Neotropical Entomology最新文献

Commercially available in Brazil since the 2013/2014 crop season, the adoption of Bt soybean rapidly increased to > 80% after only eight crop seasons (2020/2021). The widespread use of Bt soybean has achieved regional suppression of key lepidopteran pests and reduced insecticide use, providing economic and environmental benefits for all in Brazilian agriculture. Due to the high efficacy of Bt soybean in controlling key soybean lepidopteran pests and the simplicity of its use, most soybean farmers have adopted Bt soybean in extensive areas, reaching 94% adoption in the 2023/2024 crop season. However, the high adoption of Bt soybean associated with low refuge compliance has led to the first cases of pest resistance to Cry1Ac (Crocidosema sp. and Rachiplusia nu) in Brazil, representing major challenges to the future of this technology. Unfortunately, farmers wrongly believe that non-Bt soybean cultivars cannot be as profitable and productive as Bt soybean cultivars. Therefore, more than 10 years after Bt soybean adoption in Brazil, this review discusses the most important benefits and challenges of Bt soybean use and what can be expected for the next decade of this technology.

Feltia repleta (Walker, 1857), popularly known as "greater cutworm" in the USA and Canada and "cortador grande" in Latin America, is an important pest species occurring throughout the Americas. The popular name refers to its size and the habits of the larvae, which frequently cut shoots of seedlings, causing severe injuries or death of the host plant. Despite its importance to crops management, the immature stages of this species were never described in detail; moreover, they are frequently confused with many other agrotines, specially with species of Feltia Walker, 1856 and Agrotis Oschenheimer, 1816. Therefore, this study aims to describe the external morphology and the tegument ultra-structure of the immature stages of Feltia repleta based on exemplars obtained from a female collected in Planaltina, Brasília, Distrito Federal, Brazil, whose larvae were fed with artificial diet. Descriptions of the morphology with illustrations are presented, based upon observations through scanning electron microscopy and stereoscopic and optic microscopes attached to a camera lucida. Descriptions and illustrations of the eggs, first and last instars head capsule, chaetotaxy, tegument, and setae, and both sexes pupae are presented and the morphological characters are discussed and compared with immature stages of other species of agrotines. Additionally, a comprehensive list of host plants and a geographic distribution map based both on literature and new data based on studied specimens are provided.

The Neotropical region is a vast and heterogeneous ecozone harboring diverse Drosophilidae Fallén 1823 species. However, these species' distribution patterns and climatic requirements are poorly understood. In this study, we aimed to estimate differences in the climatic niche and distribution patterns among species to test the hypothesis that endemic and cosmopolitan species occurring in the Neotropics present different climatic niches, such that distribution range and niche breadth are highly correlated among species. For this task, we evaluated the geographic distributions and the climatic niches of 47 endemic and cosmopolitan drosophilids occurring in subtropical regions of the Neotropics using raw climatic data from collection records and environmental niche models (ENMs). We showed that the studied species varied in two highly correlated properties: the distribution ranges and the environmental niche breadth. Moreover, significant differences were observed between endemic and cosmopolitan drosophilids in terms of variable importance and climatic niches. Most of the studied species are distributed in regions under mild climatic conditions, but there are many species inhabiting harsher environments. Generally, the results suggest that several Neotropical drosophilid species may be highly vulnerable to global warming, potentially serving as bioindicator species for assessing the impact of climate change.

Tetranychus urticae Koch (Acari: Tetranychidae), commonly known as the two-spotted spider mite, is a major polyphagous pest that affects a wide range of vegetable crops. Infestation of T. urticae is more prominent on eggplant which causes 50-80% yield loss if no control measures initiated. The economic threat posed by T. urticae is constantly increasing because of the development of pesticide resistance and resurgence. One of best alternative management strategies is use of plant-based pesticides like secondary metabolites and essential oils (EOs) which provides sustainable and long-term protection. In the present study, EO extracted from a billygoat weed, Ageratum conyzoides L. (Asterales: Asteraceae), and its binary compounds were evaluated against T. urticae. The A. conyzoides EOs showed highest mortality (97.5% with the LC₅₀ 10.61 µL/mL), due to the presence of Precocene I (32.32%), Geraniol (1.23%), and Neral (0.55%). Among the binary compounds, Geraniol (95%) showed highest mortality having LC₅₀ (95%) of 9.59 µL/mL followed by Citronellol (77.5%) and Alpha-pipene (75%). Significant increase in the activity of esterases, glutathione S-transferase, and acetylcholine esterases contributed for the toxicity in T. urticae following exposure to essential oils (EO) and their binary compounds. SEM images revealed shrinking of the bodies of treated T. urticae along with reduced body measurements compared to the untreated individuals. The present study indicates that A. conyzoides EO could be used for development of new acaricides for sustainable management of T. urticae.

