Chemical Composition of Piper nigrum L. Cultivar Guajarina Essential Oils and Their Biological Activity.

The essential oils and aroma derived from the leaves (L), stems (St), and spikes (s) of Piper nigrum L. cv. Guajarina were extracted; the essential oils were extracted using hydrodistillation (HD), and steam distillation (SD), and the aroma was obtained by simultaneous distillation and extraction (SDE). Chemical constituents were identified and quantified using GC/MS and GC-FID. Preliminary biological activity was assessed by determining the toxicity against Artemia salina Leach larvae, calculating mortality rates, and determining lethal concentration values (LC50). The predominant compounds in essential oil samples included α-pinene (0-5.6%), ß-pinene (0-22.7%), limonene (0-19.3%), 35 linalool (0-5.3%), δ-elemene (0-10.1%), ß-caryophyllene (0.5-21.9%), γ-elemene (7.5-33.9%), and curzerene (6.9-31.7%). Multivariate analysis, employing principal component analysis (PCA) and hierarchical cluster analysis (HCA), revealed three groups among the identified classes and two groups among individual compounds. The highest antioxidant activity was found for essential oils derived from the leaves (167.9 41 mg TE mL-1). Larvicidal potential against A. salina was observed in essential oils obtained from the leaves (LC50 6.40 µg mL-1) and spikes (LC50 6.44 µg mL-1). The in silico studies demonstrated that the main compounds can interact with acetylcholinesterase, thus showing the potential molecular interaction responsible for the toxicity of the essential oil in A. salina.

The functional microclimate of an urban arthropod pest: Urban heat island temperatures in webs of the western black widow spider.

Urbanization alters natural landscapes and creates unique challenges for urban wildlife. Similarly, the Urban Heat Island (UHI) effect can produce significantly elevated temperatures in urban areas, and we have a relatively poor understanding of how this will impact urban biodiversity. In particular, most studies quantify the UHI using broad-scale climate data rather than assessing microclimate temperatures actually experienced by organisms. In addition, studies often fail to address spatial and temporal complexities of the UHI. Here we examine the thermal microclimate and UHI experienced in the web of Western black widow spiders (Latrodectus hesperus), a medically-important, superabundant urban pest species found in cities across the Western region of North America. We do this using replicate urban and desert populations across an entire year to account for seasonal variation in the UHI, both within and between habitats. Our findings reveal a strong nighttime, but no daytime, UHI effect, with urban spider webs being 2-5 °C warmer than desert webs at night. This UHI effect is most prominent during the spring and least prominent in winter, suggesting that the UHI need not be most pronounced when temperatures are most elevated. Urban web temperatures varied among urban sites in the daytime, whereas desert web temperatures varied among desert sites in the nighttime. Finally, web temperature was significantly positively correlated with a spider's boldness, but showed no relationship with voracity towards prey, web size, or body condition. Understanding the complexities of each organism's thermal challenges, the "functional microclimate", is crucial for predicting the impacts of urbanization and climate change on urban biodiversity and ecosystem functioning.

Rainforest transformation reallocates energy from green to brown food webs.

Terrestrial animal biodiversity is increasingly being lost because of land-use change1,2. However, functional and energetic consequences aboveground and belowground and across trophic levels in megadiverse tropical ecosystems remain largely unknown. To fill this gap, we assessed changes in energy fluxes across 'green' aboveground (canopy arthropods and birds) and 'brown' belowground (soil arthropods and earthworms) animal food webs in tropical rainforests and plantations in Sumatra, Indonesia. Our results showed that most of the energy in rainforests is channelled to the belowground animal food web. Oil palm and rubber plantations had similar or, in the case of rubber agroforest, higher total animal energy fluxes compared to rainforest but the key energetic nodes were distinctly different: in rainforest more than 90% of the total animal energy flux was channelled by arthropods in soil and canopy, whereas in plantations more than 50% of the energy was allocated to annelids (earthworms). Land-use change led to a consistent decline in multitrophic energy flux aboveground, whereas belowground food webs responded with reduced energy flux to higher trophic levels, down to -90%, and with shifts from slow (fungal) to fast (bacterial) energy channels and from faeces production towards consumption of soil organic matter. This coincides with previously reported soil carbon stock depletion3. Here we show that well-documented animal biodiversity declines with tropical land-use change4-6 are associated with vast energetic and functional restructuring in food webs across aboveground and belowground ecosystem compartments.

