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Fouad Sayah - One of the best experts on this subject based on the ideXlab platform.

  • dietary effects of harmine a β carboline alkaloid on development energy reserves and α amylase activity of Plodia interpunctella hubner lepidoptera pyralidae
    Saudi Journal of Biological Sciences, 2012
    Co-Authors: Noureddin Bouayad, Mostafa Lamhamdi, Naima Ghailani Nourouti, Kacem Rharrabe, Fouad Sayah
    Abstract:

    The physiological and developmental effects of harmine, a β-carboline alkaloid, on the insect pest Plodia interpunctella have been analyzed. When added at the larval diet, harmine induced a strong reduction of larvae weight, cannibalism between larvae, in addition to significant mortality. On the other hand, it caused a remarkable development disruption, manifested by both delay and reduction of pupation and adult emergence. Using spectrophotometric assays, we have shown that harmine ingestion provoked a severe reduction in protein, glycogen and lipid contents. Beside, when larvae fed harmine, the activity of the digestive enzyme α-amylase was strongly reduced. In conclusion, our experiments clearly show the susceptibility of P. interpunctella to harmine ingestion revealing the potent bioinsecticidal effect of harmine.

  • gustatory perception of phytoecdysteroids in Plodia interpunctella larvae
    Entomologia Experimentalis Et Applicata, 2011
    Co-Authors: Kacem Rharrabe, Fouad Sayah, Frederic Marionpoll
    Abstract:

    Phytoecdysteroids are steroidal compounds produced by various plants that disrupt growth and development of insects eating them. They exhibit an insecticidal activity on a number of insect pests such as Plodia interpunctella (Hubner) (Lepidoptera: Pyralidae). In this study, we further evaluated whether phytoecdysteroids deter larvae of this species from feeding, by using four phytoecdysteroid molecules, commonly occurring in plants: 20-hydroxyecdysone (20E), ponasterone A (PonA), polypodine B (PolB), and makisterone A (MakA). Fourth instar P. interpunctella avoided contact with food pellets treated with these phytoecdysteroids in a dose-dependent way (2-30 mM). In order to test whether this avoidance was mediated by taste sensitivity, we recorded the responses of taste neurons located in the lateral and medial sensilla styloconica of the galea. At least one neuron responded to each of these compounds in both sensilla. The neuron located in the medial sensillum had a detection threshold of 10 -6 M for PonA, 10 -4 M for 20E and PolB, and 10 -3 M for MakA. The lateral sensillum neuron responded with less intensity and its detection threshold was 10 times higher than that of the medial sensillum neuron. These results indicate that phytoecdysteroids are detected as deterrent stimuli by P. interpunctella larvae and that small structural differences significantly affect their biological activity.

  • dietary effects of four phytoecdysteroids on growth and development of the indian meal moth Plodia interpunctella
    Journal of Insect Science, 2010
    Co-Authors: Kacem Rharrabe, Fouad Sayah
    Abstract:

    Using pure phytoecdysteroids isolated from Ajuga iva (L.) Schreber (Lamiales: Lamiaceae) and Silene nutans L. (Caryophyllales: Caryophyllaceae), plants known for their high ecdysteroid content, a study was carried out on the effects of ingestion of four different phytoecdysteroids (20-hydroxyecdysone, polypodine B, ponasterone A and makisterone A) on the growth and development of the Indian meal moth, Plodia interpunctella Hubner (Lepidoptera: Pyralidae) larvae when added at a concentration of 200 ppm in their diet. The experiments clearly showed the susceptibility of P. interpunctella to phytoecdysteroid ingestion. The toxicity of phytoecdysteroids manifested itself by a decrease in larval weight, induction of cannibalism and an increase of mortality, together with disruption of development. The severity of the phytoecdysteroid effect on P. interpunctella depended on the structure of the molecule. The results demonstrate that the minimal structural differences existing between these four phytoecdysteroids significantly affected their toxicity toward P. interpunctella. Makisterone A was the most toxic of the four compounds towards P. interpunctella larvae. In conclusion, phytoecdysteroids ingestion evokes disruptive growth effects on P. interpunctella. This work supports a role for phytoecdysteroids in plant defence against phytophagous insects.