The alarming decline in bee populations throughout the world makes it imperative to understand the dynamics of its communities in undersampled tropical regions such as Colombian Choco and Amazon. Euglossine bees, also known as orchid bees, are the primary pollinators of orchids in the Neotropical region, and little is known about the resilience of these communities to geographical formations. Combining phylogenetics with the community ecology makes it possible to evaluate the evolutionary relationships among coexisting species, and to associate the phylogenetic structure of the community with the niche overlap and historical events. Here, we evaluated whether the orchid bee communities differ phylogenetically by altitudinal range on each side of the Andean mountains. We collected euglossine bees using chemical attractants at three different elevation levels in two sites (Putumayo and Nariño) separated by the Andean cordillera. We captured 1225 bees belonging to 64 species and four genera. We found phylogenetic clustering in Low and High Nariño, in contrast to Putumayo and Mid Nariño, which tended toward a random draw. However, overdispersion was not recorded; hence, the role of environmental filtering and competitive exclusion in community assembly along elevation gradients remains unclear. Consequently, we propose that the emergence of the Northern Andes generated changes in the composition of orchid bee communities distributed sympatrically. The niche conservatism observed in Nariño is explained by the narrow zone and climatic homogeneity and randomness in Putumayo, by the extension of the territory and other geological events such as Pleistocene refugees and Amazon River formation.

The blister beetle, Epicauta atomaria (Germar) (Coleoptera: Meloidae), is a Neotropical pest of various horticultural crops. This pest consume leaves causing significant reduction in the plant foliage. To develop sustainable tools for managing this insect species, we evaluated the repellent and insecticidal activity of ethanolic extracts from six plant species commonly found in Argentina: Artemisia annua (L.), Cantinoa mutabilis ((Rich.) Harley and J.F.B Pastore), Dysphania ambrosioides ((L.) Mosyakin and Clemants), Lantana camara (L.), Ricinus communis (L.), and Taraxacum officinale (F.H Wigg). The results showed that D. ambrosioides was the most active extract, with strong repellent activity at concentrations below 200 μg/μL (1.5 mg/cm²). Additionally, the extract caused a mortality rate of 78% at 10 μg/μL after 24 h, with an LC₅₀ of 7.9 μg/μL against E. atomaria. The enzymatic activity of E. atomaria acetylcholinesterase was evaluated in vitro to reveal the mode of action, resulting in a 58% inhibition at 5.0 μg/μL. The main bioactive compounds in fractionated D. ambrosioides ethanolic extracts were identified by GC-MS. The extract contained high concentrations of thymol and carvacrol in the less polar fractions, which were the most active. The bioactivity of both compounds against E. atomaria was also tested, showing strong insecticidal activity with an LC₅₀ of 1.6 and 1.4 μg/μL for thymol and carvacrol, respectively. Overall, our results highlight the potential of D. ambrosioides as a biopesticide for managing E. atomaria.

Microplastic contamination is no longer confined exclusively to aquatic environments and their organisms. Over the past 20 years, microplastics have increasingly been recognized as a source of contamination in terrestrial ecosystems and the organisms that inhabit them. Some studies have reported that these contaminants can alter the intestinal microbiota of bees, which may also harm their immune system and, consequently, directly impact the health of these animals. These consequences can impair bees' ability to effectively carry out their foraging activities, potentially leading to the decline of the hive and negatively impacting the ecosystem services they provide through pollination. However, research linking microplastics to bees is still in its early stages. Therefore, this work conducted a systematic review, applying selection and exclusion criteria to studies published between 2000 and 2024 that mentioned bees or bee products in relation to microplastics. These publications were extracted from electronic databases (Google Scholar, Scielo, Scopus, PubMed, and Web of Science). With the keywords used, 920 works were found, of which 33 met the pre-established review criteria, produced between 2013 and 2024, most of them from Italy (six studies) and China (five studies). Among the 33 studies selected, twelve are bibliographic reviews, indicating the need for further primary studies related to the subject, since bees provide vital ecosystem services through pollination.