Plants in the rearing of arthropod predators and parasitoids: benefits, constraints, and alternatives.

This review explores the roles of plants in rearing systems for arthropod biological control agents, addressing benefits and drawbacks. The utilization of plant materials in mass rearing processes for predators and parasitoids serves various purposes. Natural rearing systems require plants for cultivating hosts or prey. Whereas these rearing systems can be economically viable, they also have important practical limitations. Alternative rearing strategies make use of plant components as sources of moisture or nutrients, and as living or oviposition substrates. Plant-derived foods, such as honey and pollen, can be used as stand-alone foods for the rearing of several omnivorous parasitoids and predators. Certain omnivorous predators show enhanced life table parameters when suboptimal food is supplemented with plant materials. However, the integration of plants into rearing systems introduces complexities that challenge their efficiency, as plant defenses and contaminants can impact natural enemy fitness. Therefore, alternatives to plant foods or substrates in the rearing environment are discussed.

A broad-taxa approach as an important concept in ecotoxicological studies and pollution monitoring.

Aquatic invertebrates play a pivotal role in (eco)toxicological assessments because they offer ethical, cost-effective and repeatable testing options. Additionally, their significance in the food chain and their ability to represent diverse aquatic ecosystems make them valuable subjects for (eco)toxicological studies. To ensure consistency and comparability across studies, international (eco)toxicology guidelines have been used to establish standardised methods and protocols for data collection, analysis and interpretation. However, the current standardised protocols primarily focus on a limited number of aquatic invertebrate species, mainly from Arthropoda, Mollusca and Annelida. These protocols are suitable for basic toxicity screening, effectively assessing the immediate and severe effects of toxic substances on organisms. For more comprehensive and ecologically relevant assessments, particularly those addressing long-term effects and ecosystem-wide impacts, we recommended the use of a broader diversity of species, since the present choice of taxa exacerbates the limited scope of basic ecotoxicological studies. This review provides a comprehensive overview of (eco)toxicological studies, focusing on major aquatic invertebrate taxa and how they are used to assess the impact of chemicals in diverse aquatic environments. The present work supports the use of a broad-taxa approach in basic environmental assessments, as it better represents the natural populations inhabiting various ecosystems. Advances in omics and other biochemical and computational techniques make the broad-taxa approach more feasible, enabling mechanistic studies on non-model organisms. By combining these approaches with in vitro techniques together with the broad-taxa approach, researchers can gain insights into less-explored impacts of pollution, such as changes in population diversity, the development of tolerance and transgenerational inheritance of pollution responses, the impact on organism phenotypic plasticity, biological invasion outcomes, social behaviour changes, metabolome changes, regeneration phenomena, disease susceptibility and tissue pathologies. This review also emphasises the need for harmonised data-reporting standards and minimum annotation checklists to ensure that research results are findable, accessible, interoperable and reusable (FAIR), maximising the use and reusability of data. The ultimate goal is to encourage integrated and holistic problem-focused collaboration between diverse scientific disciplines, international standardisation organisations and decision-making bodies, with a focus on transdisciplinary knowledge co-production for the One-Health approach.

Transcriptome analysis of a springtail, Folsomia candida, reveals energy constraint and oxidative stress during petroleum hydrocarbon exposure.

