Neotropical Entomology最新文献

This study investigates the comprehensive effects of the southern green stink bug, Nezara viridula L. feeding on canola seed germination and seed chemical quality (proteins, lipids, oligosaccharides, dry matter, and fatty acid profile). Damaged siliques originated significantly higher percentages of abnormal seedlings and dead seeds. Seed quality analyses demonstrated that damaged seeds showed lower levels of lipids and dry matter but higher levels of crude proteins. The fatty acid profile in seed oil was altered due to stink bug feeding, with increased levels of oleic, stearic, and linoleic acids and decreased levels of linolenic acid. Regarding oligosaccharides, the fructose and stachyose levels were notably lower in damaged seeds, whereas the sucrose level was higher. Multivariate analysis using principal components analysis provided a structured overview of their interrelationships. Therefore, these results clearly demonstrate that, although N. viridula is not considered a main pest of canola, its feeding activities on this plant results in substantial seed damage and detrimental alteration of seed chemical compounds.

This study addresses historical uncertainties regarding morphological variation in the paraprocts of Tupiperla illiesi, a stonefly with a complex taxonomic history. We tested whether these variations represent phenotypic plasticity or distinct species using integrative taxonomy. Adult gripopterygids were collected from Estação Biológica de Boracéia utilizing Malaise and light traps. The morphology of the specimens was analyzed in accordance with existing literature, and selected individuals underwent DNA extraction, amplification, and sequencing of the cytochrome c oxidase subunit I (COI) barcode region. Molecular distances were estimated using the Kimura 2-parameter model, and clustering was determined using Neighbor-Joining and Bayesian methods. Species delimitation was further refined using the SPdel pipeline. The combined analysis of COI sequence and morphological differences in the paraprocts led to the identification of distinct morphotypes within T. illiesi, resulting in the description of a new species, Tupiperla tucum sp. nov.

The fruit fly Anastrepha fraterculus (Wiedemann) (Diptera: Tephritidae) is one of the main pests in apple orchards. Artificial neural networks (ANNs) are tools with good ability to predict phenomena such as the seasonal dynamics of pest populations. Thus, the objective of this work was to determine a prediction model for the seasonal dynamics of A. fraterculus in apple orchards using ANNs. Insect densities and climatic elements were monitored for 8 years in two commercial apple orchards. Of the 1452 ANNs determined, the one with meteorological data with a 35-day lag was selected. This ANN presented the highest correlation (0.693) between predictions and pest densities, the lowest square root mean validation error (0.066), and five neurons in the hidden layer. Among the model's predictors, wind speed and relative humidity showed positive correlations with pest density, while precipitation was negatively correlated. The predicted population curves, based on the fruiting period and temperature, reached a peak in the number of A. fraterculus individuals per trap per day. ANN was able to adequately predict pest density in different orchards, plant fruiting stages, and years. Therefore, this ANN model is promising for predicting A. fraterculus densities in apple orchards.

Insect chemoreception is essential for locating food, selecting oviposition sites, and detecting infochemicals. In tephritid fruit flies, chemosensory perception occurs primarily through sensilla on the antennal flagella, maxillary palps, and ovipositor. Identifying these sensilla provides insights into olfaction, which may lead to improvements in insect control measures. This study describes the morphology of sensilla in Anastrepha obliqua (Macquart) using scanning electron microscopy, assesses their permeability to crystal violet and silver nitrate, and evaluates antennal electrophysiological responses (EAG) to host volatiles. Sensilla were classified into multiple types based on morphology and staining properties. The antennal flagella housed four types of sensilla (trichodea, basiconica, clavata, and coeloconica), whereas the sensory pit contained peg-like and coeloconica-like sensilla. Sensilla trichodea were silver nitrate-positive but refractory to crystal violet, whereas sensilla basiconica, clavata, and coeloconica were permeable to both stains, indicating olfactory function. Maxillary palps exhibited mechanosensory sensilla chaetica and olfactory sensilla basiconica; only sensilla basiconica were permeable to both stains. The aculeus contained bristle-like, peg-like, and campaniform sensilla, suggesting its role in mechanoreception and chemoreception. EAG recordings demonstrated that all tested volatiles elicited antennal responses, with no significant differences between sexes, except for propyl butyrate, which induced a stronger response in males. This is the first study to characterize the sensilla of the palps and ovipositor in Anastrepha species and provides a foundation for future olfactory and behavioural research.

