The effects of host plant species and larval density on immune function in the polyphagous moth Spodoptera littoralis

Immune functions are costly, and immune investment is usually dependent on the individual's condition and resource availability. For phytophagous insects, host plant quality has large effects on performance, for example growth and survival, and may also affect their immune function. Polyphagous insects often experience a large variation in quality among different host plant species, and their immune investment may thus vary depending on which host plant species they develop on. Larvae of the polyphagous moth Spodoptera littoralis have previously been found to exhibit density-dependent prophylaxis as they invest more in certain immune responses in high population densities. In addition, the immune response of S. littoralis has been shown to depend on nutrient quality in experiments with artificial diet. Here, I studied the effects of natural host plant diet and larval density on a number of immune responses to understand how host plant species affects immune investment in generalist insects, and whether the density-dependent prophylaxis could be mediated by host plant species. While host plant species in general did not mediate the density-dependent immune expression, particular host plant species was found to increase larval investment in certain functions of the immune system. Interestingly, these results indicate that different host plants may provide a polyphagous species with protection against different kinds of antagonisms. This insight may contribute to our understanding of the relationship between preference and performance in generalists, as well as having applied consequences for sustainable pest management

Pheromonal variation and mating between two mitotypes of fall armyworm (Spodoptera frugiperda) in Africa

In the Americas, the fall armyworm (Spodoptera frugiperda) exists in two genetically distinct strains, the corn (C) and rice (R) strains. Despite their names, these strains are not associated with host plant preferences but have been shown to vary in pheromone composition and male responses. Recently, S. frugiperda was detected in Africa as an invasive species, but knowledge about variation in strain types, pheromone composition and inter-strain mating of populations of the pest in the continent has not been fully examined. Therefore, this study aimed to investigate variations, if any in the pheromone composition of female moths, male moth responses, and mating between C and R mitotypes of S. frugiperda populations in Kenya, as well as their geographic distribution. Strains (mitotypes) of S. frugiperda were identified using mitochondrial DNA (mtDNA) markers, and their pheromonal composition determined by coupled gas chromatography-mass spectrometric (GC-MS) analysis. Male moth responses to these compounds were evaluated using GC-electroantennographic detection (EAD), electroantennogram (EAG), and wind tunnel assays. Oviposition assays were used to determine whether R and C mitotype moths could mate and produce eggs. The results showed that both the R and C mitotypes were present, and there were no statistically significant differences in their distribution across all sampled locations. Five pheromone compounds including (Z)-7-dodecenyl acetate (Z7-12:OAc), (Z)-7-tetradecenyl acetate (Z7-14:OAc), (Z)-9-tetradecenyl acetate (Z9-14:OAc), (Z)-11-tetradecenyl acetate (Z11-14:OAc) and (Z)-11-hexadecenyl acetate (Z11-16:OAc), were detected in the pheromone glands of female moths of both mitotypes, with Z9-14:OAc being the most abundant. The relative percentage composition of Z9-14:OAc was similar in both mitotypes. However, the R mitotype had a 2.7 times higher relative percentage composition of Z7-12:OAc compared to the C mitotype moth, while the C mitotype moth had a 2.4 times higher relative percentage composition of Z11-16:OAc than the R mitotype moth. Male moths of both mitotypes exhibited similar responses to the pheromone compounds, showing the strongest responses to Z9-14:OAc and Z7-12:OAc in electrophysiological and behavioural assays. There was mating between R and C mitotypes with egg production comparable to mating within the same mitotype. Our results revealed that differences between the two S. frugiperda mitotypes are characterized by female moth pheromone composition rather than male moth responses to the pheromones, and that this does not prevent hybridisation between the mitotypes, which may have implications for their management

Odors Attracting the Long-Legged Predator Medetera signaticornis Loew to Ips typographus L. Infested Norway Spruce Trees

Predatory long-legged flies of the genus Medetera are important, but currently understudied, natural enemies of Scolytinae bark beetles such as Ips typographus. Medetera flies lay eggs on beetle-infested trees, where the developing larvae find their prey, but the chemical cues used by Medetera to locate infested trees are currently unknown. To identify odors attracting Medetera signaticornis, a species in Europe, headspace samples were collected at several time-points through different stages of I. typographus attacks on logs of Norway spruce (Picea abies). The headspace samples were analyzed using combined gas chromatography and mass spectrometry (GC-MS), and gas chromatography coupled with electroantennographic detection (GC-EAD) to determine compounds that stimulate M. signaticornis antennae. Antennae of M. signaticornis males and females were found to detect (-)-cis-verbenol, (+)-trans-verbenol and myrtenol, which are known to be produced by bark beetles. Antennal responses were also observed for verbenene, isoterpinolene, alpha-pinene oxide, camphor, pinocamphone, terpinene-4-ol, myrtenal, borneol, alpha-terpineol, geranyl acetone, and verbenone, which are primarily produced by microorganisms, and alpha-pinene, alpha-fenchene, beta-pinene, camphene, 3-carene, limonene, gamma-terpinene, and terpinolene, known spruce tree compounds. In field experiments testing two synthetic blends containing 18 antennal active and two additional compounds 2-methyl-3-buten-2-ol and ipsdienol we observed significant attraction of M. signaticornis within 24 h. These attractive blends can form the basis for development of Medetera monitoring lures for use in future forest and pest management

