Neotropical Entomology最新文献

Several methods are available for identifying insect species, primarily based on morphological characteristics, molecular taxonomy, and geometric morphometry. However, integrative taxonomy is emerging as a robust approach, especially for closely related or taxonomically challenging species. In this study, reflectance spectroscopy in the visible and near-infrared ranges was employed to identify three beetle species within the Cyclocephala complex. A multivariate analysis of the spectral data enabled the development of a standardized methodology for identifying species with complex taxonomy by using spectral measurements from the beetles' elytra. Eight specific wavelengths-400 nm, 430, 440, 480 nm, 640 nm, 680 nm, 710 nm, and 1000 nm-were identified as promising for use in indices and models applicable to Cyclocephala taxonomy. Linear discriminant models applied to the spectral reflectance data successfully separated species with classification accuracy up to 84%. These findings highlight the potential of reflectance spectroscopy within the 400-1000 nm range as part of a comprehensive methodology for discriminating insect species complexes.

Riparian zones of the Atacama Desert and slopes of the Andes mountain range host a diversity of insect species still unknown, and some lineages of different species of Geometridae have been discovered in recent years in such areas. Here, we describe Physocleora polyphaga Vargas-Ortiz & Parra sp.nov., a polyphagous species closely related to several native plants, distributed in coastal valleys and slopes of the Andes mountain range in the northernmost Chile. We present their diagnostic morphological characteristics, some ecological traits, and a representation of its evolutionary history within Physocleora Warren 1897 from DNA barcode sequence data. To validate the hypothesis of conspecificity of the specimens found, we use species delimitation methods based on genetic distances and phylogenetics.

Atlantochodaeus, a new genus of Ochodaeidae from the Brazilian Atlantic Forest is described, discussed, and illustrated. Additionally, four new species belonging to Atlantochodaeus are described: Atlantochodaeus everardoi n. sp. and Atlantochodaeus paulseni n. sp., both recorded from Rio de Janeiro State; Atlantochodaeus hucheti n. sp. from Espírito Santo, Minas Gerais, Rio de Janeiro, and São Paulo States, and Atlantochodaeus oliviae n. sp. from Minas Gerais State. Detailed descriptions of these species are accompanied by a differential diagnosis and a distribution map. A dichotomous key for all South American genera of Ochodaeidae and the species of Atlantochodaeus is provided to aid in identification. A comprehensive comparative morphology study regarding Parochodaeus pectoralis (LeConte, 1868) (type species of Parochodaeus) and the Atlantochodaeus species are discussed and illustrated. A discussion about gland, mycangium and stridulatory apparatus of Ochodaeinae are also provided. These findings emphasize the richness of the Atlantic Forest and underscore the importance of detailed taxonomic studies in revealing its biodiversity.

Euschistus heros (Fabricius) (Hemiptera: Pentatomidae) is Brazil's most significant soybean stink bug pest, with outbreaks well-documented across various regions. However, during a collection expedition in soybean crops in Amapá State, Euschistus atrox (Westwood) was identified as the predominant Euschistus species in these areas. In this study, we characterized E. atrox both morphologically and molecularly, comparing it with E. heros. A laboratory experiment was designed to compare reproductive traits between the two species, and test for interspecific crosses. Female E. atrox exhibited lower fecundity compared to E. heros. The most surprising finding was that intercrosses between E. heros and E. atrox resulted in fertile offspring. We highlight the implications of these findings for species evolution and pest management in this critical group of insect pests.

