El papel del etileno en la regulación de la maduración del níspero japonés (Eriobotrya japonica Lindl)

[ES] El etileno (C2H4) es una fitohormona reguladora de procesos fisiológicos como la maduración, la senescencia y la abscisión. El papel de esta hormona ha sido ampliamente estudiado en los frutos climatéricos al que se le atribuye una función clave en el control de la maduración de estos frutos. En el caso del níspero japonés (Eriobotrya japonica Lindl), existe una controversia entre autores en cuanto a su comportamiento en la maduración y, por lo tanto, en su clasificación como climatérico o no-climatérico. Con el objetivo de conocer detalladamente la fisiología de la maduración de este fruto y la influencia del etileno en dicho proceso, se realizaron aplicaciones exógenas de ethephon en diferentes estados fenológicos (709 y 801 BBCH) y a diferentes concentraciones (500 y 1000 ppm) y se evaluaron los parámetros de maduración como la coloración, la acidez libre, el contenido en sólidos solubles totales, el diámetro, la cosecha y la producción de etileno. Los resultados obtenidos indicaron que los árboles tratados con ethephon, independientemente de la concentración, época o combinación con otros tratamientos, no mostraron diferencias significativas con los no tratados respecto a los parámetros anteriormente citados. Consecuentemente, la aplicación exógena de un liberador de etileno no consiguió anticipar la maduración de este fruto a diferencia de lo obtenido en otros frutos climatéricos como el caqui. Además, la evolución en la producción de etileno refleja que este fruto tras metabolizar el ethephon aplicado libera inmediatamente etileno, estabilizándose su producción rápidamente con el tiempo, apenas 24 horas, indicando un comportamiento típico de frutos no climatéricos.[EN] Ethylene (C2H4) is a phytohormone that regulates physiological processes such as fruit ripening, senescence and abscission. The involvement of ethylene has been studied extensively in climacteric fruits and it has a key role in the ripening process of these fruits. In the case of loquat fruit (Eriobotrya japonica Lindl), there is some controversy with regards to its ripening pattern, and consequently with its classification as a climacteric or non-climacteric fruit. With the purpose of clarifying the ripening physiology in this fruit and the role of ethylene in this process, exogenous ethephon applications were done at different phenological stages (BBCH 709 and 801) and concentrations (500 and 1000 ppm) and maturity parameters were evaluated as fruit colour, titratable acidity, soluble solids, fruit size, yield and ethylene generation. The results obtained indicate that treated trees with ethephon, independently of concentration, time or combination with other treatments, didn¿t show significant differences against control trees in all the parameters evaluated. Therefore, the exogenous application of an ethylene releaser wasn¿t able to anticipate the maturity of this fruit in contrast to the results obtain in other climacteric fruits as persimmon fruit. Furthermore, ethylene production evolution shows that this fruit releases immediately ethylene after the applied ethephon is metabolized, but 24 hours later this production is stabilized, showing a similar behaviour to that of non-climacteric fruits.Català Oltra, M. (2013). El papel del etileno en la regulación de la maduración del níspero japonés (Eriobotrya japonica Lindl). http://hdl.handle.net/10251/37999Archivo delegad

Remating in Ceratitis capitata sterile males: Implications in sterile insect technique programmes

Sterile insect technique (SIT) is used, among other biological control tools, as a sustainable measure for the management of Ceratitis capitata Wiedemann (Diptera: Tephritidae) in many agricultural regions where this pest can trigger severe economic impacts. The tendency of wild females to remate multiple times has been deeply studied; it has been a common point of controversy when evaluating SIT programmes. Nevertheless, the remating potential of the released sterile males remains unknown. Here, under laboratory conditions, the remating capability of mass-reared sterile males was determined. Wild-type virgin females were offered to sterile males (Vienna-8 strain), which had the opportunity to mate up to four consecutive times. The remating assays were carried out at 24 hr, 48 hr, 4 days and 7 days after the first mating. At the end of each tested time period, males were divided according to their mating response, mated or unmated, and subsequently reused for the next round of mating assays. The frequency of successful remating in each tested time period was obtained. Insemination was confirmed by determining the sperm transfer in mated female spermathecae by quantitative real-time PCR. Our results demonstrate that 73% of the mass-reared sterile males were able to remate 24 hr after the first mating, 55% of which remated again the day after. Close to 25% of the V8 sterile males tended to copulate in all of the four mating opportunities. The qPCR analysis of the spermathecae contents verified an effective transfer of V8 sperm to wild females with every mating; 99% of copulations resulted in sperm transfer. These findings shed light on the remating potential of V8 sterile males, an aspect until now underestimated in many SIT programmes

Covert infection with an RNA virus affects medfly fitness and the interaction with its natural parasitoid Aganaspis daci

