Excito-repellent and Pesticide-Likeness Properties of Essential Oils on Carpophilus dimidiatus (Fabricius) (Nitidulidae) and Oryzaephilus mercator (L.) (Silvanidae).

Carpophilus dimidiatus (Fabricius) (Nitidulidae) and Oryzaephilus mercator (L.) (Silvanidae) are insect pests that cause severe damage in important walnut growing regions in the northwest of Argentina. The current management approaches for these pests involve the use of unsafe phosphorus pesticides whose overuse have led to farmworker poisoning, pest resistance issues, and environmental contamination. Plant extracts, particularly essential oils, are an alternative source of insect control agents. Excito-repellent essential oils can be used to develop ecofriendly tools for managing the pest population without affecting quality and visual appearance of the stored walnuts. Laboratory studies were conducted to assess the excito-repellent effects of C. dimidiatus and O. mercator of 12 essential oils derived from aromatic plants used as food additives and traditional medicine in Argentina: Aloysia citrodora (AC), Aloysia gratissima (AG), Aloysia gratissima var. Gratissima (AGG), Blepharocalyx salicipholius (BS), Hyptis mutabilis (HM), Lippia junelliana (LJ), Lippia turbinata (LT), Mentha x piperita (MP), Minthostachys mollis (MM), Minthostachys verticillata (MV), Origanum vulgare(OV), and Rosmarinus officinalis (RO). The most bioactive EOs (ERijk ≥ 70%) were Aloysia gratissima var. Gratissima (AGG), Minthostachys verticillata, and Lippia junelliana. Their bioactivity profile and chemical space, characterized from GC-MS measures, Generalized Estimating Equations, and Hierarchical Cluster Analysis, revealed that they are mixtures of very functionalized molecules with physicochemical properties similar to those of insecticides with low residual property that enter the insect body through the respiratory system by inhalation. The AGG, MV, and LJ oils are promising as protective agents of walnut products. In our laboratory, studies of their formulations for use in integrated pest management programs are still ongoing.

Revision of the ocellatus species-group of the genus Plumarius Philippi 1873 (Hymenoptera, Chrysidoidea, Plumariidae), with description of three new species from Argentina.

This contribution presents the study of species-group of Plumarius Philippi 1873, as the result of a survey of the morphological variation in males. The group is characterized by the large ocelli and transverse head. It consists of the following three new species: P. culminatus Diez, Fidalgo & Roig-Alsina, sp. nov., P. ocellatus Diez, Fidalgo & Roig-Alsina, sp. nov., and P. stangei Diez, Fidalgo & Roig-Alsina, sp. nov. A characterization of the group, descriptions, and illustrations are provided.

QSAR Study of Biologically Active Essential Oils against Beetles Infesting the Walnut in Catamarca, Argentina.

Essential oils from six species of aromatic plants collected in the Catamarca Province of Argentina were evaluated for their chemical composition and repellent and insecticidal activities against beetles of the genus Carpophilus (Coleoptera: Nitidulidae) and Oryzaephilus (Coleoptera: Silvanidae) that infest the local walnut production. Experimental data were analyzed using generalized estimating equations, with normal distribution and the identity link function. From the spectral information from the tested essential oils, we worked their molecular modeling as mixtures by developing mixture descriptors ( Dmix) that combined the molecular descriptor of each component in the mixture ( d i) and its relative concentration ( x i), i.e., Dmix = f( d i, x i). The application of chemoinformatic approaches determined that a combination of mixture descriptors related to molecular size, branchedness, charge distribution, and electronegativity were useful to explain the bioactivity profile against Carpophilus spp. and Oryzaephilus spp. The reported models were rigorously validated using stringent statistical parameters and essential oils reported with repellent activity against other beetle species from the Nitidulidae and Silvanidae families. This model confirmed each essential oil as a repellent with a comparable performance to the experimental reports.

Evolutionary History of the Hymenoptera.

Hymenoptera (sawflies, wasps, ants, and bees) are one of four mega-diverse insect orders, comprising more than 153,000 described and possibly up to one million undescribed extant species [1, 2]. As parasitoids, predators, and pollinators, Hymenoptera play a fundamental role in virtually all terrestrial ecosystems and are of substantial economic importance [1, 3]. To understand the diversification and key evolutionary transitions of Hymenoptera, most notably from phytophagy to parasitoidism and predation (and vice versa) and from solitary to eusocial life, we inferred the phylogeny and divergence times of all major lineages of Hymenoptera by analyzing 3,256 protein-coding genes in 173 insect species. Our analyses suggest that extant Hymenoptera started to diversify around 281 million years ago (mya). The primarily ectophytophagous sawflies are found to be monophyletic. The species-rich lineages of parasitoid wasps constitute a monophyletic group as well. The little-known, species-poor Trigonaloidea are identified as the sister group of the stinging wasps (Aculeata). Finally, we located the evolutionary root of bees within the apoid wasp family "Crabronidae." Our results reveal that the extant sawfly diversity is largely the result of a previously unrecognized major radiation of phytophagous Hymenoptera that did not lead to wood-dwelling and parasitoidism. They also confirm that all primarily parasitoid wasps are descendants of a single endophytic parasitoid ancestor that lived around 247 mya. Our findings provide the basis for a natural classification of Hymenoptera and allow for future comparative analyses of Hymenoptera, including their genomes, morphology, venoms, and parasitoid and eusocial life styles.

Revision of Plumarius Philippi 1873 (Hymenoptera: Chrysidoidea, Plumariidae) from Argentina north of Patagonia, with description of eighteen new species.

Twenty six species of Plumarius from Argentina north of Patagonia are revised. Eighteen new species: Plumarius politus sp. nov., P. sarophorus sp. nov., P. globulosus sp. nov., P. angulatus sp. nov., P. noa sp. nov., P. divergens sp. nov., P. malaris sp. nov., P. gracilior sp. nov., P. riojanus sp. nov., P. exophthalmus sp. nov., P. planatus sp. nov., P. albinervis sp. nov., P. truncatus sp. nov., P. mikrommatus sp. nov., P. obscurus sp. nov., P. gracilis sp. nov., P. fidalgoi sp. nov., and P. ocellulatus sp. nov. are described and illustrated. A new record for known species as well as a key to 26 known species in the region is given. A redescription of P. tumidulus Papp, 2000, which is the first record of the family Plumariidae from Uruguay, is done.