To achieve sustainability in agricultural pest management, it is essential to integrate chemical and biological control by using selective insecticides. In this study, we evaluated the lethal and sublethal effects of both botanical and synthetic insecticides used for controlling the fall armyworm, Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae), on its natural enemy Doru luteipes (Scudder) (Dermaptera: Forficulidae). For this purpose, bioassays of mortality, behavior, and transgenerational effects were conducted. Botanical insecticides rich in acetogenins and limonoids caused less than 30% mortality in D. luteipes nymphs (2nd, 3rd, and 4th instars). In contrast, chlorantraniliprole-based insecticide (Premio®) was highly toxic, presenting mortality above 80% at all nymphal stages and reducing predation capacity by 55.9% and walking velocity by 28.4% compared to the control. Aqueous emulsion of the ethanolic extract from Annona mucosa seeds (ESAM) reduced the longevity of the adults by 32.72 days compared to the control. Chlorantraniliprole resulted in the shortest pre-oviposition period (9.4 days), followed by a limonoids-based botanical insecticide (Azamax®) (11.0 days). Fourth-instar nymphs of the F₁ generation showed lower viability (54.5%) in the treatment with aqueous emulsion of the methanolic fraction from Annona montana leaves (EFAMON). The annonin-based commercial botanical insecticide (Anosom®) affected life table parameters, reducing the intrinsic growth rate (r_m = 0.039) and finite rate of increase (λ = 1.04). These findings indicate that, under the specific exposure conditions used in this study, botanical insecticides are less hazardous to the natural enemy D. luteipes than synthetic insecticide. The data obtained highlight the selectivity of botanical insecticides and one synthetic insecticide for improving pest control while preserving natural enemies.

Understanding the complex interplay between environmental factors and mosquito populations is crucial for effective vector-borne disease control. In this study, we investigated the combined effects of temperature and Ateleia glazioviana toxicity on the development and survival of Aedes aegypti, utilizing artificial microcosms. The first experiment used A. aegypti eggs, with microcosms varying by room temperature (18 °C and 25 °C) and exposure to A. glazioviana leaves, either without prior incubation or with a 14-day pre-incubation period. The second experimental design involved introducing larvae, with microcosms varying by room temperature (18 °C and 25 °C) and exposure to A. glazioviana leaves after a 14-day incubation period. For both experiments, we used only ultra-pure water and food for the control. Our results demonstrate that plant leachate toxicity had a more pronounced effect than temperature, with increased toxicity levels driving higher larval mortality rates. This reduction in competition among surviving larvae led to the development of larger individuals, consistent with the temperature-size rule. Notably, the impact of leachate toxicity was most significant when A. aegypti was exposed during the egg stage. Additionally, we observed that elevated temperatures were linked to increased wing asymmetry and reduced body size, suggesting heightened developmental instability under environmental stress. These findings have important implications for biological control strategies, emphasizing the need for pre-emptive measures before oviposition. Moreover, they challenge the commonly held assumption that temperature alone is the dominant factor shaping A. aegypti populations in Neotropical regions, highlighting the complex role of other ecological stressors.

This research aimed to study the feeding behavior of Nezara viridula (L.) adults on canola stems and siliques using the electropenetrography (EPG) technique. Three distinct phases were identified: non-feeding (waveform Np), pathway (waveform Nv1-which was divided into three subtypes Nv1a, Nv1b and Nv1w), and feeding (waveforms Nv2 and Nv3), which follow previously identified waveforms for this species on soybean. The Nv3 waveform was divided into two subtypes (Nv3a and Nv3b). Biological meanings of the waveforms were proposed by correlating them with visual observations and histological studies. The waveform Np was correlated with insect resting/walking on plant surface; Nv1a with initial stylet insertion and secretion of gelling saliva to create a salivary sheath; Nv1b with deep stylet penetration plus secretion of more gelling saliva; Nv1w with stylet withdrawal, and Nv2 with xylem ingestion, as previously observed for N. viridula nymphs on soybean. Nv3a was correlated with laceration/maceration activities; and Nv3b with ingestion of the lacerated/macerated tissue. Regarding comparative analysis, the initial penetration and stylet withdrawal were both significantly longer on stems. Xylem ingestion did not differ significantly between substrates. Feeding events were more common on siliques, and overall duration of ingestion was greater on this substrate. Although no difference in overall duration of laceration/maceration (cell-rupture feeding strategy) was observed between stems and siliques, the average duration of each laceration/maceration event was greater on stems. Significantly more time was spent on non-feeding activities on siliques compared with stems.