With the advent of high-throughput sequencing, large sets of insect-infecting RNA viruses producing apparent asymptomatic infections are being discovered. In the Mediterranean fruit fly (medfly) Ceratitis capitata, an agricultural key pest of a wide range of fruits, 13 different RNA viruses have been described so far. Recent analysis demonstrated a wide distribution of these viruses in different medfly strains collected worldwide, but little is known about the interactions between those viruses and the medfly host. Previous studies suggested that a higher abundance of Ceratitis capitata nora virus (CcaNV) correlated with a shorter lifespan in adults. Here, we investigated the effect of CcaNV on a broad range of parameters related to host fitness and its interaction with other trophic levels. CcaNV purified from a naturally infected medfly strain was added to the larval diet. Pupal weight, adult emergence, flying ability, and longevity were monitored after oral infections. Our results revealed detrimental effects associated with a CcaNV infection in the medfly, in terms of reduced pupal weight and reduced adult longevity. Moreover, we tested the influence of a CcaNV infection in medflies on the parasitism performance of Aganaspis daci, an endoparasitoid used in biological control programs against medflies. Our results showed that A. daci progeny increased when parasitizing on CcaNV-infected larvae. Overall, we proved that covert RNA viruses can impact the insect ecology, directly affecting its insect host biology and indirectly influencing multitrophic interactions

Estudi del cicle biològic de Matsucoccus feytaudi Ducasse (Hemiptera, Matsucoccidae) i els seus enemics naturals a la Comunitat Valenciana

En el present projecte ens plantegem els següents objetius: 1.- Detectar la presència de M.feytaudi en totes les regions de procedència de Pinus pinaster de la Comunitat Valenciana, mitjançant l'ús de la feromona sexual sintètica de l'espècie. 2.- Estudiar el vol dels mascles de M.feytaudi al llarg de l'any en dues zones de la Comunitat Valenciana, conéixer el nombre de generacions anuales i aportar dades sobre la biología de l'espècie. 3.- Conéixer mitjançant les trampes de feromona sexual de la cotxinilla quins són els enemics naturals de M.feytaudi en dites zones i l'abundància relativa de les diferents espècies al llarg de l'any.Català Oltra, M. (2006). Estudi del cicle biològic de Matsucoccus feytaudi Ducasse (Hemiptera, Matsucoccidae) i els seus enemics naturals a la Comunitat Valenciana. Universitat Politècnica de València. http://hdl.handle.net/10251/31433Archivo delegad

Monitoring of Matsucoccus feytaudi (Hemiptera: Matsucoccidae) and its natural enemies in Spain using sticky tapes and pheromone traps

[EN] The maritime pine bast scale, Matsucoccus feytaudi Ducasse (Hemiptera: Matsucoccidae), occurs in the western part of the Mediterranean basin and is a sap sucking insect that feeds only on maritime pine (Pinus pinaster Aiton). It causes damage in SE France and Italy, where it was accidentally introduced. In Spain information is scarce and, moreover, almost nothing is known about the predators of this species. This study was designed to determine the seasonal trends in abundance of M. feytaudi and its major predators, which might help to improve the biological control of this pest in other areas. Natural P. pinaster stands in the Valencian Community (Spain) were surveyed in 2004. In addition, the seasonal trends in abundance of M. feytaudi and its natural enemies were monitored in three stands over a period of three years (2002, 2005 and 2006). The monitoring was carried by wrapping sticky tapes around tree trunks and using delta traps baited with sexual pheromone. The maritime pine bast scale was detected in all the stands surveyed. At almost all the sites surveyed, three species of predators were captured: Elatophilus nigricornis Zetterstedt (Hemiptera: Anthocoridae), Hemerobius stigma Stephens (Neuroptera: Hemerobiidae) and Malachiomimus pectinatus (Kiesenwetter) (Coleoptera: Malachiidae). The presence of M. pectinatus is noteworthy as this is the first record of this species as a possible predator of M. feytaudi. The results show that M. feytaudi, although differing in its phenology depending on the location, is univoltine in the study area. The prepupae, pupae and adults of M. feytaudi appeared between December and March in colder areas and between October and February in warmer areas. E. nigricornis nymphs are important predators of M. feytaudi, and were abundant when the scale insect (crawlers, prepupae, pupae, male and female adults) was present. The flight period of E. nigricornis and the hemerobiid H. stigma ranged from May to October. However, these flight patterns did not correlate with the presence of the different stages of the bast scale (crawlers, prepupae, pupae, male and female adults) on the surface of tree trunks. The presence of M. pectinatus in large numbers in some stands suggests it might be an important natural regulator, which helps to keep M. feytaudi populations at low densities in the areas of Spain studied. This malachiid shows a strong kairomonal attraction to the sexual pheromone of M. feytaudi and its flight activity is significantly correlated with the presence of crawlers of bast scaleThis research was supported by the Universitat Politècnica de València Vicerrectorado de Innovación y Desarrollo (20060237).Rodrigo Santamalia, ME.; Català Oltra, M.; Pérez Laorga, E.; Baena, M. (2013). Monitoring of Matsucoccus feytaudi (Hemiptera: Matsucoccidae) and its natural enemies in Spain using sticky tapes and pheromone traps. European Journal of Entomology. 110(2):301-310. http://hdl.handle.net/10251/81499S301310110

Liberación de machos estériles de Ceratitis capitata Wiedemann (Diptera: Tephritidae) como vectores de enfermedad causada por hongos entomopatógenos sobre las poblaciones silvestres

Desde el año 2007, la Técnica del Insecto Estéril (TIE) es el principal medio de lucha del Plan de Acción de la Conselleria de Agricultura contra la mosca mediterránea de la fruta Ceratitis capitata Wiedemann (Diptera: Tephritidae) en la Comunitat Valenciana. Esta técnica consiste en la cría masiva de insectos macho de la misma especie a combatir que, tras ser esterilizados, se liberan al campo en grandes cantidades para que copulen con las hembras silvestres, siendo los huevos puestos por éstas infértiles