Evaluación de tres clases de trigo para la cría de Sitotroga cerealella (Lepidoptera: Gelechiidae) como hospedante utilizado en la cría de enemigos naturales

La estandarización de protocolos para la cría artificial es esencial para lograr una producción de insectos adecuada en calidad y cantidad. Los huevos de Sitotroga cerealella Olivier se utilizan para la cría de parasitoides del género Trichogramma. En el presente trabajo se evaluó el efecto de tres tipos de trigo (pan, candeal, Klein Tauro) sobre parámetros biológicos de la polilla y del parasitoide oófago Trichogramma nerudai (Pintureau & Gerding). La cría de la polilla se realizó sobre cada tipo de trigo y sobre los huevos obtenidos se evaluaron aspectos biológicos del parasitoide. Las clases de trigo se diferenciaron en la calidad de sus proteínas, lípidos y contenido de humedad. Para los distintas tipos de trigo se encontraron diferencias significativas en el porcentaje de emergencia, la fecundidad, el tiempo de desarrollo y la proporción sexual de las polillas. No existieron diferencias significativas en el porcentaje de emergencia, fecundidad y proporción sexual de parasitoides criados sobre huevos de polillas procedentes de diferentes clases de trigo. El análisis de aminoácidos y lípidos, los resultados sobre la biología de la polilla y cierta tendencia observada en la fecundidad del parasitoide, sugieren que los trigos más adecuados para la cría son pan y candeal.The development of standard protocols for artificial rearing is essential for a suitable production of insects. The eggs of the wheat moth Sitotroga cerealella Olivier are used to rear the oophagous parasitoids of the genus Trichogramma. In the present work we evaluated the effect of three wheat types (pan, candeal, Klein Tauro) on biological parameters of the moth adults and the parasitoid Trichogramma nerudai (Pintureau & Gerding). Also, the content of proteins, the carbohydrates and the moisture of each wheat type were analyzed. There were significant differences in the emergence, fertility, development time and sexual ratio of moths among wheat classes. No significant differences were found in the emergence, fertility and sex ratio of the parasitoid developed on eggs of moths coming from different classes of wheat. The analysis of amino acids and lipids, the biology of the moth and certain tendency observed in the fecundity of the parasitoid suggest that the most suitable wheat types for rearing these two insects are pan and candeal.Instituto de Microbiología y Zoología AgrícolaFil: Méndez, Lucía M. Instituto Tecnológico de Costa Rica. Centro de Investigaciones en Biotecnología CIB; Costa RicaFil: Botto, Eduardo Norberto. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Microbiología y Zoología Agrícola. Insectario de Investigaciones para Lucha Biológica; ArgentinaFil: Flores, Dora. Instituto Tecnológico de Costa Rica. Centro de Investigaciones en Biotecnología CIB; Costa RicaFil: Cagnotti, Cynthia Lorena. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Microbiología y Zoología Agrícola. Insectario de Investigaciones para Lucha Biológica; ArgentinaFil: Lopez, Silvia Noemi. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Microbiología y Zoología Agrícola. Insectario de Investigaciones para Lucha Biológica; ArgentinaFil: Viscarret, Mariana Mabel. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Microbiología y Zoología Agrícola. Insectario de Investigaciones para Lucha Biológica; Argentin

Whitefly species (Hemiptera: Aleyrodidae) on wild and cultivated plants in the horticultural region of Rosario, Santa Fe, Argentina

Las moscas blancas de importancia económica son polífagas y capaces de desarrollarse sobre numerosas plantas cultivadas y espontáneas. Registramos las especies de moscas blancas sobre cultivos hortícolas y de flores, y sobre las plantas silvestres asociadas. Observamos dos especies: Trialeurodes vaporariorum (Westwood) y el complejo Bemisia tabaci (Gennadius). T. vaporariorum fue registrada sobre 24 especies de plantas (11 familias), 12 y 8 de las cuales son hospedantes nuevos para Argentina y a nivel mundial, respectivamente. El complejo B. tabaci fue registrado solo en sistemas de producción de flores, sobre 19 especies de plantas (11 familias), 14 y 7 de las cuales son nuevos hospedantes para Argentina y a nivel mundial, respectivamente. Los cultivos Glycine max (L.) y Chrysanthemum morifolium Ramat., las especies silvestres Amaranthus blitum L., Amaranthus quitensis Kunth, Conyza bonariensis (L.), Galinsoga parviflora Cav., Sonchus oleraceus L. y Wedelia glauca (Ortega) O. Hoffm. ex Hicken fueron hospedantes de ambas especies. El único parasitoide registrado fue Eretmocerus californicus cercano a corni Haldeman (Hymenoptera: Aphelinidae) sobre T. vaporariorum. Este estudio que constituye el primer relevamiento sistemático de plantas hospedantes en la región, aporta un mayor conocimiento sobre el rango de plantas hospedantes de las moscas blancas en Argentina

Innate Host Habitat Preference in the Parasitoid Diachasmimorpha longicaudata: Functional Significance and Modifications through Learning.