Lucilia sericata (Meigen, 1826) maggot excretions/secretions (ES) have demonstrated anti-inflammatory and wound healing potential on corneal epithelial cells. This study aimed to evaluate the in vitro antibacterial potential of the ES against clinically relevant Gram-negative Pseudomonas aeruginosa and Gram-positive Staphylococcus epidermidis in the presence of human tear fluid. The ES was collected from sterile first- and second-instar L. sericata maggots. Antibacterial activity was assessed using colony-forming unit (CFU) and turbidimetric (TB) assays. In CFU assays, samples were incubated at 37 °C for 2 h, followed by serial dilutions and agar plate inoculation. For TB assays, samples were incubated for 16 h at 37 °C, with optical density measured at 550 nm. Against P. aeruginosa, maggot ES exhibited a paradoxical effect: growth inhibition was observed at lower concentrations (0.75 and 1.5 µg/mL), whereas higher concentrations (8-130 µg/mL) showed no antibacterial activity. Addition of human tear fluid led to an enhanced antibacterial activity at the lower concentrations, producing an effect stronger than either tears alone or ES alone. The antibacterial activity was consistent across three maggot batches and remained unaffected by reconstituting maggot ES in phosphate-buffered saline. Heat-inactivation of maggot ES resulted in a loss of its antibacterial activity. Against S. epidermidis, maggot ES showed no antibacterial activity at any of the tested concentrations (1.5-92 µg/mL). Lucilia sericata maggot ES exhibits differential antibacterial effects at lower concentrations, which are enhanced in presence of human tear fluid.

The argan tree (Argania spinosa L. Skeels), native to the sub-Saharan region of Morocco, is an endangered agroforestry species renowned for producing one of the world's most expensive and sought-after oils. However, this valuable resource is threatened by the Mediterranean fruit fly (Ceratitis capitata (Wied.)), an invasive pest worldwide. Like other dipteran insects, C. capitata has developed mutualistic interactions with prokaryotic endosymbionts, including Wolbachia, a facultative intracellular bacterium that could play a role in the biology of this pest. Between 2022 and 2024, a field survey was conducted in the argan forests of Agadir, southern Morocco, to detect Wolbachia in natural populations of C. capitata and investigate its potential impact on this pest. A total of eighteen wild type specimens were captured to investigate the endosymbionts of this insect pest. Detection of Wolbachia was carried out by PCR using a primer pair targeting a specific fragment within the cox gene. Amplicons of the expected size were sequenced in both directions, and one sequence was deposited in the GenBank under accession Number PQ285444. Phylogenetic analysis showed that the obtained sequence belongs to the monophyletic clade of the Wolbachia B supergroup, known to infect a variety of insect species. To the best of our knowledge, this is the first report of the bacterium being detected and characterized in natural populations of the Mediterranean fruit fly infesting argan fruits in the country. These findings open new perspectives for integrated biological control strategies, offering a sustainable alternative to chemical insecticides for managing this insect pest species in Morocco.

The control of dengue vector mosquitoes by utilizing plant-based eco-friendly larvicides is pivotal in suppressing the spread of dengue with minimum environmental toxicity. This study aimed to evaluate the larvicidal activity of nanoliposomes containing p-cresol and Myristica fragrans Houtt. essential oil (EO) against Aedes aegypti L. and Aedes albopictus (Skuse, 1894) larvae. The constituents of extracted EO were assessed by GC-MS analyses. The in vitro and in silico inhibitory activities of p-cresol and M. fragrans EO against acetylcholinesterase and α-amylase enzymes of Larvae were assessed. Nanoliposomes were prepared and characterized and their Larvicidal activities were analyzed against 4th instar Aedes larvae. Major constituents identified from EO were α-pinene, sabinene, β-pinene, β-phellandrene, γ-terpinene, isopulegol, and myristicin. The results showed that both p-cresol and M. fragrans EO possess significant inhibitory activity against α-amylase. Moreover, M. fragrans EO also inhibited the activity of acetylcholinesterase enzyme. The molecular docking results also confirmed these inhibitory activities. Myristica fragrans EO and p-cresol as well as their nanoliposomes showed significant larvicidal activities against Ae. aegypti and Ae. albopictus. The LC₅₀ values of p-cresol (13 and 16 mg/L) were lower than M. fragrans EO (33 and 39 mg/L) against both Ae. aegypti and Ae. albopictus larvae, respectively. The encapsulation efficacy of nanoliposomes for p-cresol and M. fragrans EO was 78 to 82%. The hydrodynamic diameter of nanoliposomes was below 155 nm. The PDI and zeta potential values were Less than 0.2 and - 28 mV respectively, confirming the homogenous distribution and stability. Here, it is concluded that both M. fragrans EO and p-cresol possess significant larvicidal activities against Aedes larvae. The nanoliposomes of M. fragrans EO and p-cresol were stable and homogenous, and these have further improved the efficacy of M. fragrans EO and p-cresol.

