Advances in mosquito repellents: effectiveness of citronellal derivatives in laboratory and field trials

BACKGROUND Several essential oils, including citronella (lemongrass, Cymbopogon sp., Poaceae), are well-known mosquito repellents. A drawback of such products is their limited protection time resulting from the high volatility of their active components. In particular, citronella oil protects for <2 h, although formulations with fixatives can increase this time. RESULTS We synthesized hydroxylated cyclic acetals of citronellal, the main component of citronella, to obtain derivatives with lower volatility and weaker odour. The crude mixture of isomers obtained in the reaction was tested under laboratory conditions for its repellency against two mosquito species, the major malaria vector Anopheles gambiae and the arbovirus vector Aedes albopictus, and found to be endowed with longer protection time with respect to DEET (N,N-diethyl-meta-toluamide) at the same concentration. Formulated products were tested in a latin square human field trial, in an area at a high density of A. albopictus for 8 h from the application. We found that the performance of the citronellal derivatives mixture is comparable (95% protection for <= 3.5 h) with those of the most widespread synthetic repellents DEET and Icaridin, tested at a four-fold higher doses. CONCLUSIONS Modifying the hydrophilicity and volatility of natural repellents is a valuable strategy to design insect repellents with a long-lasting effect. (c) 2022 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry

Increased immunocompetence and network centrality of allogroomer workers suggest a link between individual and social immunity in honeybees.

The significant risk of disease transmission has selected for effective immune-defense strategies in insect societies. Division of labour, with individuals specialized in immunity-related tasks, strongly contributes to prevent the spread of diseases. A trade-off, however, may exist between phenotypic specialization to increase task efficiency and maintenance of plasticity to cope with variable colony demands. We investigated the extent of phenotypic specialization associated with a specific task by using allogrooming in the honeybee, Apis mellifera, where worker behaviour might lower ectoparasites load. We adopted an integrated approach to characterize the behavioural and physiological phenotype of allogroomers, by analyzing their behavior (both at individual and social network level), their immunocompetence (bacterial clearance tests) and their chemosensory specialization (proteomics of olfactory organs). We found that allogroomers have higher immune capacity compared to control bees, while they do not differ in chemosensory proteomic profiles. Behaviourally, they do not show differences in the tasks performed (other than allogrooming), while they clearly differ in connectivity within the colonial social network, having a higher centrality than control bees. This demonstrates the presence of an immune-specific physiological and social behavioural specialization in individuals involved in a social immunity related task, thus linking individual to social immunity, and it shows how phenotypes may be specialized in the task performed while maintaining an overall plasticity

Tracing the dispersal route of the invasive Japanese beetle Popillia japonica

The Japanese beetle, Popillia japonica, is a highly polyphagous Scarabaeidae native to Japan that colonized North America and Azores in the last century and has recently invaded Italy and Switzerland. Considering its economic impact on the horticulture and turfgrass industries, this species was ranked within the EU priority pests list in 2019. According to the EU Convention on Biological Diversity, the identification of invasion routes is a pivotal aspect in an effective management program aimed at controlling invasive alien species. To reconstruct the source of introductions of this pest, we investigated the genetic variability of P. japonica in its native and invaded areas worldwide by analyzing 9 microsatellite loci and two mitochondrial genes, COX I and CytB. In its native area, P. japonica is structured into two populations: one in the southern and another in the northern-central region of Japan. A limited area within central Japan was identified as the putative source of the North American outbreak. Moreover, the ABC inference and phylogeographic reconstruction suggest that two European populations originated from two independent introductions. The Azores Islands outbreak occurred approximately 50 years ago and originated from the southeastern region of North America (For simplicity, in this paper North America refers to Canada and the USA), while the second introduction, more recently, occurred in Italy and Switzerland and originated from northeastern region of North America

Expression in Antennae and Reproductive Organs Suggests a Dual Role of an Odorant-Binding Protein in Two Sibling Helicoverpa Species

Odorant-binding proteins (OBPs) mediate both perception and release of semiochemicals in insects. These proteins are the ideal targets for understanding the olfactory code of insects as well as for interfering with their communication system in order to control pest species. The two sibling Lepidopteran species Helicoverpa armigera and H. assulta are two major agricultural pests. As part of our aim to characterize the OBP repertoire of these two species, here we focus our attention on a member of this family, OBP10, particularly interesting for its expression pattern. The protein is specifically expressed in the antennae of both sexes, being absent from other sensory organs. However, it is highly abundant in seminal fluid, is transferred to females during mating and is eventually found on the surface of fertilised eggs. Among the several different volatile compounds present in reproductive organs, OBP10 binds 1-dodecene, a compound reported as an insect repellent. These results have been verified in both H. armigera and H. assulta with no apparent differences between the two species. The recombinant OBP10 binds, besides 1-dodecene, some linear alcohols and several aromatic compounds. The structural similarity of OBP10 with OBP1 of the mosquito Culex quinquefasciatus, a protein reported to bind an oviposition pheromone, and its affinity with 1-dodecene suggest that OBP10 could be a carrier for oviposition deterrents, favouring spreading of the eggs in these species where cannibalism is active among larvae

