Neotropical Entomology最新文献

Tetragonisca angustula, a widely distributed Brazilian stingless bee, is commercially valuable for national meliponiculture. Despite their crucial role in bee health, honey quality, and nutrient metabolism, the gut microbiota of these bees remains poorly studied. This study aimed to isolate and identify gut bacteria from T. angustula workers and assess their enzymatic activities (amylase, cellulase, invertase, proteases). Bees were collected from nest entrances and interiors and dissected for microbial culture in appropriate media. In this study, we isolated and identified 21 bacterial strains from worker guts, belonging to Firmicutes, Actinobacteria, and Proteobacteria, including genera such as Paenibacillus, Bacillus, Pantoea, and Pseudomonas. Among them, only two isolates Alkalicoccobacillus sp. (TaP 03) and an unidentified strain (Tetra 2P) showed broad enzymatic activity, with Tetra 2P presenting the highest enzyme indexes for amylase (3.13), cellulase (2.56), and protease (2.56). Invertase activity was also widespread, detected in most isolates. Quantitatively, Tetra 2P showed higher amylase (125.1 ± 7.6 mgAR·min⁻¹·mL⁻¹) and invertase (135.7 ± 17.4 mgAR·min⁻¹·mL⁻¹) activity. From 16 isolates, 12 showed significant invertase activity. These results suggest that gut-associated bacteria of this stingless bee may contribute to nutrient metabolism and honey quality through sucrose fermentation and polysaccharide degradation. This is the first study to isolate and identify bacteria from the gut of T. angustula. These findings could provide insights and contribute to future research on microbial functions and their potential applications in meliponiculture.

Baculoviruses are important bioinsecticides in integrated pest management, with in vivo production systems still predominant due to cost-effectiveness and scalability. However, inconsistencies in quality, such as viral infectivity and contamination, and polyhedra yield restrict their wider adoption. This study evaluated the infection dynamics of Spodoptera frugiperda multiple nucleopolyhedrovirus - Alphabaculovirus spofrugiperdae isolate 6 (SfMNPV6) in Spodoptera frugiperda larvae to determine the optimal harvest time for maximizing occlusion body (OB) yield. Larvae were exposed to three inoculum concentrations (1 × 10⁵, 1 × 10⁶, and 1 × 10⁷ OB/mL) and monitored daily from the third to the tenth day post-infection. We assessed larval survival, tegument color as an indicator of infection symptoms, and polyhedra yield. Results indicated dose-dependent variations in disease progression, with the infection peak occurring on days seven, eight, and ten for the highest to lowest inoculum concentrations, respectively. Pinkish tegument symptom was strongly correlated with maximum OB yield, making it a reliable visual indicator for harvest timing. Statistical modeling confirmed the relationship between tegument color and OB concentration, with pinkish larvae (symptomatic) significantly outperforming green (early infection stage) and gray (post-mortem period) larvae in virus production. This symptom-based monitoring provides a low-cost, non-invasive alternative to enhance timing in baculovirus harvest protocols. These findings suggest that optimizing harvest based on larval symptoms and dose-dependent infection dynamics can improve virus yield and product quality. This approach enhances the reliability of baculovirus-based bioinsecticides, providing a more effective production strategy to meet the increasing demand for biological control agents in sustainable agriculture, particularly as global pest pressures are intensified by climate change.

Mocis latipes (Guenée, 1852) (Lepidoptera: Erebidae) is the main pest of graminaceous plants in the American Continent, especially in warm areas. Under normal conditions, M. latipes populations have their densities maintained at equilibrium by different natural enemies, including microorganisms (viruses, bacteria, and fungi), nematodes, insects, arachnids, birds, and mammals. In the megadiverse insect order Diptera, the families Tachinidae and Sarcophagidae are important natural enemies of various invertebrates, including pests, since several species parasitize insects and other arthropods. In the present work, we report the fly species Chetogena scutellaris (Wulp, 1890) (Tachinidae: Exoristinae: Exoristini); Atacta brasiliensis Schiner, 1868 (Tachinidae: Exoristinae: Goniini); and Peckia (Sarcodexia) lambens (Wiedemann, 1830) (Sarcophagidae: Sarcophaginae) parasitizing caterpillars of M. latipes collected on pasture, in Alagoas state, Northeast Brazil. This is the first record of C. scutellaris parasitizing M. latipes in Alagoas, the first report of the occurrence of P. (S.) lambens in Alagoas, and the first report of P. (S.) lambens parasitizing M. latipes in Brazil. Additionally, we reviewed the records of Tachinidae and Sarcophagidae parasitizing M. latipes, as well as all other hosts reported for them, and discussed the importance of parasitic flies for natural biological control of this and other lepidopteran pests in agrosystems, based on the distribution and host specificity of parasitic flies reported so far.

