Entomologia Experimentalis et Applicata最新文献

Light-emitting diode traps in commercial greenhouses: A field study report on Encarsia formosa bycatch—B. Grupe & R. Meyhöfer (https://doi.org/10.1111/eea.13521).

The fall armyworm, Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae), is a highly destructive agricultural pest. The ability of S. frugiperda to survive and reproduce is widely recognized, but it is also important to consider the role of larval cannibalism as a significant biological trait. Understanding the cannibalistic habits of pests helps to explore the dynamics and evolution of their populations and facilitates the monitoring of insect outbreaks. Therefore, the stages, densities, and intensity of cannibalism in S. frugiperda larvae, as well as the consequences for their development, were investigated under laboratory conditions. Spodoptera frugiperda larvae showed obvious cannibalism after the third instar even in the presence of maize (Zea mays L., Poaceae) leaves; cannibalism was not observed in first instars. In the case of only one cannibal, the percentage of prey consumed by cannibalism decreased with higher prey density, and the predatory functional responses of fourth- to sixth-instar predators to first- to third-instar preys were fitted using the Holling II model. Compared with larvae feeding on maize only, larvae feeding on a diet of maize supplemented with third-instar conspecifics had a longer developmental duration and a higher body weight, with no significant differences in larval survival, pupation, or eclosion rates. Larvae supplied with conspecifics only, in the absence of maize leaves, generally had a lower body weight than larvae supplied with maize only, although developmental duration was still longer, and longevity and fecundity rates were lower for these larvae. Overall, consuming a small quantity of conspecifics in addition to maize leaves prolonged the developmental duration of larvae and pupae to some extent, increased the body weight, and did not impact the longevity or reproduction of S. frugiperda. However, cannibalism only, without access to maize leaves, had a detrimental effect on adult longevity and reproduction. These findings could serve as a valuable reference for studying the life history of insects that consume agricultural crops and may have potential applications for biological control.

Yellow sticky traps (YSTs) are a standard tool for insect monitoring in greenhouses. These traps have been further developed by using them in combination with green light-emitting diodes (LEDs) to increase their attractiveness towards pest insects such as aphids and whiteflies. However, also natural enemies, such as the whitefly parasitoid Encarsia formosa Gahan (Hymenoptera: Aphelinidae), are attracted to these traps. This may cause problems with biological control of the pest or may be used for indirect monitoring purposes. Therefore, we compared the attractiveness of YSTs and green (521 nm) LED traps towards E. formosa under practical growing conditions in tomato, Solanum lycopersicum L. (Solanaceae) and cucumber, Cucumis sativus L. (Cucurbitaceae), crops in the greenhouse. The aim of the study was to investigate the compatibility of LED traps with this parasitoid frequently used against the greenhouse whitefly, Trialeurodes vaporariorum Westwood (Hemiptera: Aleyrodidae). The results show LED traps catching less E. formosa than standard YSTs. Moreover, LED traps also showed compatibility with other beneficial insects. The results are discussed in the context of the parasitoid's behaviour towards various green light spectra and in the context of pest and beneficial insect monitoring using different trap types. Our study will help implementing green LED traps in future insect monitoring programmes and developing new pest control strategies without affecting natural enemies.

Biotremology, officially coined in 2016, has rapidly emerged as a distinct scientific discipline, focusing on the study of substrate-borne mechanical waves in animal communication, particularly among insects. Initially seen as a niche within bioacoustics, biotremology is now recognized for its broad significance, rivalling chemical communication in its prevalence. This special issue highlights the multidisciplinary nature of biotremology, with research spanning insect behaviour, ecology and pest management. Studies showcase advances in understanding vibrational communication across diverse insect taxa, the development of new tools for reliable playback experiments and the growing potential of biotremology in applied pest control. This collection provides a snapshot of a dynamic field in rapid expansion, pushing the boundaries of both fundamental research and practical applications.

