AISLAMIENTO DE MICROORGANISMOS A PARTIR DEL FLUIDO DIGESTIVO DE LARVAS DE Rhynchophorus palmarum (COLEOPTERA: CURCULIONIDAE)

Se tuvo como objetivo aislar bacterias, levaduras y un hongo ascomiceto, a partir del fluido digestivo de larvas de Rhynchophorus palmarum. Las larvas fueron adquiridas en mercados de productos típicos de la Amazonia. Los ejemplares se seleccionaron de acuerdo a su peso y talla aproximados, para luego ser disecados en condiciones de esterilidad y obtener una suspensión de fluido intestinal, que fue diluida y sembrada en medio sólido y líquido. Para el aislamiento microbiano, se consideraron aproximaciones para el cultivo de bacterias y hongos o levaduras, tanto en condiciones aeróbicas como anaeróbicas y microaerófilas. Las colonias aisladas se llevaron hasta cultivos puros, obteniéndose un total de catorce aislados, representados en su mayoría por bacilos Gram negativos y, en menor proporción por hongos y levaduras. En cuanto a su requerimiento de oxígeno, la mayoría de los aislados corresponde a microorganismos aeróbicos, con una escasa presencia de aislados anaeróbicos y microaerófilos.

Aproximación al uso y aprovechamiento de insectos comestibles en las comunidades indígenas del oriente amazónico colombiano

En la Amazonía colombiana, los insectos constituyen un recurso natural abundante, el cual es aprovechado mediante el consumo de especies comestibles. Históricamente, los pueblos indígenas son entomofágicos y han incluido a insectos y otros artrópodos en sus dietas. En el presente estudio, se analiza el uso tradicional de insectos comestibles en las comunidades del oriente amazónico de Colombia. Durante el período de agosto 2020 a marzo 2021, se realizaron entrevistas abiertas y semi-estructuradas a habitantes del municipio de Mitú (Vaupés) y de 41 comunidades indígenas aledañas, las cuales indagaron sobre la percepción, aprovechamiento y comercialización de insectos comestibles. De acuerdo con su valor de uso, Rhynchophorus palmarum (Coleoptera: Curculionidae), Syntermes spinosus (Blattodea: Termitidae), Atta laevigata (Hymenoptera: Formicidae), Lusura chera (Lepidoptera: Notodontidae) y Polybia liliacea (Hymenoptera: Vespidae), constituyen las especies de insectos comestibles más representativas de la región. Para cada especie se estableció su calendario ecológico y se documentaron sus técnicas y métodos de recolecta, sus formas tradicionales de preparación y consumo, y sus actividades de comercialización. Se resalta el potencial de las especies de insectos comestibles analizadas para el fortalecimiento de estrategias de uso sostenible direccionadas a mejorar la seguridad alimentaria de la población y el mantenimiento de los conocimientos tradicionales de las comunidades.

Phoretic mite infestations associated with Rhynchophorus palmarum (Coleoptera: Curculionidae) in southern California

The South American palm weevil, Rhynchophorus palmarum (Coleoptera: Curculionidae), established in San Diego County, California, USA sometime around 2014. Attached to the motile adults of this destructive palm pest, we identified three species of uropodine mites (Parasitiformes: Uropodina), Centrouropoda n. sp., Dinychus n. sp. and Fuscuropoda marginata. Two of these species, Centrouropoda n. sp. and Dinychus n. sp. are recorded for the first time in the USA and were likely introduced by R. palmarum. Several species of mites, primarily of Uropodina, have previously been recorded as phoretic on Rhynchophorus spp. In this study, we examined 3,035 adult R. palmarum trapped over a 2.5-year period, July 2016 to December 2018, and documented the presence of and species composition of phoretic mites and their relationship with weevil morphometrics (i.e., pronotum length and width). The presence and species composition of mites on weevil body parts changed over the survey period. No mites were found under weevil elytra in 2016 and mite prevalence under elytra increased over 2017–2018 due to an increased abundance of Centrouropoda n. sp per individual beetle. Mite occurrence levels were significantly correlated with reduced pronotum widths of male weevils only. The significance of this finding on male weevil fitness is unknown. Potential implications of phoretic mites on aspects of the invasion biology of R. palmarum are discussed.