Insects and mammals share a similar innate immune system. Galleria mellonella (L.), a beekeeping pest, is an alternative model organism for human health studies due to its immune response similarity and ability to be maintained at 37 °C. While oxidative stress and genotoxicity cause diseases, antioxidant enzymes and epigenetic mechanisms are effective in immunological response processes. Although parasitoid venoms are potential candidates for pharmacological applications such as anticoagulant, antibiotic, painkiller, antiviral and anticancer agents, the information pool is scarce to reflect their effects in humans. In an attempt to reveal the pharmaceutical significance of parasitoid venoms and their potential effects on human health, different venom doses of Pimpla turionellae (L.), the solitary endoparasitoid of G. mellonella, were injected into the host. Then, the levels of protein content, advanced oxidised protein products, lipid peroxidation, antioxidant power and glutathione in host haemolymph, and the amounts of methylation marker 5-methyldeoxycytidine monophosphate and strand breakage rates under neutral and alkaline conditions in host DNA were analysed. Principal component analysis was performed to determine the number of components that oxidative parameters depend on, and multivariate correlation analysis was applied to evaluate the effects of the parameters on each other. It was concluded that P. turionellae venom appeared to be one of the most effective pharmaceutical agents among parasitoid venoms. Also, the 0.01 venom reservoir equivalent dose qualified as immunotherapeutic dose.

Insects, due to their unrestricted reproduction, have been a long-known nuisance causing significant damage to various crops. Besides the synthetic chemical pesticides, the bioactive compounds derived from medicinal plants also make a positive contribution against the control of pests. In this concern, the present study investigated the biological activity of essential oil and isolated sesquiterpene alcohols, τ-cadinol and β-bisabolol, from Clausena indica leaves against three insect pests, Spodoptera litura, Helicoverpa armigera, and Tribolium castaneum. Four different concentrations (25, 50, 75, and 100 g L^-1) of oil, τ-cadinol, and β-bisabolol in both normal and microencapsulated forms were tested for their efficacy in the field trial. Among all the compounds, τ-cadinol exhibited strong toxicity (LD₅₀ = 35.93-52.94 µg larva^-1), antifeedant activity (DC₅₀ = 52.51-75.93 µg cm^-2), and oviposition deterrent activity (OD₅₀ = 56.73-67.18 µg cm^-2) against all the tested pests followed by β-bisabolol and leaf essential oil. Additionally, both the compounds demonstrated noteworthy acetylcholinesterase inhibitory activity with IC₅₀ values of 24.53-30.98 μg mL^-1 and 32.15-40.41 μg mL^-1 respectively comparable to the positive control, galantamine. Moreover, both τ-cadinol and β-bisabolol exhibited the strongest cytotoxicity against Sf9 cells lines with IC₅₀ of 15.27 and 17.82 µg mL^-1 respectively while IC₅₀ of 5.02 µg mL^-1 was shown by azadirachtin on the same cell line. Results of the field trial reveal that all tested compounds showed considerable mortality of S. litura and H. armigera. Although the treatments showed good insecticidal activity in the field trial, but modifications are required for the concentration of active ingredients in the formulation or even in the formulation to enhance the effect. The results obtained lay a foundation for future field applications of oil and isolated compounds as crop protectants.

Diamondback moth, Plutella xylostella (L.), is a major pest of cruciferous crops, whereas Aphis craccivora is a major sucking pest of leguminous crops. Indiscriminate use of synthetic insecticides for the control of insect pests leads to insecticide resistance, harmful to natural enemies of pests, pollinators, the environment, and consumers' health. Therefore, it is necessary to screen/identify alternate strategies to control the target pests. Steroidal saponins, a group of specialized amphiphilic metabolites, are known for their various biological properties. There are a few reports on insecticidal activities of steroidal saponins. In the present study, insecticidal activities of nine diverse steroidal saponins isolated from Trillium govanianum were evaluated against Plutella xylostella and Aphis craccivora. Among the molecules, govanoside E (3) was found more effective against Plutella xylostella (LD₅₀ = 0.91 µL/insect) after 96 h of treatment followed by govanosides D and F (1.44 and 1.56 µL/insect, respectively). Similarly, govanoside E was also found effective against Aphis craccivora (LD₅₀ = 1.04 µL/insect) followed by dehydroxy-diosgenin and pennogenin-triglycoside (1.19 and 1.36 µL/insect, respectively). Furthermore, govanoside E (3) showed promising repellency (RC₅₀ = 1043.20 µL/L) against Plutella xylostella. The molecules also showed a dose-dependent relationship with inhibitory effects on the reproduction of Aphis craccivora. In vitro enzyme inhibition/mechanism study confirmed that govanoside E (3) inhibited glutathione-S-transferase (GST) and carboxylesterase (CES1) in test insects. The present study suggested the potential utilization of steroidal saponins for the control of target pests based on field bio-efficacy results.