The functional relationship between ecosystem biodiversity and its functioning enables the categorization of organisms into guilds based on resource utilization, allowing for the assessment of biological diversity in modified environments over temporal scales, such as forest plantations. The present study sought to compare the composition of ant trophic guilds associated with the understory of eucalyptus stands at various stages of succession, aiming to determine whether turnover in species composition occurs within these guilds. We employed the Winkler extractor to collect litter ants in fifteen eucalyptus stands, ranging in age from 1.5 to 10.3 years. Our findings revealed the presence of fifteen ant guilds. The guild of small arboreal ants with massive recruitment exhibited a decline in species richness as the understory matured, while the guild of specialized predatory cryptic myrmicines demonstrated an increase in species richness in older stands. Camponotus crassus Mayr and Wasmannia auropunctata Roger were more prevalent in younger understory stands, whereas Pheidole fallax Mayr was predominantly found in native vegetation. Ants can serve as indicators of environmental conditions in eucalyptus plantations and contribute to environmental certification efforts. Our results demonstrate that eucalyptus plantations with understory vegetation effectively support the conservation of ant species over time, providing habitat for diverse ant guilds that utilize the available resources in this environment and may act as a species source for the surrounding landscape.

Euglossini bees are important native pollinators that are highly sensitive to environmental changes. Given that urbanization is one of the most significant drivers of land-use change, this study aimed to analyze the responses of Euglossini bee assemblages to urbanization. For this, Euglossini males were sampled with bait traps along an urbanization gradient quantified using the UrbanizationScore software, between September 2022 and August 2023, in Bahia state, Brazil. Linear Models and non-metric multidimensional scaling (nMDS) ordination were used to analyze the bees' response to urbanization. A total of 836 individuals were identified, representing 13 species and three genera, with Euglossa cordata (Linnaeus, 1758) and Eulaema nigrita Lepeletier, 1841 being the only species present in urban areas. The kleptoparasitic species Exaerete frontalis (Guérin, 1844) and Exaerete smaragdina (Guérin, 1844) were found exclusively in areas with lower urbanization intensity. Linear Models revealed that more than 80% of the variation in species richness (R² = 0.82), abundance (R² = 0.81), diversity (R² = 0.83), and dominance (R² = 0.81) can be explained by variations in urbanization intensity (p < 0.005). nMDS indicated distinct bee assemblages between urban and semi-natural areas, while the presence of peri-urban points within both ellipses (urban and semi-natural) may reflect the heterogeneous characteristics of these transitional areas. Our findings suggest that urbanization acts as an environmental stressor, modifying the structure and composition of Euglossini bees, leading to a simplification of their assemblages due to the intensity of urbanization.

Current evidence suggests that fragmentation might profoundly affect biological communities, including assemblages of orchid bees. The effects of fragmentation at the individual level, including their morphology, are still poorly understood. Here we explore variation in size and shape of wings of males of the euglossine Eufriesea violacea (Blanchard, 1840) inhabiting a strongly fragmented landscape in western Paraná state, Brazil. Bees were collected both in the largest Brazilian preserve of Seasonal Semideciduous Forest, the Parque Nacional do Iguaçu, and in small fragments in the region. We considered traditional landmarks of wings to evaluate their size, shape, and circularity (as a specific shape variation), and studied the allometries between body size and wing traits. We found evidence that, while wing size and allometries did not vary, wing shape, on the other hand, varied significantly, including its circularity, as individuals possessing more circular wings were found at Parque Nacional do Iguaçu. Even if data did not support larger wings in individuals from small fragments, the more circular wings found in males from the Parque Nacional do Iguaçu could be related to the higher maneuverability required for flying in most structurally complex environments.