Antennal and maxillary palp morphology, and sensillar equipment, of the spruce bark beetle predators, Medetera signaticornis and Medetera infumata (Diptera: Dolichopodidae)

Many long-legged Medetera flies are natural enemies of bark beetle pests, which they detect using ol-factory cues, likely through olfactory sensilla on the antennae and maxillary palps. Morphological characterisation of olfactory sensilla among insects can provide a basis for future taxonomic, phyloge-netic or electrophysiological studies. Scanning electron microscopy was used to describe the morphology of olfactory organs and sensillar equipment of Medetera signaticornis and M. infumata. Three different olfactory sensillum types were found in both fly species, sensilla trichodea, s. basiconica and grooved pegs. Based on size and wall structure, s. trichodea and s. basiconica were categorised into different subtypes. Sharp-tipped curved s. trichodea, and small, large and thin s. basiconica were found on the antennal postpedicel of M. signaticornis adults, while grooved s. basiconica were found in M. infumata. The density of sharp-tipped long s. trichodea was significantly higher in males compared to females, and in M. signaticornis compared to M. infumata. Long-grooved s. basiconica were found grouped in a small pit on the maxillary palps of both species. Comparison of our results with the limited available ecological data suggests that differences in numbers of specific sensillum types may reflect adaptations related to olfactory-driven behaviours such as host seeking.(c) 2022 The Author(s). Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/)

Population comparison of innate and plastic host plant preference and performance in a polyphagous insect

During decision-making, animals may use either innate or plastic behaviours. This has been suggested to be important for generalist phytophagous insects where females need to assess a large range of cues during host plant selection for oviposition. To facilitate the choice, generalists may thus use innate preference hierarchies among host plants combined with phenotypic plasticity based on earlier host experience, but if populations differ in whether they rely on innate or plastic factors during decision-making is not well-known. Females from an Egyptian population of the polyphagous moth Spodoptera littoralis has previously been found to shift preference between plants in their innate preference hierarchy depending on larval host plant experience. We studied the innate preference hierarchy for three host plants (cotton, cabbage and cowpea), and whether the hierarchy shifts based on larval host plant experience, in a Northern range margin population (Italy) and a core population (Kenya) of S. littoralis, to see if and how these traits vary across populations. In addition, we studied larval performance on the three host plants in all three populations. The Italian and Kenyan populations had different innate preference hierarchies, and both hierarchies differed from the hierarchy that has previously been found in the Egyptian population. Furthermore, the host plant selection of ovipositing females was affected by larval diet in the Italian and Kenyan population, but the larval host plant experience did not completely shift the preference hierarchy as in the Egyptian population. This indicates that not only host plant preference per se, but also phenotypic plasticity during host plant selection can vary between populations. We further found that the populations responded differently to larval diet for some performance traits. However, it was only the Italian population that showed indications of any link between preference and performance, as they had slower development on their least preferred host plant. Overall, preference divergence between populations seems not to be driven by local variation in larval performance

Challenges and opportunities for increasing the use of low-risk plant protection products in sustainable production. A review

Plant production systems worldwide are struggling to meet the diverse and increasing needs of humankind while also facing challenges such as climate change and biodiversity loss. This, combined with the desirable transition from the use of conventional pesticides to more sustainable plant protection solutions, has led to an urgent, and increasing, need for low-risk plant protection products (PPPs) to be developed, applied, and integrated into management practices across all types of plant production systems. Despite a high demand from end users and consumers together with joint political goals at the EU level to replace conventional pesticides, the number of low-risk PPPs on the European market remains low, in comparison to synthetic agrochemicals. In this review, we summarize knowledge about the policy, technical, and administrative issues hampering the process of bringing new low-risk PPPs to the European market. We present an overview of the challenges in using the low-risk PPPs that are currently available within the EU agricultural, horticultural, and forestry sectors. We describe the variation in modes of action and the limitations associated with different application techniques and give concrete examples of problems and solutions from Swedish plant production sectors, in contrast to global perspectives as demonstrated by examples from African agriculture. Finally, we conclude that trans-sectoral, multi-actor approaches are required and provide suggestions on how to address the remaining knowledge gaps related to efficiency, application, and economics of low-risk PPP use in Integrated Pest Management (IPM) solutions for plant protection to improve future food security in Europe