Successful biological control requires accurate knowledge of the host preference of the released parasitoid. Telenomus remus Nixon (1973) is an effective parasitoid of Spodoptera frugiperda (J.E. Smith) in many regions, but S. frugiperda is not ideal for mass rearing due to cannibalism and high feeding costs. This study evaluated the efficacy of T. remus by assessing parasitization and emergence rates on eggs of S. frugiperda and Spodoptera litura (Fabricius). Host preference was tested through choice and non-choice experiments using parasitoids reared on both hosts, and various host-parasitoid ratios were tested to assess density-dependent parasitism. Results showed that T. remus had higher parasitism and emergence rates on S. litura eggs, regardless of the rearing host. The highest parasitism was observed on S. litura (94.63%) from T. remus reared on S. litura eggs and the highest emergence rates was also on S. litura eggs from T. remus reared on S. frugiperda (88.03%). The lowest emergence rate (52.29%) was observed on S. frugiperda eggs under no-choice conditions. Parasitoids reared on S. frugiperda achieved the highest parasitism on S. litura eggs (98.11%) in host-parasitoid ratio tests, while the lowest emergence rate (55.02%) occurred when reared and tested on S. frugiperda. These results suggest that S. litura is a more suitable host for mass rearing T. remus, enhancing its potential as a biological control agent in the field.

This study evaluated the larvicidal efficacy of the methanol extract of Dactyloctenium aegyptium against Aedes aegypti (L, 1762) (Diptera: Culicidae), Anopheles stephensi Liston, 1901 (Diptera: Culicidae), and Culex quinquefasciatus Say, 1823 (Diptera: Culicidae). The methanol extract exhibited the highest mortality rates, achieving 100% mortality at 250 µg/mL for all species tested, and demonstrated the lowest LC₅₀ values of 94.28 µg/mL for Ae. aegypti, 119.07 µg/mL for An. stephensi, and 103.71 µg/mL for Cx. quinquefasciatus. In contrast, the n-hexane extract was the least effective against Ae. aegypti and Cx. quinquefasciatus, while the chloroform extract showed the least efficacy against An. stephensi. Statistical analysis confirmed the significant impact of extract concentration, type, and mosquito species on mortality rates, with the model explaining 98.4% of the variance. GC-MS analysis of the methanol extract identified several bioactive compounds, with stigmasterol being the most abundant (13.92%), followed by gamma-sitosterol (10.40%) and campesterol (5.31%). Molecular docking studies revealed that campesterol exhibited the highest binding affinity with docking scores of -9.6 kcal/mol for the sterol carrier protein from Ae. aegypti (PDB ID: 1PZ4) and -10.3 kcal/mol for acetylcholinesterase from Anopheles gambiae (PDB ID: 5X61). Additionally, stigmasterol and sitosterol showed significant binding affinities of -9.4 and -9.0 kcal/mol against 1PZ4, and -9.5 and -9.4 kcal/mol against 5X61, respectively. Citrost-7-en-3-ol demonstrated a promising affinity of -9.7 kcal/mol for acetylcholinesterase. Overall, the methanol extract of D. aegyptium shows promise for mosquito control, with specific compounds identified as potential inhibitors of key targets in vector control strategies.

The corn leafhopper, Dalbulus maidis (Hemiptera: Cicadellidae) and its associated corn diseases are considered the main production drawback currently faced by maize growers across South America, especially in Brazil. Native to Mexico and historically restricted to tropical America, the species has recently increased its occurrence in temperate areas of the continent, raising the need for a deeper understanding of the genetic basis driving its population dynamics. In this study, we used the partial mitochondrial DNA cytochrome c oxidase I (mtCOI) gene to characterize D. maidis collected in eight Brazilian sites and one Paraguayan site, as well as publicly available mtCOI data from Argentina and Mexico, to investigate genetic diversity and population structure of this important maize pest. Our results revealed low genetic diversity (π = 0.00162, Hd = 0.433) in the mtCOI partial gene region of the surveyed D. maidis populations. Six haplotypes were identified, with one potential ancestral (haplotype A) predominating in Mexico and tropical South America, and a second, possibly more recent one (haplotype B) standing out in temperate areas of the continent. The population structure detected indicates that outbreaks of D. maidis in different regions are associated primarily with local populations, with minor contribution from long-distance dispersal of insects, and limited gene flow across different countries and macro-regions. Based on these findings, pest management strategies should focus on suppressing winter survival and migration of D. maidis within a regional scale, thus reducing population pressure in maize crops.