Petroleum hydrocarbon (PHC) contamination in soil is ubiquitous and poses harmful consequences to many organisms. The toxicity of PHC-impacted soil is difficult to predict due to variations in mixture composition and the impacts of natural weathering processes. Hence, high-throughput methods to assess PHC-impacted soils is required to expedite land management decisions. Next-generation sequencing is a robust tool that allows researchers to investigate the effects of contaminants on the transcriptome of organisms and identify molecular biomarkers. In this study, the effects of PHCs on conventional endpoints (i.e., survival and reproduction) and gene expression rates of a model springtail species, Folsomia candida were investigated. Age-synchronized F. candida were exposed to ecologically-relevant concentrations of soils spiked with fresh crude oil to calculate the reproductive EC25 and EC50 values using conventional toxicity testing. Soils spiked to these concentrations were then used to evaluate effects on the F. candida transcriptome over a 7-day exposure period. RNA-seq analysis found 98 and 132 differentially expressed genes when compared to the control for the EC25 and EC50 treatment groups, respectively. The majority of up-regulated genes were related to xenobiotic biotransformation reactions and oxidative stress response, while down-regulated genes coded for carbohydrate and peptide metabolic processes. Promotion of the pentose phosphate pathway was also found. Results suggest that the decreased reproduction rates of F. candida exposed to PHCs is due to energy constraints caused by inhibition of carbohydrate metabolic processes and allocation of remaining energy to detoxify xenobiotics. These findings provide insights into the molecular effects in F. candida following exposure to crude oil for seven days and highlight their potential to be used as a high-throughput screening test for PHC-contaminated sites. Adverse molecular effects can be measured as early as 24 h following exposure, whereas conventional toxicity tests may require a minimum of four weeks.

Chemical and ecotoxicological indicators for evaluating the treatment of coal mining wastes.

This paper consists of the evaluation in regards to the ecotoxicological effectiveness of a treatment applied to a coal mining waste. The treatment consisted of separating the particles based on gravimetric concentration in spirals, generating three fractions: heavy, intermediate, and light, with high, moderate, and low pyrite content, respectively. The intermediate fraction represents the larger disposal volume of the waste on soils. To evaluate the effectiveness of the treatment, metal determination and bioassays Eisenia andrei, Folsomia candida, Lactuca sativa, Daphnia similis, and Raphidocelis subcapitata were applied to the intermediary fraction. To evaluate the toxicity to aquatic organisms, elutriates were generated from the unprocessed waste and the intermediate fraction. The intermediate fraction showed a decrease of metal concentrations compared to the untreated waste. Metal concentrations in the intermediate fraction were below the Brazilian thresholds for soil quality. Avoidance bioassay with E. andrei and germination tests of L. sativa showed no significant effects. The bioassay with F. candida indicated a significant reduction in reproduction at the highest doses used (24% and 50%). Bioassays with D. similis and R. subcapitata revealed a reduction in toxicity of the intermediate fraction compared to the untreated waste. However, the toxicity levels of the intermediate fraction to aquatic organisms still require attention, especially in regards to pH that played a crucial role in the toxicity. Finally, the results suggest that the treatment performed on the coal waste was efficient, even though significant toxicity have still been detected in the treated waste and additional steps are still required for adequate final disposal.

Copper-contaminated soil compromises thermal performance in the springtail Folsomia candida (Collembola).

The widespread agricultural and industrial emissions of copper-based chemicals have increased copper levels in soils worldwide. Copper contamination can cause a range of toxic effects on soil animals and influence thermal tolerance. However, toxic effects are commonly investigated using simple endpoints (e.g., mortality) and acute tests. Thus, how organisms respond to ecological realistic sub-lethal and chronic exposures across the entire thermal scope of an organism is not known. In this study, we investigated the effects of copper exposure on the thermal performance of a springtail (Folsomia candida), regarding its survival, individual growth, population growth, and the composition of membrane phospholipid fatty acids. Folsomia candida (Collembola) is a typical representative of soil arthropods and a model organism that has been widely used for ecotoxicological studies. In a full-factorial soil microcosm experiment, springtails were exposed to three levels of copper (ca. 17 (control), 436, and 1629 mg/kg dry soil) and ten temperatures from 0 to 30 °C. Results showed that three-week copper exposure at temperatures below 15 °C and above 26 °C negatively influenced the springtail survival. The body growth was significantly lower for the springtails in high-dose copper soils at temperatures above 24 °C. A high copper level reduced the number of juveniles by 50 %, thereby impairing population growth. Both temperature and copper exposure significantly impacted membrane properties. Our results indicated that high-dose copper exposure compromised the tolerance to suboptimal temperatures and decreased maximal performance, whereas medium copper exposure partially reduced the performance at suboptimal temperatures. Overall, copper contamination reduced the thermal tolerance of springtails at suboptimal temperatures, probably by interfering with membrane homeoviscous adaptation. Our results show that soil organisms living in copper-contaminated areas might be more sensitive to thermally stressful periods.

