Resumen En el presente trabajo se informan los números cromosómicos somáticos y/o gaméticos de 15 especies de insectos presentes en Argentina, que se caracterizan por su importancia económica como plagas de cultivos o controladores de plagas agrícolas, pertenecientes a los siguientes órdenes y familias: Neuroptera, Chrysopidae: Ceraeochrysa cincta (n = 5 + XY), Ceraeochrysa paraguaria (n = 5 + XY), Chrysoperla argentina (n = 5 + XY), Chrysoperla asoralis (n = 5 + XY) , Chrysoperla externa (n = 5 + XY), Leucochrysa cruentata (n = 7 + XY) y Plesiochrysa elongata (n = 5 + XY), Coleoptera, Coccinellidae: Cycloneda sanguinea (n = 9 + XYp), Eriopis connexa (n = 9 + XYp), Harmonia axyridis (n = 7 + XYp), Hippodamia convergens (n = 9 + XYp) y Melyridae: Astylus atromaculatus (n = 8 + XYp), Dermaptera, Forficulidae: Doru lineare (2n = 20), D. luteipes (2n = 20) y Diptera, Ulidiidae: Euxesta eluta (n = 5 + XY). Por primera vez, se cita información cromosómica para seis especies, incluyendo un número cromosómico gamético adicional para Euxesta eluta. Además, se da a conocer en Astylus atromaculatus un número cromosómico diferente a los recuentos previamente reportados.

Abstract In the present study, the somatic and gametic chromosome numbers in fifteen species of insects from Argentina are reported. Said species are characterized for their economic importance as pest of crops or as agricultural pest controllers. The species belonged to the following orders and families: Neuroptera, Chrysopidae: Ceraeochrysa cincta (n = 5 + XY), Ceraeochrysa paraguaria (n = 5 + XY), Chrysoperla argentina (n = 5 + XY), Chrysoperla asoralis (n = 5 + XY), Chrysoperla externa (n = 5 + XY), Leucochrysa cruentata (n = 7 + XY) y Plesiochrysa elongate (n = 5 + XY), Coleoptera, Coccinellidae: Cyclonela sanguinea (n = 9 + XYp), Eriopis connexa (n = 9 + XYp), Harmonia axyridis (n = 7 + XYp), Hippodamia convergens (n = 9 + XYp), y Melyridae: Astylus atromaculatus (n = 8 + XYp), Dermaptera, Forficulidae: Doru lineare (2n = 20) and D. luteipes (2n = 20), Diptera, Ulidiidae: Euxesta eluta (n = 5 + XY). Chromosomal information for six species and additional gametic chromosome number for Euxesta eluta are established for the first time. In addition, a new chromosome number is cited for Astylus atromaculatus that is different to the one previously reported.

ABSTRACT Euxesta sp. (corn-silk fly) is a highly polyphagous insect genus that affects horticultural crops, fruit trees, and industrial crops. It causes huge economic losses in sweet corn (maize). Damage is caused by larvae feeding on corn silk, kernels and the remainder of the cob. Chemical treatments applied to maize crops are often not effective; therefore, efforts to control the fly must focus on finding alternative methods, such as biological control. The aim of this work was to determine the effects of Euxestophaga argentinensis (Hymenoptera, Figitidae) parasitism on corn-silk fly larvae, in two different planting dates: late winter and late summer. Samples were taken during spring and autumn in a commercial Bt sweet corn for two consecutive years. A total of 20 ears of corn per sample were collected at random and were placed in plastic trays, stored at 22 ± 2°C and 70 ± 5% RH and exposed to a 14:10 h photoperiod. Euxesta eluta and Euxesta mazorca pupae were separated, placed in separate plastic vials and periodically checked for emergence of adult flies and parasitoids. E. eluta has greater potential to damage sweet corn crops than E. mazorca. Parasitism was higher in late winter than in late summer, while only E. eluta was parasitized.