Communication is fundamental in the animal kingdom, essential to interactions such as mating, defense, and parental care. Vibrational communication has often been overlooked in the past, but in recent decades, it has become clear that insects use substrate vibrations as a communication signal. In burying beetles of the genus Nicrophorus, which are known for their biparental brood care, both parents stridulate. Spending a considerable period of their lives underground, it is very likely the beetles utilize vibrations as part of their communication system. As playback experiments are challenging with this species, this study looked at the physical propagation of the signal of Nicrophorus vespilloides Herbst (Coleoptera: Siliphidae) through three soil types, as well as behavior, to see whether vibrational communication is possible. The aims were to determine: (1) whether the soils used in the laboratory compare to soil from the field, (2) whether the distance of propagation is enough for the range the beetles cover during brood care, (3) whether the two sexes show a difference in stridulation likelihood, (4) whether propagation of defensive signals differs from brood care signals, and (5) whether we can determine a behavior during stridulations that shows a clear and useable reaction to the signal. We manipulated beetles to induce stridulation and then used laser Doppler vibrometers to record the signals using three substrates and various distances, alongside behavioral observations. We showed that the three substrates tested, peat, coconut coir, and forest soil, displayed differences in terms of vibrational propagation, and that burying beetle stridulation signals can be transmitted up to about 25 cm in the soil. We also showed that the location where the animals stridulate exerts a significant influence on the total duration and number of stridulations. Overall, vibrational communication is in principle conceivable in this species, as the signals are transmitted far enough in the natural substrate to allow complex communication, opening possibilities for vibrational communication during this biparental brood care.

Impacts of assisted migration: an introduced herbivore has short-term and long-term effects on its native host plant population—N. Ravikanthachari, L. L. Burch, R. E. Powell, D. M. Scott, C. R. Wayne, et al. (https://doi.org/10.1111/eea.13507).

Diatraea saccharalis Fabricius (Lepidoptera: Crambidae), known as sugarcane borer, is the most damaging pest of sugarcane (Saccharum officinarum L., Poaceae) in northwestern Argentina and it causes significant losses in sugar and ethanol production. Currently, chemical and biological controls are used, along with host plant resistance, but there is a clear trend toward adoption of integrated pest management strategies. Considering the potential environmental and health risks associated with using agrochemicals, our study focuses on utilizing bioactive natural products, specifically plant secondary metabolites. Senecio rudbeckiaefolius Meyen & Walp (Asteraceae) is a perennial shrub found in southern Peru, Bolivia, and northwestern Argentina, valued for its use in traditional medicine. The main compounds of the genus Senecio are sesquiterpenes, with some species containing pyrrolizidine alkaloids (PAs), known for their harmful effects on herbivorous insects and vertebrates. Plant extracts exhibit several modes of action, encompassing confusion, feeding deterrence, growth regulation, insecticidal, and repellent effects. Our goal was to analyze the chemical composition of an ethanolic extract (EE) of S. rudbeckiaefolius and evaluate its lethal and sublethal effects on D. saccharalis larvae. We also investigated the potential target sites affected by the ingestion of an alkaloidal fraction from the EE (AFEE) through a midgut histological study. The main secondary metabolites identified were the PAs and phenolic compounds, with the highest concentrations found in the flowers and leaves. The majority of the PAs identified were senecionine and integerrimine. Toxicity bioassays were carried out with larvae fed on a diet supplemented with an EE of S. rudbeckiaefolius. Concentration-dependent mortality and a marked inhibition of larval growth were recorded. We described the midgut histological structure and compared it with that of AFEE-fed larvae. Various morphological changes were observed in the intestinal epithelium, especially an increase in the number of goblet cells and pronounced acidophilic secretion in the lumen. These results suggest that the EE of S. rudbeckiaefolius could be promising for D. saccharalis control.