Can species naming drive scientific attention? A perspective from plant-feeding arthropods.

How do researchers choose their study species? Some choices are based on ecological or economic importance, some on ease of study, some on tradition-but could the name of a species influence researcher decisions? We asked whether phytophagous arthropod species named after their host plants were more likely to be assayed for host-associated genetic differentiation (or 'HAD'; the evolution of cryptic, genetically isolated host specialists within an apparently more generalist lineage). We chose 30 arthropod species (from a Google Scholar search) for which a HAD hypothesis has been tested. We traced the etymologies of species names in the 30 corresponding genera, and asked whether HAD tests were more frequent among species whose etymologies were based on host-plant names (e.g. Eurosta solidaginis, which attacks Solidago) versus those with other etymologies (e.g. Eurosta fenestrata, from Latin fenestra, 'window'). Species with host-derived etymologies were more likely to feature in studies of HAD than those with other etymologies. We speculate that the etymology of a scientific name can draw a researcher's attention to aspects of life-history and thus influence the direction of our scientific gaze.

Safe Removal of a Centipede From the Ear By Using an Innovative Practicable Method: A Case Report.

Arthropods may become lodged inside the ear and cause considerable emotional and physical trauma. Cases of centipedes being lodged in the external auditory canal have rarely been reported. In this article, we present the case of woman who had a centipede lodged inside her right external auditory canal. Removal using a topical local anesthetic can lead to vigorous activity of the centipede, which can cause harm to the patient and clinicians. Therefore, we developed and successfully applied a practicable method that involved using a modified plastic bottle for safe centipede removal. In conclusion, centipedes can express distinct and threatening behavior, and clinicians should pay attention to the activity of the lodged centipede and possibly use the proposed method to safely remove it.

Three first records of stick insects attacking plants (Inseect: Phasmida) in Tibet / Três primeiros registros de insetos-pau atacando plantas (Inseect: Phasmida) no Tibet

Except for a few stick insects that are economically valuable, most species be considered to be forest pests, so it is extremely important to obtain plant host-use information of more stick insects. In this paper, the plant hosts of three species of stick insects were recorded for the first time. We also discovered these stick insects can feed upon the flowers or leaves of plants. Lopaphus unidentatus (Chen & He, 1995) (Phasmida: Lonchodidae) attacked Hypericum choisianum Wall. ex N. Robson, 1973 (Hypericaceae), Leurophasma dolichocercum Bi, 1995 (Phasmida: Aschiphasmatidae) attacked Antenoron filiforme (Thunb.) Roberty & Vautier, 1964 (Polygonaceae) and Megalophasma granulatum Bi, 1995 (Phasmida: Lonchodidae) attacked Debregeasia orientalis C. J. Chen, 1991 (Urticaceae). Finally, we were lucky enough to also obtain photographs of them mating and feeding.