  • effects of ingested 20 hydroxyecdysone on development and midgut epithelial cells of Plodia interpunctella lepidoptera pyralidae
    Pesticide Biochemistry and Physiology, 2009
    Co-Authors: Kacem Rharrabe, Noureddin Bouayad, Fouad Sayah
    Abstract:

    We describe the effects of ingested 20-hydroxyecdysone on larvae of Plodia interpunctella. It caused significant mortality and provoked cannibalism between larvae. On the other hand, it also induced precocious pupation and adult emergence. A large weight loss of larvae was recorded. Besides, 20-hydroxyecdysone provoked a reduction in protein, glycogen and lipid contents. Using electron microscopy, we have shown that 20-hydroxyecdysone caused a dose-dependent severe cytotoxicity on the midgut epithelial cells, resulting in the disorganization and the vacuolization of the cytoplasm; the nucleus appeared with crenulated envelope and presented many clear areas between the chromatin clumps and finally, the disruption of microvilli and the rupture of the plasma membrane led to the shedding of cytoplasm contents into the midgut lumen. In conclusion, ingested 20-hydroxyecdysone shows potent growth disruptive effects on P. interpunctella.

  • effects of azadirachtin on post embryonic development energy reserves and α amylase activity of Plodia interpunctella hubner lepidoptera pyralidae
    Journal of Stored Products Research, 2008
    Co-Authors: Kacem Rharrabe, Haitam Amri, Noureddin Bouayad, Fouad Sayah
    Abstract:

    Abstract The effects of azadirachtin on the fourth instar larvae of Plodia interpunctella (Lepidoptera) were investigated. When incorporated into the diet at 2 and 4 ppm, azadirachtin provoked larval weight loss, developmental delay and high larval and pupal mortality. Spectrophotometric assays showed that azadirachtin caused a severe reduction in protein, glycogen and lipid contents 7 days after the beginning of the treatment. In addition, α -amylase activity was reduced in larvaefed azadirachtin.

David J. Thompson - One of the best experts on this subject based on the ideXlab platform.

  • transmission of Plodia interpunctella granulosis virus does not conform to the mass action model
    Journal of Animal Ecology, 1998
    Co-Authors: Robert J Knell, Michael Begon, David J. Thompson
    Abstract:

    1.  Transmission of insect pathogens is traditionally described by a term which states that transmission is proportional to the densities of the susceptible hosts and the infectious units, multiplied by a constant, the transmission coefficient. Theoretical studies suggest that deviations from this can be important in host–pathogen population dynamics, but little is known of how commonly pathogen transmission conforms to the conventional model. 2.  We describe a test of the traditional assumption for the Indian meal moth, Plodia interpunctella (Lepidoptera: Pyralidae) (Hubner) and its granulosis virus using a modification of the previous methods, which allows for unpredictable declines in the amount of infectious material present. 3.  The estimated transmission coefficient increased with the density of susceptible hosts and showed a marked decline with density of infectious cadavers. This suggests that the usual assumption does not adequately describe transmission in this system. 4.  The reasons for this deviation from the usual assumption are likely to be a combination of behavioural and physiological changes at high host density, and differential susceptibility to the pathogen leading to an effect analogous to pseudo-interference in parasitoids.

  • Parasitism of baculovirus-infected Plodia interpunctella by Venturia canescens and subsequent virus transmission
    Functional Ecology, 1996
    Co-Authors: Steven M. Sait, Michael Begon, David J. Thompson, Jeffrey A. Harvey
    Abstract:

    1. When parasitoids and pathogens compete for the same host there are often severe costs to the parasitoid. Wasps might be expected, then, to avoid parasitizing pathogen-infected hosts. 2. When the solitary endoparasitoid Venturia canescens was presented with healthy and granulosis virus-infected larvae of the Indian Meal Moth Plodia interpunctella, it did not exhibit any difference in contact or probing behaviour between healthy and infected hosts. 3. However, oviposition behaviour was influenced by the level of infection, with a significant reduction in the number of eggs laid in heavily infected hosts. 4. Transmission of the pathogen did not occur directly through oviposition. However, transmission through contamination of the environment by the parasitoid following oviposition in infected hosts was demonstrated.