DTT - Divertor Tokamak Test facility: A testbed for DEMO

The effective treatment of the heat and power exhaust is a critical issue in the road map to the realization of the fusion energy. In order to provide possible, reliable, well assessed and on-time answers to DEMO, the Divertor Tokamak Test facility (DTT) has been conceived and projected to be carried out and operated within the European strategy in fusion technology. This paper, based on the invited plenary talk at the 31st virtual SOFT Conference 2020, provides an overview of the DTT scientific proposal, which is deeply illustrated in the 2019 DTT Interim Design Report

Cryptic dispersal of Cyanidiophytina (Rhodophyta) in non-acidic environments from Turkey

Cyanidiophytina are a group of polyextremophilic red algae with a worldwide, but discontinuous colonization. They are restricted to widely dispersed hot springs, geothermal habitats, and also some human-altered environments. Cyanidiophytina are predominant where pH is prohibitive for the majority of eukaryotes (pH 0.5-3). Turkey is characterized by areas rich in volcanic activity separated by non-volcanic areas. Here we show that Cyanidiophycean populations are present in thermal baths located around Turkey on neutral/alkaline soils. All known genera and species within Cyanidiophytina were detected in Turkey, including Galdieria phlegrea, recorded up to now only in Italian Phlegrean Fields. By phylogenetic analyses, Turkish G. sulphuraria strains are monophyletic with Italian and Icelandic strains, and with Russian G. daedala strains. G. maxima from Turkey clustered with Icelandic, Kamchatka, and Japanese populations. The discovery of Cyanidiophytina in non-acidic Turkish soils raises new questions about the ecological boundaries of these extremophilic algae. This aids in the understanding of the dispersal abilities and distribution patterns of this ecologically and evolutionarily interesting group of algae

DTT - Divertor Tokamak Test facility - Interim Design Report

The “Divertor Tokamak Test facility, DTT” is a milestone along the international program aimed at demonstrating – in the second half of this century – the feasibility of obtaining to commercial electricity from controlled thermonuclear fusion. DTT is a Tokamak conceived and designed in Italy with a broad international vision. The construction will be carried out in the ENEA Frascati site, mainly supported by national funds, complemented by EUROfusion and European incentive schemes for innovative investments. The project team includes more than 180 high-standard researchers from ENEA, CREATE, CNR, INFN, RFX and various universities. The volume, entitled DTT Interim Design Report (“Green Book” from the colour of the cover), briefly describes the status of the project, the planning of the design future activities and its organizational structure. The publication of the Green Book also provides an occasion for thorough discussions in the fusion community and a broad international collaboration on the DTT challenge

Alfalfa saponins in Popillia japonica control

Raw data of the experiments described in the following publication: "Antifeedant and insecticidal effects of alfalfa saponins in the management of the Japanese beetle Popillia japonica" submitted to the Journal of Applied Entomology

Influence of surface roughness on the bond of FRP laminates to concrete

The potential of Fiber Reinforced Polymer FRP in the reinforcement of concrete structures has been shown in many studies and practical applications. However, few works have been focused systematically on the development of quantitative criteria to measure surface roughness and relate this parameter to the debonding stress. Roughness has a direct influence on the FRP performance in terms of bond to concrete, which is important to ensure the effectiveness of the external FRP reinforcement. Currently, there is not much evidence about the parameters related to surface state of concrete structures nor many guidelines about assessing the optimal conditions of concrete surface for the application of the FRP. To respond to these needs, the presented study deals with the effects of the surface characteristics of concrete on debonding strength of the FRP; this objective has been pursued by means of experimental tests on concrete specimens characterized by different levels of roughness of the concrete surface. The paper describes the experimental campaign outlining the analyzed surface preparation procedures (i.e., sandblast, bush-ammering, grinding, brushing) and the subsequent tests performed on the installed FRP by means of two different test methods. The former is a laboratory method which performs shear tests to evaluate the debonding shear strength of the FRP reinforcement; the latter is pull-out test which is a typical method used for in situ check of quality of the FRP application. The results of these experimental tests are discussed in the paper with emphasis on the correlation between the roughness of the surface and the outcomes of both shear and pull-out tests; this information can be used in design in order to prescribe the minimum roughness level necessary to attain the expected debonding strength of the reinforcement