Exceto por alguns insetos-pau que são economicamente valiosos, a maioria das espécies pode ser considerada praga florestal, por isso é extremamente importante obter informações sobre o uso de hospedeiros de plantas de mais insetos-pau. Neste artigo, as plantas hospedeiras de três espécies de bicho-pau foram registradas pela primeira vez. Também descobrimos que esses bichos-pau podem se alimentar de flores ou folhas de plantas. Lopaphus unidentatus (Chen & He, 1995) (Phasmida: Lonchodidae) atacou a parede de Hypericum choisianum. ex N. Robson, 1973 (Hypericaceae), Leurophasma dolichocercum Bi, 1995 (Phasmida: Aschiphasmatidae) atacou Antenoron filiforme (Thunb.) Roberty & Vautier, 1964 (Polygonaceae) e Megalophasma granulatum Bi, 1995 (Phasmida: Lonchodidae orientaled) atacou Chen, 1991 (Urticaceae). Finalmente, tivemos a sorte de também obter fotos deles se acasalando e se alimentando.

[Response of soil Collembola to nitrogen and phosphorus deposition: A review]. / åœŸå£¤è·³è™«å¯¹æ°®ç£·å »åˆ†å“åº”çš„ç ”ç©¶è¿›å±•.

Collembola are among the most abundant and integral group in soil decomposers. They channel C and nutrients from basic food resources to higher trophic levels, and therefore play an irreplaceable role in the underground food web. Collembola community would be altered dramatically by increasing N and P deposition. However, we still know little about how Collembola respond to N and P inputs, which will largely retard our steps to understand the ecological functions of collembolans, material circulation and energy flow of the underground food web, and even C cycling in terrestrial ecosystem. The different classification rules for Collembola functional groups have led to poor comparability of research results in the literature. This review proposed three taxonomic criteria of Collembola and four common research means on trophic relationships, summarized the mechanisms underlying the responses of Collembola to N and P addition alone and coadded. Overall, Collembola generally shows a negative response to N addition namely community density decreases, while a positive response to P addition in most ecosystems. The situation was more complicated under the combined N and P application. In the future, the research of Collembola response to N and P deposition should focus on the scientific taxa of Collembola functional groups, improving the research methods of trophic structure of Collembola, and the mechanism underlying the impacts of N and P interaction on Collembola community.

Influence of Turfgrass Parameters on the Abundance of Arthropods in Sod Farms.

Sod farms, where turfgrass is commercially produced, have a unique system, in which sod is harvested within 2 yr after planting. Understanding the turfgrass factors that influence the abundance of predators, herbivores, detritivores, and parasitoids that inhabit turfgrass paves the foundation for developing effective pest management programs. However, little is known about those factors in sod farms. The objective of the study was to determine the influence of turfgrass height, density, and thatch thickness on abundance of arthropod taxa in sod farms. The study was conducted at 18 and 10 sod field sites in 2019 and 2020, respectively. Four pitfall traps were deployed at each site. In 2019, each site was sampled in May, June, and July, whereas in 2020, each site was sampled in June and August. In 2019, the numbers of predatory heteropterans were two times greater in bermudagrass (Cynodon dactylon L.) than in zoysiagrass (Zoysia spp.). The numbers of predatory mirids, Spanogonicus albofasciatus (Reuter), and carabids significantly decreased with increases in turfgrass height. In 2020, the abundance of staphylinids increased as the thatch thickness increased. The abundance of Sphenophorus spp. adults were significantly greater in bermudagrass than in zoysiagrass in 2020 and were more abundant in the denser turfgrasses in both years. The predatory arthropods were positively correlated with increased densities of cicadellids, whereas predatory mirids were positively associated with cicadellids, delphacids, and chrysomelids. These results have implications on management of arthropod pests in sod farms as abundance of beneficial arthropods are influenced by turfgrass factors.

Insectivorous birds reduce herbivory but do not increase mangrove growth across productivity zones.