RESUMEN Euxesta spp. (mosca de la mazorca) es un género de insectos altamente polífagos que afectan los cultivos hortícolas, árboles frutales y cultivos industriales. En el maíz dulce causa altas pérdidas económicas. El daño es causado por la alimentación de la larva sobre los estigmas, granos y restos de la mazorca. Los tratamientos químicos aplicados a los cultivos del maíz frecuentemente no son efectivos, por lo tanto los esfuerzos en el control deben focalizarse en métodos alternativos, como el control biológico. El objetivo de este estudio fue determinar el efecto del parasitoide Euxestophaga argentinensis (Hymenoptera, Figitidae) sobre las larvas de la mosca, en dos épocas de siembra: fin de invierno y fin de verano, en lotes comerciales de maíz dulce Bt, en dos años consecutivos. Un total de 20 mazorcas de maíz por muestreo fueron recolectados al azar y se colocaron en bolsas plásticas herméticas y fueron mantenidos en laboratorio a 22 ± 2°C, 70 ± 5% RH y a 14:10 h de luz:oscuridad. Las pupas de E. eluta y E. mazorca fueron colocadas individualmente en tubos plásticos y revisados periódicamente hasta la emergencia del adulto de la mosca o del parasitoide. E. eluta tiene mayor potencial de daño que E. mazorca en los cultivos de maíz dulce. El parasitismo fue mayor en los cultivos sembrados en verano que en los de invierno tardío y solo E. eluta fue parasitada.

The aim of this study was to comparatively characterize the monthly variation and the sex ratio of Euxesta stigmatias (Loew) and Euxesta sororcula (Wiedermann) populations from a natural reserve and from a guava orchard. It was also investigated whether density and the climate factors affected the individuals' size and fluctuating asymmetry (FA). In both environments, E. sororcula predominated over E. stigmatias. The number of individuals of E. sororcula collected in the ecological station was significantly lower than the number of individuals caught in the orchard. However, the number of captured individuals of E. stigmatias did not differ between environments. Significant sex ratio differences were detected between the collection sites. Female's frequency of E. stigmatias was significantly higher than male's frequency in the ecological station, but not in the orchard. An opposite pattern was encountered for E. sororcula population, showing a significant larger number of females only in the orchard. The species populations also differed in the degree of asymmetry presented. Euxesta stigmatias individuals showed no change on size or on FA along the captures and between environments. Moreover, E. sororcula tended to be more susceptible to climatic variations, considering the significant observed correlation between temperature and body size and the expressive body size and FA variations. This study illustrates the influence of the environment in some structural and dynamic parameters of the studied populations.

Levantamento de mosca-da-espiga (Diptera: Ulidiidae) em milho (Zea mays L.) e primeiro relato de ocorrência de Euxesta mazorca Steyskal no Brasil. Espécies de Euxesta (Diptera, Ulidiidae), conhecidas como moscas do cabelo ou moscas da espiga estão aumentando em importância nas culturas de milho em diferentes países, embora muito pouco se conheça sobre elas no Brasil. As larvas das espécies representativas de Ulidiidae inicialmente danificam a parte reprodutiva feminina da planta e depois os grãos em desenvolvimento. Como resultado da alimentação das larvas ocorre fermentação e odor forte tornando a espiga inapropriada para o consumo humano ou animal. O principal objetivo deste trabalho foi avaliar a incidência de espécies de Euxesta em áreas de produção de milho e identificar as espécies predominantes usando dois atraentes alimentares diferentes à base de proteínas hidrolisáveis, BioAnastrepha® (proteína hidrolisável de milho) e Torula, colocados no interior de armadilha McPhail. As duas espécies identificadas foram E. eluta Loew and E. mazorca Steyskal, registrada pela primeira vez no Brasil. Entre as espécies, E. eluta foi predominante no milho. Ambos os atraentes foram eficientes na captura das duas espécies. No entanto, as armadilhas com BioAnastrepha® capturaram significativamente mais insetos do que aquelas com Torula.

Survey of ear flies (Diptera, Ulidiidae) in maize (Zea mays L.) and a new record of Euxesta mazorca Steyskalin Brazil. Species of Euxesta (Diptera, Ulidiidae), known as silk flies or ear flies, are becoming increasingly important as maize insect pests in South America, although very little is known about them in Brazil. The larvae of some species of this genus initially damage female reproductive tissues, and then the developing kernels on the ear. As a result of feeding, fermentation and associated odors cause complete loss of the grain because it is no longer fit for human or livestock consumption. The main objective of this work was to evaluate the incidence of Euxesta spp. in Brazilian maize fields and to determine the most prevalent species using two different hydrolyzed protein foods attractants, BioAnastrepha® (hydrolyzed maize protein) and Torula, placed inside McPhail traps. The two species identified were E. eluta Loew and E. mazorca Steyskal, the latter being a new record from Brazil. Between the two species, E. eluta was the more abundant in maize fields. Both attractants were efficient in capturing the two species. However, BioAnastrepha® captured significantly more insects than Torula.