The fruit fly causes yield losses of 40 to 80% in various fruit crops, resulting in an approximate annual loss of USD 100 million in Colombia. Anastrepha obliqua is a significant pest for the mango production sector. Although biopesticides are promising alternatives for its control, there are currently no registered biopesticides derived from biomass or extracts of entomopathogenic fungi with the Colombian Agricultural Institute (ICA) for this purpose. This study demonstrates for the first time the potential of biomass and extracts from a native entomopathogenic fungus, Metarhizium robertsii MT008, cultivated through a liquid fermentation process, to effectively control both adult and preimaginal stages of A. obliqua. The optimal fermentation time was determined to be 5 days, producing the highest concentration of viable biomass (5.3 × 10⁵ CFU mL^-1), along with 75.89 ppm of destruxin A and 147.58 ppm of destruxin B. The fungal extract caused 100% mortality in A. obliqua adults within 48 h. While the biomass without formulation achieved 100% mortality, a biomass prototype achieved nearly 90% mortality at doses of 0.10 and 0.20 mg of dry biomass per gram of vermiculite against the preimaginal stages of the fruit fly by 24 days post-inoculation under laboratory conditions. The results demonstrate strong potential for advancing biopesticides, as combining these bioactive agents could allow more effective control of A. obliqua populations in field conditions by causing mortality at two different stages of its life cycle.

The sweetpotato weevil, Cylas formicarius (Fabricius, 1798) (Coleoptera: Brentidae), is a serious pest of sweet potatoes, damaging crops in the field and  during storage. Its cryptic nature limits chemical control. Entomopathogenic fungi (EPF) like Metarhizium anisopliae sensu lato (s.l.) (Metschnikoff) Sorokin, 1883 (Ascomycota: Hypocreales) offer eco-friendly alternatives. This study aimed to isolate and characterize a native M. anisopliae s.l. strain from infected C. formicarius using morphological and molecular methods and to evaluate its biocontrol potential against the weevil under in vitro conditions. Morphological characteristics and molecular analyses were used to confirm the identity of the isolate. Virulence was tested at three spore concentrations and compared with the commercial M. anisopliae s.l. strain ARSEF5369. Scanning electron microscopy (SEM) was employed to visualize the infection process. Enzyme activities (chitinase, protease) were quantified to compare virulence between strains. The effects of culture media and temperature on fungal growth and sporulation were investigated to optimize mass production conditions. The native isolate caused higher adult mortality (96.7, 93.3, and 50%) than the commercial strain at 1.2 × 10⁸, 5.5 × 10⁷, and 6.2 × 10⁶ conidia/mL after 7 days. The median lethal concentrations 30 (LC₃₀) and LC₅₀ of M. anisopliae s.l. strain Pm04 against C. formicarius were 2.15 × 10⁷ and 3.7 × 10⁷ conidia/mL, respectively, while at 1.2 × 10⁸ conidia/mL, the lethal times 30 (LT₃₀) and LT₅₀ were 2.33 and 2.4 days. Fungal infection stages were evident under SEM, and native strain exhibited elevated enzymatic activities relative to the commercial strain. Optimal growth and spore yield occurred at 25 ± 1°C on sabouraud dextrose agar (SDA) medium. These results highlight the potential of the native M. anisopliae s.l. strain as a promising biocontrol agent against C. formicarius, warranting further evaluation under field conditions.

Alphitobius diaperinus Panzer, 1797 (Coleoptera: Tenebrionidae), a common insect in poultry farms, poses a significant threat to poultry production. However, this insect also shows potential as a nutritional source due to its high protein and fat content. Studying its biological cycle and metabolic profile is essential for understanding its biology and biochemistry, enabling the development of more effective control strategies based on biochemical targets. This study aimed to investigate the biological and metabolic aspects of A. diaperinus at different developmental stages, providing relevant information for future research. Insect samples, maintained in colonies, were analyzed morphologically and metabolically. Morphological measurements were performed using digitized images, while metabolic profiles were obtained through gas chromatography coupled with mass spectrometry. The average biological cycle was 54 days, from egg to adult. Morphological parameters revealed distinct patterns of larval growth, with a positive correlation between length and age. Significant biochemical transformations were observed in the levels of amino acids, sugars, and organic acids throughout development, reflecting the specific metabolic needs of each stage. These findings expand the knowledge of the biological and biochemical aspects of A. diaperinus, providing a foundation for more effective and sustainable management strategies for controlling this pest.