Top-down effects of predators and bottom-up effects of resources are important drivers of community structure and function in a wide array of ecosystems. Fertilization experiments impose variation in resource availability that can mediate the strength of predator impacts, but the prevalence of such interactions across natural productivity gradients is less clear. We studied the joint impacts of top-down and bottom-up factors in a tropical mangrove forest system, leveraging fine-grained patchiness in resource availability and primary productivity on coastal cays of Belize. We excluded birds from canopies of red mangrove (Rhizophoraceae: Rhizophora mangle) for 13 months in zones of phosphorus-limited, stunted dwarf mangroves, and in adjacent zones of vigorous mangroves that receive detrital subsidies. Birds decreased total arthropod densities by 62%, herbivore densities more than fivefold, and reduced rates of leaf and bud herbivory by 45% and 52%, respectively. Despite similar arthropod densities across both zones of productivity, leaf and bud damage were 2.0 and 4.3 times greater in productive stands. Detrital subsidies strongly impacted a suite of plant traits in productive stands, potentially making leaves more nutritious and vulnerable to damage. Despite consistently strong impacts on herbivory, we did not detect top-down forcing that impacted mangrove growth, which was similar with and without birds. Our results indicated that both top-down and bottom-up forces drive arthropod community dynamics, but attenuation at the plant-herbivore interface weakens top-down control by avian insectivores.

[Effects of cultivating Coptis chinensis and Paris polyphylla on soil microarthropod communities.] / 种植黄连和重楼对小型土壤节肢动物群落的影响.

In recent years, the area of herbal medicine planting is rapidly increasing. The effects of planting herbal medicines on soil invertebrate communities are still unclear. To reveal the effects of planting different herbal medicines on the soil microarthropod communities, soil microarthropods in two fields of planting Coptis chinensis and Paris polyphylla for 3-year and 5-year, respectively, were investigated in Pengzhou, Chengdu in July 2020. A total of 526 individuals of soil microarthropods were recorded and classified into 4 classes, 17 orders, 69 families, and 98 genera or taxonomic groups. The communities were dominated by Isotoma, Piatynothrus, Folsomia, and Paranura. The community structure of soil microarthropods differed obviously among the two herbal medicine fields, with the main influencing taxonomic groups of Proisotoma, Ocesobates and Epicridae. The total taxonomic group richness of soil microarthropods were richer in C. chinensis field than P. polyphylla field. There was no significant difference in the abundance and diversity index between the two fields. With the increases of cultivating years, the abundance of soil microarthropods in C. chinensis field declined significantly, and Shannon index increased significantly in P. polyphylla field. The redundancy analysis showed that the community structure of soil microarthropods was mainly affected by soil available N, pH, total K, and available K. It suggested that the effects of cultivating herbal medicines on soil microarthropod communities differed between herbal medicine species. Therefore, we recommended to intercrop C. chinensis and P. polyphylla for maintaining the stability of soil microarthropod diversity and promoting ecosystem function.

Alternative prey and farming system mediate predation of Colorado potato beetles by generalists.

BACKGROUND: Biological control by generalist predators can be mediated by the abundance and biodiversity of alternative prey. When alternative prey draw predator attacks away from the control target, they can weaken pest suppression. In other cases, a diverse prey base can promote predator abundance and biodiversity, reduce predator-predator interference, and benefit biocontrol. Here, we used molecular gut-content analysis to assess how community composition altered predation of Colorado potato beetle (Leptinotarsa decemlineata (Say)) by Nabis sp. and Geocoris sp. Predators were collected from organic or conventional potato (Solanum tuberosum L.) fields, encouraging differences in arthropod community composition. RESULTS: In organic fields, Nabis predation of potato beetles decreased with increasing arthropod richness and predator abundance. This is consistent with Nabis predators switching to other prey species when available and with growing predator-predator interference. In conventional fields these patterns were reversed, however, with potato beetle predation by Nabis increasing with greater arthropod richness and predator abundance. For Geocoris, Colorado potato beetle predation was more frequent in organic than in conventional fields. However, Geocoris predation of beetles was less frequent in fields with higher abundance of the detritus-feeding fly Scaptomyza pallida Zetterstedt, or of all arthropods, consistent with predators choosing other prey when available. CONCLUSION: Alternative prey generally dampened predation of potato beetles, suggesting these pests were less-preferred prey. Nabis and Geocoris differed in which alternative prey were most disruptive to feeding on potato beetles, and in the effects of farm management on predation, consistent with the two predator species occupying complementary feeding niches. © 2021 Society of Chemical Industry.