Drought may impact plant–soil biotic interactions in ways that modify aboveground herbivore performance, but the outcomes of such biotic interactions under future climate are not yet clear. We performed a growth chamber experiment to assess how long-term, drought-driven changes in belowground communities influence plant growth and herbivore performance using a plant–soil feedback experimental framework. We focussed on two common pasture legumes—lucerne, Medicago sativa L., and white clover, Trifolium repens L. (both Fabaceae)—and foliar herbivores—cotton bollworm, Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae), and two-spotted spider mite, Tetranychus urticae Koch (Acari: Tetranychidae). Soil was collected from a field facility where rainfall had been manipulated for 6 years, focussing on treatments representing ambient rainfall and prolonged drought (50% reduction relative to ambient), to consider the effects of biological legacies mediated by the prolonged drought. All soils were sterilized and re-inoculated to establish the respective home (i.e. where a given plant is cultivated in its own soil) and away (i.e. where a given plant is cultivated in another species' soil) treatments in addition to a sterile control. We found that the relative growth rate (RGR) and relative consumption of larvae were significantly lower on lucerne grown in soil with ambient rainfall legacies conditioned by white clover. Conversely, the RGR of insect larvae was lower on white clover grown in soil with prolonged drought legacies conditioned by lucerne. Two-spotted spider mite populations and area damage (mm²) were significantly reduced on white clover grown in lucerne-conditioned soil in drought legacies. The higher number of nodules found on white clover in lucerne-conditioned soil suggests that root–rhizobia associations may have reduced foliar herbivore performance. Our study provides evidence that foliar herbivores are affected by plant–soil biotic interactions and that prolonged drought may influence aboveground–belowground linkages with potential broader ecosystem impacts.

Liriomyza trifolii (Burgess) (Diptera: Agromyzidae) is a polyphagous insect that is widely known for its invasiveness. Understanding the adaptation of L. trifolii to different host plants is critical in formulating effective approaches for integrated pest management (IPM). In this study, the effects of various host plants on L. trifolii were investigated by age-stage, two-sex life tables and transcriptome analysis. Our results show that the growth rate of immature L. trifolii on sponge gourd increased significantly relative to bean, but mortality was high. Mature L. trifolii adapted to sponge gourd had significantly increased longevity as compared to flies adapted to bean but exhibited reduced fecundity. The net reproductive rate, the intrinsic rate of increase, and the finite rate of increase of L. trifolii adapted to sponge gourd were significantly lower than those of flies adapted to bean. Transcriptome analysis showed the presence of 150 up- and 617 downregulated differentially expressed genes in L. trifolii adapted to sponge gourd as compared to flies adapted to bean. Genes encoding glutathione-S-transferase, cytochrome P450, and trypsin were significantly downregulated in L. trifolii adapted to sponge gourd as compared to bean. This study provides valuable insight into host plant effects on L. trifolii and provides a basis for the subsequent development of IPM measures such as push and pull, crop rotation, and biopesticide development.

The fall armyworm (FAW), Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae), is an important insect pest of maize (Zea mays L., Poaceae). The use of synthetic insecticides to control this pest remains the most popular option amongst growers. Natural insecticides offer a safer alternative to synthetic insecticides for controlling FAW. This study aimed to investigate the lethal and sublethal effects of a calcium carbonate formulation against this invasive insect pest. The tested formulation was a mixture of calcium carbonate (five concentrations), wetting agent and dispersant agent. Four experiments were conducted including a direct contact test, a no-choice feeding test, a choice feeding test and an oviposition test. The application of the calcium carbonate formulation on maize leaves had a strong anti-oviposition effect for adult female FAW, but a low-to-moderate antifeedant effect on FAW larvae. The growth and development of FAW larvae were only slightly affected by the calcium carbonate formulation in the feeding and the direct contact tests. The lethal effects of the calcium carbonate formulation against FAW larvae were low in direct contact and feeding tests. These results indicate that a calcium carbonate formulation has the potential to be used as the push component in a push–pull strategy for FAW control. Considering its low toxicity, both through direct contact and feeding, calcium carbonate can be an environmentally friendly alternative for the management of FAW.