Reproductive behavior and the use of stridulatory signals are well-documented in Curculionidae. Euscepes postfasciatus is an agricultural pest of sweet potato for which effective control strategies are still lacking. In this context, the objective of the present study was to investigate the reproductive behavior and the associated acoustic and vibrational signals of this species. To analyze reproductive behavior, 100 mating pairs were observed; data were compiled in an ethogram. To study the stridulatory signals emitted in stressful and reproductive contexts, 20 and 50 pairs, respectively, were recorded using systems equipped with microphones and piezoelectric accelerometers for capturing airborne and vibratory components of stridulatory signals. Morphological analysis of the stridulatory apparatus was conducted in 30 specimens dissected and examined using scanning electron microscopy. During mating, variation was observed in the male's mounting behavior and in the female's responses. Females were found to emit a specific rejection signal, while males produced a copulatory signal, potentially to enhance female receptivity, along with a distinct behavioral display. Stress-induced signals did not differ between sexes and showed clear temporal differences with female rejection and male courtship signals. The morphology of the stridulatory apparatus conformed to the pattern described for Curculionidae, with no observed sexual dimorphism.

Thrips (Thysanoptera: Thripidae) are sucking pests that damage a wide range of crops worldwide. Chemical insecticides are the main strategy for their control, but species can vary in susceptibility or develop resistance. Here, we developed and validated a bioassay method (dip test) using soybean (Glycine max [L.] Merr.) leaf discs to evaluate the susceptibility of thrips to insecticides. We compared the susceptibility of Caliothrips phaseoli (Hood, 1912) to acephate and spinetoram assessed using this method with results of the IRAC Susceptibility Test Method 010, in which bean pod sections are dipped into an insecticide solution. Concentration-mortality data from both methods fit the probit model, with mortality lines showing similar parameters (intercepts and slopes) and mortality increasing with the increase of insecticide concentrations. The lethal concentrations (LCs) of acephate were similar for both methods, whereas spinetoram showed higher LCs in the proposed method. Nonetheless, mortality at field label doses of both insecticides was consistently high (96.5-100%) in both methods. In conclusion, acephate and spinetoram exhibited high lethality against C. phaseoli, and the proposed bioassay method, due to its simplicity, reliability, and statistical robustness, represents a reliable alternative to the IRAC method for assessing susceptibility of thrips species to insecticides.

Entomopathogenic fungi (EPF) are promising eco-friendly alternatives to chemical insecticides against various insect pests. We assessed the efficacy of different Beauveria bassiana (Bals.-Criv.) Vuill. strains against Brevicoryne brassicae (L.), a major pest of Brassica crops under both laboratory and field conditions. The virulence and endophytic properties of three strains of B. bassiana, the commercial strain GHA, the endemic one KA14 from the Democratic Republic of Congo (DRC), and GxABT-1 from Belgium, were assessed under laboratory conditions. Under field conditions in eastern DRC, the efficacy of the B. bassiana GHA was evaluated compared to that of a conventional insecticide. In vitro, the lethal time 50 (LT₅₀) values ranged from 3 days for B. bassiana GxABT-1 to 4 days for both GHA and KA14 following direct application of fungi. Aphid exposure to fungus-treated leaves at 7 and 14 days after inoculation (DAI) resulted in LT₅₀ values of 4 to 5 days for GHA and KA14. Regarding the endophytic potential, B. bassiana KA14 showed higher performance in colonizing plant tissues and improving plant height growth. In the dual-choice tests, aphids were initially attracted to fungus-treated plants at 7 DAI but showed no preference between treated and control plants at 14 DAI. Field trials indicated no significant difference between fungal and chemical insecticide treatments, but both significantly reduced B. brassicae infestation compared to the Control. Our results support the interest of exploring the potential of the endemic B. bassiana KA14 strain against various insect pests and applying different methods.

Aedes (Fredwardsius) vittatus (Bigot) has a native geographical distribution that encompasses tropical areas of Asia, Africa, and the Mediterranean region of Europe. In its native range, this mosquito species is a potential vector of the dengue, chikungunya, Zika, and yellow fever viruses. Currently, Ae. vittatus is reported in the Caribbean countries of Cuba, Jamaica, and the Dominican Republic. We report the discovery of one female Ae. vittatus captured on September 11, 2024, in X-Calakoop, located near a major tourist site in Yucatán. Additionally, 11 mosquito species were found: Aedes aegypti (Linnaeus), Aedes albopictus (Skuse), Aedes bimaculatus Coquillett, Aedes cozumelensis Díaz Nájera, Aedes podographicus Dyar & Knab, Aedes taeniorhynchus (Wiedemann), Culex coronator Dyar & Knab, Culex nigripalpus Theobald, Haemagogus mesodentatus Komp & Kumm, Limatus durhamii Theobald, and Toxorhynchites moctezuma (Dyar & Knab). Notably, Ae. albopictus was the most abundant mosquito in the collection, accounting for 77.5% of the adults and 78.66% of the immature stages. The identification of Ae. vittatus in Mexico represents the first record of this species for continental America. The discovery represents the 252nd species in the country and 49th in Yucatán. The increase in the distribution pattern may have implications for public health in tropical America.