Behavioral and electrophysiological response of Rhynchophorus palmarum (L., 1764) (Coleoptera: Curculionidae) to volatile compounds of natives entomopatogenic fungi

Rhynchophorus palmarum es plaga relevante en palmeras (Arecaceae) en Brasil. Su respuesta comportamental (olfatometría) y electrofisiológica (electroantenografía, sola y acoplada a cromatografía) se estudió frente a compuestos orgánicos volátiles emitidos por hongos entomopatógenos nativos aislados en Coruripe (Alagoas, Brasil) mediante aireación durante 24 horas. El aislado CVAD01 no originó respuesta comportamental significativa, pero el CVAD02 originó atracción significativa en machos. Los bioensayos electrofisiológicos mostraron actividad antenal en los dos sexos de R. palmarum frente a los componentes volátiles de los extractos de los dos hongos identificados. Los análisis cromatográficos de los extractos indicaron perfiles de compuestos orgánicos volátiles con la presencia de dos alcoholes, tres hidrocarburos aromáticos, dos monoterpenos, tres cetonas y tres hidrocarburos lineales. Rhynchophorus palmarum is a major pest of palms (Arecaceae) in Brasil. Both the behavioral (olfactometry) and electrophysiological (electroantennography, both alone and coupled to chromatography) was studied against volatile organic compounds emitted by native entomopathogenic fungi isolated from Coruripe (Alagoas, Brazil). Fungal isolates were identified by aeration system for 24 hours. CVAD01 did not cause a significant behavioral response; however, males were significantly attracted to CVAD02 extracts. Electrophysiological bioassays showed antennal activity, in both sexes, to volatile components of the two identified native fungi. The chromatographic analysis of the extracts indicated profiles of volatile organic compounds with the presence of three alcohol, three aromatics, three ketones, and four hydrocarbons.

Rhynchophorus palmarum (Linnaeus, 1758) (Coleoptera: Curculionidae): Guarani-Kaiowá indigenous knowledge and pharmacological activities

Zootherapy is a traditional secular practice among the Guarani-Kaiowá indigenous ethnic group living in Mato Grosso do Sul, Brazil. My people use the oil extracted from larvae of the snout beetle Rhynchophorus palmarum (Linnaeus, 1758) to treat and heal skin wounds and respiratory diseases. Based on this ethnopharmacological knowledge, the chemical composition and antioxidant, antimicrobial, and healing properties of R. palmarum larvae oil (RPLO) were investigated, as well as possible toxic effects, through in vitro and in vivo assays. The chemical composition of the RPLO was determined using gas chromatography coupled with mass spectrometry. The antioxidant activity of RPLO was investigated through the direct 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay, and the antimicrobial activity was evaluated against Gram-positive and Gram-negative bacteria that are pathogenic to humans. The healing properties of RPLO were investigated by performing a cell migration assay using human lung fibroblasts (MRC-5), and the toxicity was analyzed, in vivo, using a Caenorhabditis elegans model and MRC-5 cells, in vitro. RPLO contains 52.2% saturated fatty acids and 47.4% unsaturated fatty acids, with palmitic acid (42.7%) and oleic acid (40%) representing its major components, respectively. RPLO possesses direct antioxidant activity, with a half-maximal inhibitory concentration (IC50) of 46.15 mg.ml-1. The antimicrobial activity of RPLO was not observed at a concentration of 1% (v/v). RPLO did not alter the viability of MRC-5 cells and did not exert toxic effects on C. elegans. Furthermore, MRC-5 cells incubated with 0.5% RPLO showed a higher rate of cell migration than that of the control group, supporting its healing properties. Taken together, RPLO possesses direct antioxidant activity and the potential to aid in the healing process and is not toxic toward in vitro and in vivo models, corroborating the safe use of the oil in traditional Guarani-Kaiowá medicine.

Antennal transcriptome sequencing and identification of candidate chemoreceptor proteins from an invasive pest, the American palm weevil, Rhynchophorus palmarum

For decades, the American palm weevil (APW), Rhynchophorus palmarum, has been a threat to coconut and oil palm production in the Americas. It has recently spread towards North America, endangering ornamental palms, and the expanding date palm production. Its behavior presents several parallelisms with a closely related species, R. ferrugineus, the red palm weevil (RPW), which is the biggest threat to palms in Asia and Europe. For both species, semiochemicals have been used for management. However, their control is far from complete. We generated an adult antennal transcriptome from APW and annotated chemosensory related gene families to obtain a better understanding of these species' olfaction mechanism. We identified unigenes encoding 37 odorant-binding proteins (OBPs), ten chemosensory proteins (CSPs), four sensory neuron membrane proteins (SNMPs), seven gustatory receptors (GRs), 63 odorant receptors (ORs), and 28 ionotropic receptors (IRs). Noticeably, we find out the R. ferrugineus pheromone-binding protein and pheromone receptor orthologs from R. palmarum. Candidate genes identified and annotated in this study allow us to compare these palm weevils' chemosensory gene sets. Most importantly, this study provides the foundation for functional studies that could materialize as novel pest management strategies.