IRTA Entomology

Cabrils, Spain

IRTA Entomology

Cabrils, Spain
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Gemeno C.,University of Lleida | Laserna N.,University of Lleida | Riba M.,University of Lleida | Valls J.,Biomedical Research Institute IRBLLEIDA | And 2 more authors.
Bulletin of Entomological Research | Year: 2012

Macrolophus pygmaeus is commercially employed in the biological control of greenhouse and field vegetable pests. It is morphologically undistinguishable from the cryptic species M. melanotoma, and this interferes with the evaluation of the biological control activity of M. pygmaeus. We analysed the potential of cuticular hydrocarbon composition as a method to discriminate the two Macrolophus species. A third species, M. costalis, which is different from the other two species by having a dark spot at the tip of the scutellum, served as a control. Sex, diet and species, all had significant effects in the cuticular hydrocarbon profiles, but the variability associated to sex or diet was smaller than among species. Discriminant quadratic analysis of cuticular hydrocarbons confirmed the results of previous molecular genetic studies and showed, using cross-validation methods, that M. pygmaeus can be discriminated from M. costalis and M. melanotoma with prediction errors of 6.75% and 0%, respectively. Therefore, cuticular hydrocarbons can be used to separate M. pygmaeus from M. melanotoma reliably. © 2012 Cambridge University Press.

Castane C.,IRTA Entomology | Bueno V.H.P.,Federal University of Lavras | Carvalho L.M.,EMBRAPA - Empresa Brasileira de Pesquisa Agropecuária | Van Lenteren J.C.,Wageningen University
Biological Control | Year: 2014

Orius laevigatus (Hemiptera: Anthocoridae) is a key predator of thrips and is mass reared in large numbers for use in biological control. The aim of this study was to evaluate the effect of founder population size on the biological and behavioral performance of O. laevigatus over time. Laboratory lines were started from 1, 10 and 50 founder couples from 750 adults collected in the field and their performance was evaluated at the 5th-6th and 10th-11th generations. Adaptation to the captive rearing situation occurred in the 10 and 50 founder couples lines while it failed in the 1 founder couple line. The intrinsic rate of natural increase (rm) increased and the period for doubling the population (D) decreased over the generations in the 10 and 50 founder couples lines, while (rm) decreased and (D) increase in the 1 founder couple line. Also, consumption of Frankliniella occidentalis prey was significantly lower for females from the 1 founder couple line at the 5th generation compared to females from the 10 and 50 founder couples lines. Females of laboratory lines of all founder couples did not respond to odours from thrips infested plants during the 5th and 10th generations, whereas wild females strongly reacted to these odours. We suggest that the lack of reaction to infested plant volatiles may be due to the artificial rearing method where mass reared predators do not experience an infested crop. The results showed that the 1 founder couple line differed from the 10 and 50 founder couples lines, suggesting that bottlenecking had an effect at that level. However, no difference was found between the 10 and 50 founder couples lines which suggest that these founder numbers can be used to start laboratory-reared O. laevigatus lines without a significant loss in quality of its relevant biological characteristics. © 2013 Elsevier Inc.

Castane Cristina C.,IRTA Entomology | Arno J.,IRTA Entomology | Gabarra R.,IRTA Entomology | Alomar O.,IRTA Entomology
Biological Control | Year: 2011

The use of plant-feeding predators for biological pest control has traditionally been neglected, mainly due to the risk of them feeding on crop plants and causing economically significant damage. Yet, these predators offer advantages for biological pest control. They are mostly generalist predators that have an impact on several crop pests. They may also be able to establish on crops early in the growing season, when pests colonize them, and can remain on the target crop when prey is scarce. Therefore, management programs must seek to minimize risks while maximizing benefits. In vegetable crops, most of the literature on zoophytophagous predators has focused on four species: Dicyphus tamaninii, Dicyphus hesperus, Macrolophus pygmaeus and Nesidiocoris tenuis (Heteroptera, Miridae). The capacity of these species to produce crop damage in tomatoes varies. This damage has been related to relative predator-to-prey abundance, with damage increasing at high predator abundances and low prey densities. In this review, we analyze the use of these species in biological control programs and the associated benefits and risks. The differences in the damage caused by the four predatory species examined could not be attributed to either stylet morphology or saliva composition. However, feeding on specific plant structures where they may find the resources required for their development is what probably determines feeding damage. Understanding when and why these predators increase their feeding on plants or on certain plant parts is of crucial importance for integrating them in biological control programs. © 2011 Elsevier Inc.

Carvalho L.M.,Empresa de Pesquisa Agropecuaria de Minas Gerais | Bueno V.H.P.,Federal University of Lavras | Castane C.,IRTA Entomology
Journal of Applied Entomology | Year: 2011

Orius species are important biological control agents of thrips in protected crops. Rearing conditions in mass production facilities may affect their performance in the crop when searching for the target prey. The aim of this study was to evaluate and compare the search behaviour and orientation towards prey of two Orius species, O.laevigatus (Fieber) and O. insidiosus (Say) that have been reared in the laboratory under different conditions, with wild (field-collected) individuals. Adult predator females were placed in a Y-tube olfactometer and offered a choice between the odours released by plants of different species (cotton, common bean, sweet pepper and cucumber), which were either non-infested or infested with Frankliniella occidentalis (Pergande) adults.O. laevigatus and O. insidiosus responded to odours from thrips-infested plants and these responses were influenced by the origin of the colonies. A larger percentage of laboratory-reared O. laevigatus females (42%) did not made a choice between thrips-infested or clean plants, compared with wild individuals (17%). Of those females that did respond to plant odours, a smaller percentage of laboratory-reared O. laevigatus females (34%) responded to the odours from thrips-infested plants compared with wild insects (76%). No significant differences were found inO.insidiosus females that did not make a choice between thrips-infested or clean plants (14% for wild vs. 17% for lab individuals). Also, no significant differences were found between O. insidiosus females that selected thrips-infested plants at the corresponding proportion of wild (75%) and laboratory-reared (70%) individuals. We propose that the olfactometer test could be a complementary evaluation aspect to the already developed quality criteria for performance of mass-reared Orius predators. © 2010 Blackwell Verlag, GmbH.

Franco K.,IRTA Entomology | Jauset A.,University of Lleida | Castane C.,IRTA Entomology
Journal of Insect Physiology | Year: 2011

Multiple mating in females is widespread among insects in spite of the risk of predation, disease acquisition and/or physical injury that may occur. One common consequence of female polyandry is competition among sperm from two or more males within the female to fertilize the ova. This competition is an evolutionary driving force that determines a series of adaptations in both males and females. In this work, we examine some behavioral, morphological and physiological characteristics of males and females of two Heteropteran species that are related to their monoandrous/polyandrous mating behavior. Females of Macrolophus pygmaeus (Het. Miridae), the monoandrous species, were coy about accepting a male partner, spent a short time in copula, and received only a small volume of ejaculate. Even so, with only one mating event, they received enough sperm to fertilize most of their ova (21 days after mating all females were still fertile). In contrast, females of Nesidiocoris tenuis (Het. Miridae), the polyandrous species, readily accepted any mating partner, spent a long time in copula and received a large volume of ejaculate. However, these latter females soon ran out of sperm and needed to mate periodically in order to maintain a sufficient sperm supply to fertilize their eggs. As predicted, based on current theory (Simmons, 2001b), an increased investment in spermatogenesis was detected in N. tenuis with relation to M. pygmaeus. The males of the polyandrous species had larger accessory reproductive glands, seminal vesicles, testes and sperm cells than those of the monoandrous species. © 2010 Elsevier Ltd.

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