much lower in the reference mesocosm than in the two polluted mesocosms. Densities of melanomacrophage centers in the liver showed a similar trend. The findings clearly indicate that long-term exposure to chemically contaminated dredged spoil can induce liver neoplasia and other liver lesions in flounder at contaminant levels comparable to those found in the natural environment

4 Decades of Belgian Marine Monitoring: uplifting historical data to today’s needs - Final Report

Context : Long-term quality checked and integrated datasets for the Belgian Part of the North Sea (BPNS) are essential to detect changes in this complex ecosystem and support policy related decisions.Objectives: - Compile and safeguard quality checked, intercalibrated and integrated datasets and make them publicly accessible for further research and policy purposes.- Improve or develop methods and protocols to assess and interpret environmental change in the BPNS and compare trends with neighbouring areas.- Provide support and advice for policy related decisions and legal measures, like MSFD and OSPAR.Conclusions: A scheme with data management tools has been worked out for efficient data flow throughout the project. The scheme, including the mandatory metadata fields and standardization, can be used as a guideline for future projects. Inventories of datasources, projects and data-originators were compiled and the final datasets are available via the central dataportal. Even after compiling and quality checking the long-term datasets, the scientists had to consider some limitations, like changing methodologies and low data resolution, and incorporate these into their trend analyses procedures. Some remarkable environmental changes over time were observed. Model results of the contaminants showed decreasing trends for heavy metals and PCBs. Zn concentrations, however, were found increasing in marine sediments while As concentrations were found increasing in groyne mussels. Nearby the port of Zeebrugge and the mouth of the Scheldt, PCB concentrations were found slightly increasing again over the last decade. The study on eutrophication showed that nutrient (N, P) riverine concentrations and loads have decreased continuously from the end of the 1980‟s to now. However, this did not result in a comparable decrease of marine nutrient concentrations. No clear long-term trend effect was observed on in situ chlorophyll a concentrations following the nutrient decrease. However, a clear change in chlorophyll a phenology followed the increase in sea surface temperature in the period. Furthermore, biomass, seasonality and structure of diatom and dinoflagellate communities were compared between the 1970s and 2000s for the Belgian Part of the North Sea (BPNS), derived from the newly established Belgian Phytoplankton Database. Distinct changes were observed: changes in diatom and dinoflagellate biomass and shift of fulcrum; changes in community structure, with a trend towards seasonal homogenization in the diatom community; increased occurrence of harmful diatom (Pseudo-nitzschia) and dinoflagellate (e.g. Prorocentrum) genera. The observed changes correlate well with overall increases in temperature and changes in nutrient loads and ratios.And finally, for acidification, pH data reveal an increasing trend from the mid-70‟s to the mid-80‟s and a decrease of pH from the mid-80‟s onwards that seems consistent with changes in primary production patterns. The comparison of CH4 concentrations obtained in 1990 and 2016, showed a decreasing trend consistent with alleviation of eutrophication in the area.Based on the outcome of this successful project, the partners defined various recommendations regarding future monitoring strategies for policy makers

Pesticide Exposure of Residents Living Close to Agricultural Fields in the Netherlands:Protocol for an Observational Study

Background: Application of pesticides in the vicinity of homes has caused concern regarding possible health effects in residents living nearby. However, the high spatiotemporal variation of pesticide levels and lack of knowledge regarding the contribution of exposure routes greatly complicates exposure assessment approaches. Objective: The objective of this paper was to describe the study protocol of a large exposure survey in the Netherlands assessing pesticide exposure of residents living close ( Methods: We performed an observational study involving residents living in the vicinity of agricultural fields and residents living more than 500 m away from any agricultural fields (control subjects). Residential exposures were measured both during a pesticide use period after a specific application and during the nonuse period for 7 and 2 days, respectively. We collected environmental samples (outdoor and indoor air, dust, and garden and field soils) and personal samples (urine and hand wipes). We also collected data on spraying applications as well as on home characteristics, participants' demographics, and food habits via questionnaires and diaries. Environmental samples were analyzed for 46 prioritized pesticides. Urine samples were analyzed for biomarkers of a subset of 5 pesticides. Alongside the field study, and by taking spray events and environmental data into account, we developed a modeling framework to estimate environmental exposure of residents to pesticides. Results: Our study was conducted between 2016 and 2019. We assessed 96 homes and 192 participants, including 7 growers and 28 control subjects. We followed 14 pesticide applications, applying 20 active ingredients. We collected 4416 samples: 1018 air, 445 dust (224 vacuumed floor, 221 doormat), 265 soil (238 garden, 27 fields), 2485 urine, 112 hand wipes, and 91 tank mixtures. Conclusions: To our knowledge, this is the first study on residents' exposure to pesticides addressing all major nondietary exposure sources and routes (air, soil, dust). Our protocol provides insights on used sampling techniques, the wealth of data collected, developed methods, modeling framework, and lessons learned. Resources and data are open for future collaborations on this important topic