Harnessing nature-based solutions for smallholder plant health in a changing climate

The impacts of climate change on resource-poor farmers are especially severe and include increased challenges with food security and food safety. This report explores how linking the frameworks of nature-based solutions, integrated pest management (IPM), and One Health can facilitate the design of climate-resilient plant health systems, with particular benefits for reduced pesticide use and exposure. Climate-smart approaches to IPM are proposed as a means to reduce emerging risks from pest insects, nematodes, weeds, and diseases under climate change. We elaborate the main climate change threats – and adaptation options – for five key nature-based solutions central to IPM: host plant resistance and tolerance, habitat manipulation, biological control, semiochemical control, and the use of biopesticides. We conclude by laying out a road map for ‘climate-smart IPM’, which outlines the types of support required for practical implementation, such as climate-informed advisory services, information and communication technology, and policy. While emphasis throughout is placed on smallholder production systems – particularly for sub-Saharan Africa – the principles of climate-smart IPM can be considered relevant to crop production generally

Effect of angiotensin-converting enzyme inhibitor and angiotensin receptor blocker initiation on organ support-free days in patients hospitalized with COVID-19

IMPORTANCE Overactivation of the renin-angiotensin system (RAS) may contribute to poor clinical outcomes in patients with COVID-19. Objective To determine whether angiotensin-converting enzyme (ACE) inhibitor or angiotensin receptor blocker (ARB) initiation improves outcomes in patients hospitalized for COVID-19. DESIGN, SETTING, AND PARTICIPANTS In an ongoing, adaptive platform randomized clinical trial, 721 critically ill and 58 non–critically ill hospitalized adults were randomized to receive an RAS inhibitor or control between March 16, 2021, and February 25, 2022, at 69 sites in 7 countries (final follow-up on June 1, 2022). INTERVENTIONS Patients were randomized to receive open-label initiation of an ACE inhibitor (n = 257), ARB (n = 248), ARB in combination with DMX-200 (a chemokine receptor-2 inhibitor; n = 10), or no RAS inhibitor (control; n = 264) for up to 10 days. MAIN OUTCOMES AND MEASURES The primary outcome was organ support–free days, a composite of hospital survival and days alive without cardiovascular or respiratory organ support through 21 days. The primary analysis was a bayesian cumulative logistic model. Odds ratios (ORs) greater than 1 represent improved outcomes. RESULTS On February 25, 2022, enrollment was discontinued due to safety concerns. Among 679 critically ill patients with available primary outcome data, the median age was 56 years and 239 participants (35.2%) were women. Median (IQR) organ support–free days among critically ill patients was 10 (–1 to 16) in the ACE inhibitor group (n = 231), 8 (–1 to 17) in the ARB group (n = 217), and 12 (0 to 17) in the control group (n = 231) (median adjusted odds ratios of 0.77 [95% bayesian credible interval, 0.58-1.06] for improvement for ACE inhibitor and 0.76 [95% credible interval, 0.56-1.05] for ARB compared with control). The posterior probabilities that ACE inhibitors and ARBs worsened organ support–free days compared with control were 94.9% and 95.4%, respectively. Hospital survival occurred in 166 of 231 critically ill participants (71.9%) in the ACE inhibitor group, 152 of 217 (70.0%) in the ARB group, and 182 of 231 (78.8%) in the control group (posterior probabilities that ACE inhibitor and ARB worsened hospital survival compared with control were 95.3% and 98.1%, respectively). CONCLUSIONS AND RELEVANCE In this trial, among critically ill adults with COVID-19, initiation of an ACE inhibitor or ARB did not improve, and likely worsened, clinical outcomes. TRIAL REGISTRATION ClinicalTrials.gov Identifier: NCT0273570

Långliggande fältförsök för rot- och knölväxter – behov och möjligheter identifierade genom intervjuer

I den här rapporten presenteras en utredning om behov och möjligheter för långliggande fältförsök för rot- och knölgrödor. Utredningen baseras huvudsakligen på intervjuer med representanter från universitet, näring, rådgivning och finansiärer, och även på en mindre uppföljande enkät till de intervjuade. Intervjuerna visar på att det finns ett brett intresse av långliggande fältförsök med frågeställningar som explicit rör rot- och knölgrödor. Frågeställningar som anses särskilt viktiga rör markbearbetning, växtskydd och växtföljd men även andra aspekter föreslås. Det finns ett intresse av att samarbeta om den här typen av försök men för många aktörer är det viktigt att man då kan få ut även kortsiktigare resultat och att dessa ska vara användbara för organisationen. Den främsta utmaningen kan vara att säkra långsiktig finansiering men även experimentdesign och organisation runt försöken är viktiga att beakta för att de ska ha ett långsiktigt värde