Bt sweet corn is attacked by species of the genus Euxesta Loew that were considered as secondary pests, causing severe damage to sweet corn in Santa Fe province (Argentina). Two species have been identified: E. mazorca Steycal and E. eluta Loew, both appearing simultaneously and producing serious losses. Larvae attack the silks and consume the kernel contents, especially in the tips, although they can extend to all the ear length. The activity of these larvae constitutes one way of entrance for saprophytic microorganisms, making the product unmarketable for direct consumption. Dettmeria Borgmeier (Hymenoptera: Figitidae) was identified parasitizing larvae of the genus Euxesta, but at a low level.

Los maíces dulces Bt son atacados por especies del género Euxesta Loew, antes consideradas como plagas secundarias, lo que provoca daños severos en los maíces dulces del cinturón hortícola santafesino. Se han identificado dos especies del género, E. mazorca Steykal y E. eluta Loew, que aparecen en forma simultánea y causan severas pérdidas. En los ataques, las larvas comienzan a dañar los estigmas, luego se produce el vaciado de los granos, especialmente los apicales, aunque el daño pueden extenderse a toda la espiga. La acción de estas larvas constituye además una vía de ingreso de microorganismos saprofíticos, lo que se traduce en la pérdida del producto e impide su comercialización para consumo directo. El género Dettmeria Borgmeier (Hymenoptera: Figitidae) fue identificado parasitando larvas del género Euxesta, aunque en bajo porcentaje.

Este trabalho avaliou a infestação de duas espécies de maracujá por tefritídeos e lonqueídeos em dois municípios produtores do Sudeste do Brasil. Botões florais de maracujá doce (Passiflora alata) e maracujá azedo (Passiflora edulis f. flavicarpa) foram coletados em Seropédica (RJ) e Vila Valério (ES), respectivamente. Frutos de P. alata foram também coletados em Seropédica. Três espécies de Lonchaeidae foram obtidas de botões florais de P. alata (Neosilba zadolicha McAlpine & Steyskal, Neosilba sp. e Dasiops longulus Norrbom & McAlpine), e espécies de quatro gêneros de Tephritoidea foram obtidas de frutos: Anastrepha pseudoparallela Loew (Tephritidae), Dasiops frieseni Norrbom & McAlpine (Lonchaeidae), Euxesta sp. e Notogramma cimiciforme Loew (Otitidae). Exemplares de Ganaspis sp. (Figitidae: Eucoilinae) foram obtidos de alguns frutos de maracujá doce infestados por tefritídeos ou lonqueídeos. Dos botões florais de maracujá azedo, foram obtidos apenas espécimes de Dasiops inedulis Steyskal (Lonchaeidae). Parasitóides do gênero Opius Wesmael (Braconidae: Opiinae) foram também coletados associados a essa espécie de mosca.

This paper evaluated the infestation of two passion fruit species by tephritids and lonchaeids in two municipalities of southeastern Brazil. Floral buds of sweet passion fruit (Passiflora alata) and yellow passion fruit (Passiflora edulis f. flavicarpa) were collected in Seropédica (RJ) and Vila Valério (ES), respectively. Fruits of P. alata were also collected in Seropédica. Three species of Lonchaeidae were obtained from floral buds of P. alata (Neosilba zadolicha McAlpine & Steyskal, Neosilba sp. and Dasiops longulus Norrbom & McAlpine), and species of four genera of Tephritoidea were obtained from fruits: Anastrepha pseudoparallela Loew (Tephritidae), Dasiops frieseni Norrbom & McAlpine (Lonchaeidae), Euxesta sp. and Notogramma cimiciforme Loew (Otitidae). Specimens of Ganaspis sp. (Figitidae: Eucoilinae) were recovered from some sweet passion fruits infested by tephritids or lonchaeids. Only specimens of Dasiops inedulis Steyskal (Lonchaeidae) were obtained from floral buds of yellow passion fruit. Parasitoids belonging to the genus Opius Wesmael (Braconidae: Opiinae) were also collected in association with this fly species.