ABSTRACT Prosopis juliflora is a shrub that has been used to feed animals and humans. However, a synergistic action of piperidine alkaloids has been suggested to be responsible for neurotoxic damage observed in animals. We investigated the involvement of programmed cell death (PCD) and autophagy on the mechanism of cell death induced by a total extract (TAE) of alkaloids and fraction (F32) from P. juliflora leaves composed majoritary of juliprosopine in a model of neuron/glial cell co-culture. We saw that TAE (30 µg/mL) and F32 (7.5 µg/mL) induced reduction in ATP levels and changes in mitochondrial membrane potential at 12 h exposure. Moreover, TAE and F32 induced caspase-9 activation, nuclear condensation and neuronal death at 16 h exposure. After 4 h, they induced autophagy characterized by decreases of P62 protein level, increase of LC3II expression and increase in number of GFP-LC3 cells. Interestingly, we demonstrated that inhibition of autophagy by bafilomycin and vinblastine increased the cell death induced by TAE and autophagy induced by serum deprivation and rapamycin reduced cell death induced by F32 at 24 h. These results indicate that the mechanism neural cell death induced by these alkaloids involves PCD via caspase-9 activation and autophagy, which seems to be an important protective mechanism.

Prosapia simulans (Walker) is an important spittlebug species that attacks forage grasses of the genus Brachiaria (Trin.) Griseb. from Mexico to Colombia. This, and several other species of spittlebugs, cause important economic losses to the livestock production industry. Development of resistant cultivars is regarded as the best method of control. In the present study we used taxonomic keys, dissection of male genitalia and RAPD-PCR patterns to reconfirm the identity of P. simulans specimens collected in Colombia and Mexico. We were able to reconfirm that P. simulans occurs as a pest of Brachiaria from Mexico to Colombia. We also studied the levels and mechanisms of resistance present in 34 Brachiaria hybrids developed by CIAT. Infestations were made with six eggs per plant. We used 10 replications (plants) per genotype in a completely randomized design. Seven hybrids were found to be susceptible, 16 showed intermediate resistance and 11 were resistant. Antibiosis was the mechanism of resistance expressed in resistant hybrids as well as in the resistant checks CIAT 6294 and CIAT 36062. Tolerance was absent. The genotypes BRX 4402 and CIAT 0606 were classified as highly susceptible.

Prosapia simulans (Walker) es una especie de salivazo que ataca los pastos del género Brachiaria (Trin.) Griseb. desde México hasta Colombia y ocasiona pérdidas económicas a la industria ganadera. El desarrollo de cultivares resistentes es considerado el mejor método de control del salivazo. Este trabajo tuvo los siguientes objetivos: corroborar la identificación de P. simulans originarias de México y Colombia, probar nuevos híbridos de Brachiaria por resistencia a esta especie y caracterizar los mecanismos de resistencia presentes en ellos. Mediante la combinación de caracteres morfológicos (uso de claves taxonómicas, disección de la genitalia del macho) y técnicas moleculares (RAPD-PCR) se logró corroborar que P. simulans es plaga de Brachiaria spp. desde México hasta Colombia. Para probar híbridos de Brachiaria y caracterizar los mecanismos de resistencia se realizó un ensayo de selección donde se sometieron 34 híbridos al ataque del salivazo. La metodología utilizada fue desarrollada en el CIAT. En el ensayo se infestó con seis huevos maduros de la especie P. simulans por planta. Se usaron diez repeticiones por genotipo en un diseño completamente al azar. En el ensayo de selección de los híbridos se detectaron siete híbridos susceptibles, 16 con resistencia intermedia y 11 resistentes. El mecanismo de resistencia que se expresó en los híbridos resistentes y en los testigos CIAT 6294 y CIAT 36062 fue el de antibiosis. BRX 4402 y CIAT 0606 fueron clasificados como muy susceptibles.

We studied the population fluctuation of nymphs, adults, eggs and natural enemies of the spittlebug Zulia carbonaria(Lallemand) (Homoptera: Cercopidae) associated with Brachiaria dictyoneura pastures of the Cauca River Valley, Colombia. Our objective was to describe spittlebug phenology under seasonal conditions of bimodal precipitation (March-May and September-November). Weekly, over two years, populations of spittlebugs and certain natural enemies were quantified using a sweep net (adults) and counts of nymphs in spittle masses. To obtain eggs and study their development, adult females were collected weekly and placed in petri dishes with moist filter paper to oviposit. In both survey years 3-4 generations of Z. carbonaria were documented with a mean life cycle of 66 days. Populations were most abundant in the first semester and decreased dramatically over the course of the second semester, even in the rainy months (September-November). Very few diapausing eggs were detected (0.5%). Natural enemies included the nymph predator Salpingogaster nigra Schiner (Diptera: Syrphidae), parasitic mites of adults (Acari: Erythraeidae) and fungi of various genera. Although Z. carbonaria synchronizes its life cycle with the rains of the first semester, no role of diapausing eggs was detected as is common in other spittlebug species under conditions of unimodal precipation. Possible explanations for this synchrony and for the scarcity of the insect under the rainy conditions of the second semester are discussed.