In vitro acaricidal activity of essential oil and crude extracts of Laurus nobilis, (Lauraceae) grown in Tunisia, against arthropod ectoparasites of livestock and poultry: Hyalomma scupense and Dermanyssus gallinae.

The current study assayed the toxicity of Laurus nobilis essential oil and crude extracts obtained using solvents of increasing polarity (cyclohexane, acetone and ethanol), on two ectoparasites of veterinary importance, i.e., Hyalomma scupense and Dermanyssus gallinae. The major components detected in bay laurel essential oil were dominated by 1.8-cineole (46.56 %), α-terpinenyl acetate (13.99 %), sabinene (7.69), α-pinene (5.75), linalool (5.50), methyleugenol (5.36 %) and ß-pinene (3.97). The highest total phenolic and flavonoids contents were present in the ethalonic extract of L. nobilis leaves at an amount of 152.88 mg gallic acid equivalents per gram of dry weight (GAE/g DW) and 21.77 mg quercetin equivalent per gram of dry weight (QE/g DW), respectively. In vitro acaricidal effects of essensial oil and crude extract of L. nobilis against H. scupense were ascertained by adult immersion test of engorged females (AIT) and larval packet test (LPT) compared with a reference drug amitraz. The essential oil exhibited strong acaricidal activity against tick engorged female and inhibition of hatching eggs. After 24 h of exposure, at the highest tested concentration (100 mg/mL) essential oil induced 90.67 % mortality of H. scupense larvae (LC50 = 10.69 mg/mL). Otherwise, essential oil exhibited high acaricidal activity compared to extracts, and among the extract, the ethanolic extract revealed the highest acaricidal efficacy (81.27 % female mortality). Results from mite contact toxicity showed that essential oil and extracts from L. nobilis were toxic to D. gallinae. Bay essential oil was both more toxic to mites, and faster in exerting this toxicity than other tested crude extracts. L. nobilis essential oil concentration leaded to enhance mortality of D. gallinae reaching the highest (100 %) mortality at 12 h with a concentration of 320 mg/mL. While, ethanolic extract acheived this rate after 24 h of exposure at same concentration. Cyclohexanic extract showed weak acaricidal activity.

Climatic displacement exacerbates the negative impact of drought on plant performance and associated arthropod abundance.

Climate change is acting on species and modifying communities and ecosystems through changes not only with respect to mean abiotic conditions, but also through increases in the frequency and severity of extreme events. Changes in mean aridity associated with climate change can generate ecotype by environment mismatch (i.e., climatic displacement). At the same time, variability around these shifting means is predicted to increase, resulting in more extreme droughts. We characterized the effects of two axes of climate change, climatic displacement and drought, on the shrub Artemisia californica and its arthropods. We established common gardens of plants sourced along an aridity gradient (3.5-fold variation in mean annual precipitation) in an arid region of the species distribution, thus generating a gradient of climatic displacement (sustained increase in aridity) as predicted with climate change. We surveyed plants and arthropods over eight years where precipitation varied sixfold, including both extreme drought and relatively mesic conditions. These two axes of climate change interacted to influence plant performance, such that climatically displaced populations grew slowly regardless of drought and suffered substantial mortality during drought years. Conversely, local populations grew quickly, increased growth during wet years, and had low mortality regardless of drought. Effects on plant annual arthropod yield were negative and additive, with drought effects exceeding that of climatic displacement by 24%. However, for plant lifetime arthropod yield, incorporating effects on both plant growth and survival, climatic displacement exacerbated the negative effects of drought. Collectively these results demonstrate how climatic displacement (through increasing aridity stress) strengthens the negative effects of drought on plants and, indirectly, on arthropods, suggesting the possibility of climate-mediated trophic collapse.