Parasitoids searching for polyphagous herbivores can find their hosts in a variety of habitats. Under this scenario, chemical cues from the host habitat (not related to the host) represent poor indicators of host location. Hence, it is unlikely that naïve females show a strong response to host habitat cues, which would become important only if the parasitoids learn to associate such cues to the host presence. This concept does not consider that habitats can vary in profitability or host nutritional quality, which according to the optimal foraging theory and the preference-performance hypothesis (respectively) could shape the way in which parasitoids make use of chemical cues from the host habitat. We assessed innate preference in the fruit fly parasitoid Diachasmimorpha longicaudata among chemical cues from four host habitats (apple, fig, orange and peach) using a Y-tube olfactometer. Contrary to what was predicted, we found a hierarchic pattern of preference. The parasitism rate realized on these fruit species and the weight of the host correlates positively, to some extent, with the preference pattern, whereas preference did not correlate with survival and fecundity of the progeny. As expected for a parasitoid foraging for generalist hosts, habitat preference changed markedly depending on their previous experience and the abundance of hosts. These findings suggest that the pattern of preference for host habitats is attributable to differences in encounter rate and host quality. Host habitat preference seems to be, however, quite plastic and easily modified according to the information obtained during foraging

X-ray doses to safely release the parasitoid Diachasmimorpha longicaudata (Hymenoptera: Braconidae) reared on Anastrepha fraterculus larvae (Diptera: Tephritidae)

Diachasmimorpha longicaudata is a koinobiont larval parasitoid that is currently used to control fruit flies of the genera Anastrepha, Ceratitis and Bactrocera. In the rearing process, a fraction of the host larvae that are exposed to parasitoids escape from parasitism and develop into viable and fertile flies. This creates the need to eliminate emerging flies before the parasitoids are shipped for release, increasing costs due to additional handling steps. Exposure of fly eggs or larvae to gamma-irradiation before they are parasitised has been used to reproductively sterilise hosts, or even inhibit their emergence. Our aim was to determine whether X-ray radiation applied to Anastrepha fraterculus third instar larvae before they are exposed to parasitoids, inhibits fly emergence in non-parasitised larvae without affecting the performance of the parasitoids that emerge from parasitised larvae. Three X-ray doses: 6250.2 R, 8333.6 R and 10417 R (equivalent to 60, 80 and 100 Gy, respectively) and one γ-ray dose (100 Gy) were tested. Fly emergence decreased with increasing doses of radiation, showing null values for the higher X-ray dose and the dose of 100 Gy. Irradiation showed either no impact or a positive effect on parasitism rate and fecundity. Sex rate was biased towards females in almost every dose. We conclude that the two types of radiation evaluated here were equally effective in suppressing fly emergence with no detrimental effects on the biological quality of the produced parasitoids. X-rays offer an alternative method of irradiation than the conventional radiation source, i.e. γ-rays. These results represent a significant improvement in the development of a biological control programme against A. fraterculus.12 page(s

Quality of different fruit species as foraging substrates.

<p>a) Mean parasitism rate by <i>Diachasmimorpha longicaudata</i> recorded in different fruit species infested by <i>Ceratitis capitata</i> larvae. b) Mean density of larvae offered during infested fruit exposure in experiment 4. Bars show the standard error of the mean.</p

Effect of previous experience on the preference of <i>Diachasmimorpha longicaudata</i> females for different fruit species.

<p>Bars show the number of females (conditioned either on apple or orange) visiting each option in the experiment 3. G-test level of significance: * p < 0.05; ** p < 0.01.</p

Survival curves for adult <i>Diachasmimorpha longicaudata</i> reared on <i>Ceratitis capitata</i> larvae that developed in different host fruit.

<p>Different fruit species are labelled with a different shape: Apple: circles; Fig: squares; Orange: triangles; Peach: diamonds. (a) males and (b) females.</p

Pupal weight (mean ± S.E.) of <i>Ceratitis capitata</i> reared on different fruit species.

<p>Pupal weight (mean ± S.E.) of <i>Ceratitis capitata</i> reared on different fruit species.</p

Preference for different fruit species by <i>Diachasmimorpha longicaudata</i> females in a Y-tube olfactometer.

<p>Bars show the number of females visiting each option in each pair-wise combination among the four fruit species (experiment 1). G-test level of significance: * p < 0.05; ** p < 0.01.</p

Preference of <i>Diachasmimorpha longicaudata</i> females for fruit with different levels of infestation by <i>Ceratitis capitata</i>.

<p>Bars show the number of females visiting each option in the experiment 2. H: high infestation level; L: low infestation level. G-test level of significance: n.s. = non-significant; * p < 0.05; ** p < 0.01. n.s.</p