Se estudió la fluctuación poblacional de ninfas, adultos, huevos y enemigos naturales de Zulia carbonaria (Lallemand) (Homoptera: Cercopidae) asociado con pastos de Brachiaria dictyoneura en el valle geográfico del río Cauca, Colombia. El objetivo de este trabajo fue describir la fenología de Z. carbonaria bajo las condiciones estacionales de precipitación bimodal (marzo-mayo y septiembre-noviembre). Semanalmente, durante dos años, se cuantificaron las poblaciones del salivazo y ciertos enemigos naturales mediante pases de jama (adultos) y conteos de ninfas en masas de espuma. Para obtener huevos y estudiar su desarrollo, semanalmente se recolectaron adultos hembras que se pusieron a ovipositar en cajas de petri con papel filtro húmedo en su interior. En ambos años de muestreo se documentaron 3-4 generaciones de Z. carbonaria con un ciclo de vida promedia de 66 días. Las poblaciones fueron más abundantes en el primer semestre y disminuyeron dramáticamente en el transcurso del segundo semestre, aún en los meses lluviosos (septiembre-noviembre). Se encontró muy bajo número de huevos diapáusicos (0.5%). Los enemigos naturales encontrados fueron la mosca depredadora de las ninfas Salpingogaster nigra Schiner (Diptera: Syrphidae), ácaros parasitarios de los adultos (Acari: Erythraeidae) y hongos de varios géneros. Aunque Z. carbonaria sincroniza su ciclo de vida con las lluvias del primer semestre, no se detectó un papel de la diapausa en los huevos como es común en otras especies de salivazo en zonas bajo condiciones unimodales de precipitación. Se discuten posibles explicaciones por esa sincronización y por la escasez del insecto bajo las condiciones lluviosas del segundo semestre.

Duas metodologias para criação de cigarrinhas-das-pastagens são relatadas e avaliadas, utilizando-se Aeneolamia varia (Fabricius) sobre Brachiaria ruziziensis Germ. & Evrard. Desenvolveu-se uma nova unidade de criação em pequena escala para manter a cigarrinha nos seus diferentes estágios de desenvolvimento, e assim promover estudos biológicos dos insetos. A unidade possui uma bandeja de plantas com raízes, que são os locais de alimentação e desenvolvimento das ninfas, junto com uma gaiola para emergência dos adultos contendo plantas e substrato para oviposição e obtenção de ovos. Para produção em larga escala, aperfeiçoou-se um método de criação massal, reduzindo-se os insumos e agilizando-se a produção. A principal característica é uma caixa coberta com raízes e condições de microclima adequados para o desenvolvimento de ninfas. A eficiência de produção de adultos a partir de ovos foi de 45,1%, produzindo 1002 adultos/m² por geração, com um período de desenvolvimento ninfal de 36,1 dias. A emergência de adultos foi de 70,5% em uma semana. Esse método para produção massal é uma ferramenta efetiva para produção de cigarrinhas em larga escala, podendo ser utilizado para estudos como de controle com fungos entopatógenos, resistência da planta hospedeira e outros. São discutidas as possibilidades e necessidades futuras para se melhorar a técnica e ajustá-la a outras espécies de cigarrinhas.

Two methodologies for rearing grass-feeding spittlebugs are described and were evaluated with Aeneolamia varia (Fabricius) on Brachiaria ruziziensis Germ. & Evrard. To promote biological studies, a new small-scale rearing unit was developed to maintain spittlebug life stages in the greenhouse year round. This unit features a plant tray established with roots as feeding sites for nymphal development alongside an adult emergence cage with plants and oviposition substrate for egg collection. For large-scale production, an improved mass-rearing colony was designed to reduce inputs and streamline production. The major feature was a covered box with root and microclimate conditions adequate for nymphal development. Efficiency of adult production from eggs was 45.1%, yield 1002 adults/m² per generation, nymphal development time 36.1 d, and adult emergence 70.5% in a 1-wk period. This mass-rearing method is a more effective tool for reliable and high-level production of spittlebugs for massive screening required for the evaluation of control tactics such as fungal entomopathogens and host plant resistance. The possibilities for further improving these designs and tailoring them to other spittlebug species are discussed.