Introgression of the sesquiterpene biosynthesis from Solanum habrochaites to cultivated tomato offers insights into trichome morphology and arthropod resistance.

MAIN CONCLUSION: Cultivated tomatoes harboring the plastid-derived sesquiterpenes from S. habrochaites have altered type-VI trichome morphology and unveil additional genetic components necessary for piercing-sucking pest resistance. Arthropod resistance in the tomato wild relative Solanum habrochaites LA1777 is linked to specific sesquiterpene biosynthesis. The Sesquiterpene synthase 2 (SsT2) gene cluster on LA1777 chromosome 8 controls plastid-derived sesquiterpene synthesis. The main genes at SsT2 are Z-prenyltransferase (zFPS) and Santalene and Bergamotene Synthase (SBS), which produce α-santalene, ß-bergamotene, and α-bergamotene in LA1777 round-shaped type-VI glandular trichomes. Cultivated tomatoes have mushroom-shaped type-VI trichomes with much smaller glands that contain low levels of monoterpenes and cytosolic-derived sesquiterpenes, not presenting the same pest resistance as in LA1777. We successfully transferred zFPS and SBS from LA1777 to cultivated tomato (cv. Micro-Tom, MT) by a backcrossing approach. The trichomes of the MT-Sst2 introgressed line produced high levels of the plastid-derived sesquiterpenes. The type-VI trichome internal storage-cavity size increased in MT-Sst2, probably as an effect of the increased amount of sesquiterpenes, although it was not enough to mimic the round-shaped LA1777 trichomes. The presence of high amounts of plastid-derived sesquiterpenes was also not sufficient to confer resistance to various tomato piercing-sucking pests, indicating that the effect of the sesquiterpenes found in the wild S. habrochaites can be insect specific. Our results provide for a better understanding of the morphology of S. habrochaites type-VI trichomes and paves the way to obtain insect-resistant tomatoes.

Multidimensional trophic niche revealed by complementary approaches: Gut content, digestive enzymes, fatty acids and stable isotopes in Collembola.

Trophic niche differentiation may explain coexistence and shape functional roles of species. In complex natural food webs, however, trophic niche parameters depicted by single and isolated methods may simplify the multidimensional nature of consumer trophic niches, which includes feeding processes such as food choice, ingestion, digestion, assimilation and retention. Here we explore the correlation and complementarity of trophic niche parameters tackled by four complementary methodological approaches, that is, visual gut content, digestive enzyme, fatty acid and stable isotope analyses-each assessing one or few feeding processes, and demonstrate the power of method combination. Focusing on soil ecosystems, where many omnivore species with cryptic feeding habits coexist, we chose Collembola as an example. We compiled 15 key trophic niche parameters for 125 species from 40 studies. We assessed correlations among trophic niche parameters and described variation of these parameters in different Collembola species, families and across life-forms, which represent microhabitat specialisation. Correlation between trophic niche parameters was weak in 45 out of 64 pairwise comparisons, pointing at complementarity of the four methods. Jointly, the results indicated that fungal- and plant-feeding Collembola assimilate storage, rather than structural polysaccharides, and suggested bacterial feeding as a potential alternative feeding strategy. Gut content and fatty acid analyses suggested alignment between ingestion and assimilation/retention processes in fungal- and plant-feeding Collembola. From the 15 trophic niche parameters, six were related to Collembola family identity, suggesting that not all trophic niche dimensions are phylogenetically structured. Only three parameters were related to the life-forms, suggesting that species use various feeding strategies when living in the same microenvironments. Consumers can meet their nutritional needs by varying their food choices, ingestion and digestion strategies, with the connection among different feeding processes being dependent on the consumed resource and consumer adaptations. Multiple methods reveal different dimensions, together drawing a comprehensive picture of the trophic niche. Future studies applying the multidimensional trophic niche approach will allow us to trace trophic complexity and reveal niche partitioning of omnivorous species and their functional roles, especially in cryptic environments such as soils, caves, deep ocean or benthic ecosystems.