Development of antennal sensilla of Tetragonisca angustula Latreille, 1811 (Hymenoptera: Meliponini) during pupation

The antennal sensilla are sensory organs formed by a group of neurons and accessory cells, which allow perception of environmental cues, which play a role as mechanoreceptors and chemoreceptors. This study describes the post-embryonic development of the antennal sensilla of the stingless Tetragonisca angustula (Hymenoptera: Meliponini) workers. The development of the antennal sensilla begins in the transition stage of the pre-pupae to white-eyed pupae. The sensilla are completely developed at the black-eyed pupae stage, but they are covered by the old cuticle. The sensilla are exposed to the environment only in newly emerged workers of T. angustula, but it is possible that environmental stimuli can be recognized due to the pores in the old cuticle.As sensilas antenais são órgãos sensoriais formados por um conjunto de neurônios que captam estímulos ambientais e células acessórias, desempenhando as funções de mecanorreceptores e quimiorrecepterores. Este trabalho descreve o desenvolvimento pós-embrionário das sensilas antenais de operárias das abelhas sem ferrão Tetragonisca angustula (Hymenoptera: Meliponini). O desenvolvimento das sensilas tem início na transição de pré-pupa para pupa de olho branco e estão completamente desenvolvidas no estágio de pupa de olho preto, mas ainda estão cobertas pela cutícula velha. As sensilas estão completamente expostas em operárias recém-emergidas de T. angustula, mas é possível que estímulos ambientais sejam percebidos em estágios anteriores devido aos poros presentes na cutícula velha

Can the understory affect the Hymenoptera parasitoids in a Eucalyptus plantation?

The understory in forest plantations can increase richness and diversity of natural enemies due to greater plant species richness. The objective of this study was to test the hypothesis that the presence of the understory and climatic season in the region (wet or dry) can increase the richness and abundance of Hymenoptera parasitoids in Eucalyptus plantations, in the municipality of Belo Oriente, Minas Gerais State, Brazil. In each eucalyptus cultivation (five areas of cultivation) ten Malaise traps were installed, five with the understory and five without it. A total of 9,639 individuals from 30 families of the Hymenoptera parasitoids were collected, with Mymaridae, Scelionidae, Encyrtidae and Braconidae being the most collected ones with 4,934, 1,212, 619 and 612 individuals, respectively. The eucalyptus stands with and without the understory showed percentage of individuals 45.65% and 54.35% collected, respectively. The understory did not represent a positive effect on the overall abundance of the individuals Hymenoptera in the E. grandis stands, but rather exerted a positive effect on the specific families of the parasitoids of this order

Combinations of Metarhizium anisopliae with chemical insecticides and their effectiveness in Mahanarva fimbriolata (Hemiptera: Cercopidae) control on sugarcane

Some insecticides can be used jointly with entomopathogenic fungi, and therefore the combi- nation of chemical and biological control measures can be a safe and effective method to con- trol insect pests. The aim of this study was to evaluate the costs and efficacy of combinations of Metarhizium anisopliae (Metschnikoff) Sorokin (Hypocreales: Clavicipitaceae) with thiameth- oxam and imidacloprid on spittlebug (Mahanarva fimbriolata (Stål); Hemiptera: Cercopidae) control on sugarcane. The experiment was conducted as a randomized block design (RBD) with 10 treatments and 4 replications. The treatments included a control (untreated), thia- −1 −1 12 −1 methoxam (250 g ha ), imidacloprid (700 g ha ), M. anisopliae (M. a.) (3 × 10 conidia ha ), A1 (3 × 10 12 M. a. conidia ha −1 + 65 g ha −1 of thiamethoxam), A2 (3 × 10 12 M. a. conidia ha −1 + 125 g ha −1 of thiamethoxam), A3 (3 × 10 12 M. a. conidia ha −1 + 187.5 g ha −1 of thiamethoxam), A4 (3 × 10 12 M. a. conidia ha −1 + 175 g ha −1 of imidacloprid), A5 (3 × 10 12 M. a. conidia ha −1 + 350 g ha −1 of imidacloprid), and A6 (3 × 10 12 M. a. conidia ha −1 + 525g ha −1 of imidacloprid). The reductions in the numbers of M. fimbriolata nymphs per treatment compared to the control were similar at 15 DAT (days after treatment) in all treatments except combination A5 (M. anisopliae and thiamethoxam). At 30 DAT, the numbers of nymphs were significantly reduced in all treatments except A3, and their effectiveness ranged from 14.28% to 92.85%. At 45 DAT the numbers of M. fimbriolata nymphs per treatment were significantly reduced in the following treatments: imidacloprid alone at 700g ha -1 , A1, A2, A3, A4 and A6; and the combinations A1 and A2 caused the lowest M. fimbriolata nymph infestations and effectiveness rates of 77.41 and 87.09 %, respectively. At 75 DAT the 2 best control efficacies occurred in treatments A1 (3 × 10 12 M. a. conidia ha -1 of + 65g ha -1 of thiamethoxam) (82.1%) and A5 (78.6%) (3 × 10 12 M. a. conidia ha −1 + 350 g ha −1 of imidacloprid). At 90 DAT the number of nymphs in the control had increased 2.8 fold over the number at 75 DAT. Very good control efficacies at 90 DAT occurred in all treatments with the combination of the fungus with an insecticide. At 105 DAT the numbers of nymphs had surged in all treatments, and no treatment provided effective control. The treatments with the highest earnings per hectare were A1 (3 × 10 12 M. a. conidia ha -1 + 65 g thiamethoxam) and M. anisopliae alone at the recommended dose of 3 × 10 12 M. a. conidia ha -1 . Our findings demonstrate the effectiveness of using either thiamethoxam or imidacloprid in combination with M. anisopliae to control M. fimbriolata nymphs on sugarcane, but greater net earnings per hectare occurred with the lowest rate of the thiamethoxam combination than with any of the imidacloprid combinations.Algunos insecticidas se puede utilizar con hongos entomopatógenos y por lo tanto, la aso- ciación de los controles químico y biológico puede ser una estrategia segura y eficaz para el control de insectos-plaga. El objetivo de este estudio fue evaluar los costos y eficacia de combinaciones de Metarhizium anisopliae (Metschnikoff) Sorokin (Hypocreales: Clavi- cipitaceae) con insecticidas thiamethoxam e imidacloprid para el control de la chicharrita (Mahanarva fimbriolata (Stål); Hemiptera: Cercopidae) en caña de azúcar . El experimento fue conducido en un delineamiento en bloques casualizados (DBC), con 10 tratamientos y 4 repeticiones. Los tratamientos que incluidos el control (sin tratamiento), thiamethoxam (250 g ha −1 ), imidacloprido (700 g ha −1 ), M. anisopliae (M.a.) (3×10 12 conidios ha −1 ), A1 (3×10 12 conidios ha −1 de M. a. + 65 g ha −1 de thiamethoxam), A2 (3×10 12 conidios ha −1 de M. a. + 125g ha −1 de thiamethoxam), A3 (3×10 12 conidios ha −1 de M. a. + 187.5 g ha −1 de thiamethoxam), A4 (3×10 12 conidios ha −1 de M.a + 175 g ha −1 de imidacloprido), A5 (3×10 12 conidios ha −1 de M. a. + 350 g ha −1 de imidacloprido) y A6 (3×10 12 conidios ha −1 de M. a. + 525g ha −1 de imidacloprido). Las reducciones en el número de ninfas M. fimbriolata por tratamiento en comparación con el control fueron similares a los 15 DAT (días pos tratamiento) en todos los tratamientos excepto A5 combinación (M. anisopliae y thiamethoxam). A los 30 DAT, el número de ninfas se redujeron significativamente en todos los tratamientos, excepto A3, y su eficacia varió de 14,28% para 92,85%. A los 45 DAT, los números de ninfas M. fimbriolata por tratamiento se redujeron significativamente en los siguientes tratamientos: imidacloprido solo en 700 g ha -1 , A1, A2, A3, A4 y A6; y las combinaciones de A1 y A2 causaron la más bajo infestaciones de ninfas M. fimbriolata y sus tasas de eficacia fueron de 77,41 y 87,09%, respectivamente. A los 75 DAT, los 2 mejores eficacias de control se produjeron en tratamientos A1 (3×10 12 conidios ha −1 de M. a. + 65 g ha −1 de thiamethoxam) y A5 (78.6%) (3×10 12 conidios ha −1 de M. a.+ 350 g ha −1 de imidacloprido). A los 90 DAT, el número de ninfas en el control había aumentado 2,8 veces más el número a 75 DAT. Muy buenas eficacias de control en 90 DAT, se produjo en todos los tratamientos con la combinación del hongo con un insecticida. A los 105 DAT, el número de ninfas habían aumentado en todos los tratamientos, y ningún tratamiento había proporcionado un control efectivo. Los tratamientos con los mayores rendimientos hectárea fueron A1 (3×10 12 conidios ha −1 de M. a.+ 65 g de thiamethoxam) y M. anisopliae solo a la dosis recomendada de 3×10 12 conidios ha −1 de M. a. Nuestros resultados demuestran la eficacia de thiamethoxam y imidacloprido en combinación con M. anisopliae para el control de ninfas M. fimbriolata en caña de azúcar, pero mayores beneficio neto por hectárea se produjeron con la tasa más baja de la combinación de thiamethoxam que con cualquiera de las combinaciones de imidacloprid

Ecological importance of lepidopteran defoliators on eucalyptus plantations based in faunistic and natural enemy analyses

Abstract Areas planted with Eucalyptus urophylla S.T. Blake variety platyphylla F. Muell. (Myrtaceae) expand annually in most regions of Brazil. Many lepidopteran species defoliate this plant, but with damage varying per species. The objective of this study was to identify the pest status of lepidopteran defoliators based in the faunistic analysis of these insects and of their natural enemies on E. urophylla variety platyphylla plantations in a representative producing region of Brazil. Adult moths of lepidopterans and of their natural enemies were captured using a light trap, installed every two weeks, from September 2016 to August 2018. A total of 183, 10, three and 139 lepidopteran species was captured and classified as primary, secondary, without defined importance to eucalypt plants and non-identified with 1,419, seven, 465 and 876 individuals, respectively. Two primary pest species were constants, two accessories and six accidentals and all secondary ones were accidentals. Six primary pest species were common and dominant and four non-dominants. Faunistic indices indicated the main lepidopteran species that should be monitored in pest management programs. Seven hymenopteran species (65 individuals), three dipterans (49 individuals) and two hemipterans (four individuals) were the natural enemies collected using light traps. The monitoring of lepidopteran pests with light traps can contribute to the management and to reduce damage and control costs for these species, besides identifying natural enemies for biological control programs in Eucalyptus plantations