  • transmission dynamics of bacillus thuringiensis infecting Plodia interpunctella a test of the mass action assumption with an insect pathogen
    Proceedings of The Royal Society B: Biological Sciences, 1996
    Co-Authors: Robert J Knell, Michael Begon, David J. Thompson
    Abstract:

    Central to theoretical studies of host-pathogen population dynamics is a term describing transmission of the pathogen. This usually assumes that transmission is proportional to the density of infectious hosts or particles and of susceptible individuals. We tested this assumption with the bacterial pathogen Bacillus thuringiensis infecting larvae of Plodia interpunctella , the Indian meal moth. Transmission was found to increase in a more than linear way with host density in fourth and fifth instar P. interpunctella , and to decrease with the density of infectious cadavers in the case of fifth instar larvae. Food availability was shown to play an important part in this process. Therefore, on a number of counts, the usual assumption was found not to apply in our experimental system.

  • long term population dynamics of the indian meal moth Plodia interpunctella and its granulosis virus
    Journal of Animal Ecology, 1994
    Co-Authors: Steven M. Sait, Michael Begon, David J. Thompson
    Abstract:

    1. Theoretical studies suggest that disease may play an important role in the population dynamics of insects, but there have been no long-term empirical studies that have examined this interaction in the absence of other important biotic and abiotic factors. 2. In the laboratory, three virus-free (VF) populations of Plodia interpunctella were compared with three virus-infected (VI) populations that were continuously exposed to a granulosis virus. Data sets lasted for between 10 and 17 generations. Census data of dead adults were collected twice weekly and spectral analysis of the data was used to complement the observed population fluctuations

  • the effects of a sublethal baculovirus infection in the indian meal moth Plodia interpunctella
    Journal of Animal Ecology, 1994
    Co-Authors: Steven M. Sait, Michael Begon, David J. Thompson
    Abstract:

    1. Baculoviruses are often highly pathogenic to their insect hosts, but theoretical studies have shown that sublethal infections may also play an important role in host population dynamics. Previous experiments have suggested that deleterious effects are caused by sublethal infections in a number of host-pathogen interactions, but these studies have been criticized on the basis of the methodology used. 2. Using an improved bioassay technique, the dose- and age-dependent response of the Indian meal moth, Plodia interpunctella, to sublethal levels of its granulosis virus was investigated. For the first time, significant sublethal effects have been unequivocally demonstrated in the development rate and reproductive capacity of the host

Christer Löfstedt - One of the best experts on this subject based on the ideXlab platform.

  • experience influences oviposition behaviour in two pyralid moths ephestia cautella and Plodia interpunctella
    Animal Behaviour, 2006
    Co-Authors: P Christian O Olsson, Olle Anderbrant, Christer Löfstedt
    Abstract:

    We investigated the importance of experience for oviposition behaviour in two pyralid moths, the almond moth, Ephestia cautella, and the Indian meal moth, Plodia interpunctella. We used two diets one based on wheat and the other consisting of nut-containing chocolate. Larvae were reared in one of the two diets (larval feeding) and then adults were exposed to the two diets during and after eclosion (pre-exposure). Larval feeding had an enhancing effect on the subsequent oviposition behaviour in E. cautella females, but not in P. interpunctella. This shows that the Hopkins' host selection principle to some extent applies in E. cautella. The pre-exposure strongly reinforced the ovipositional response to the previously encountered diet in both species. This effect might be caused by imprinting of the surrounding conditions in the females while emerging, and by stimulated oviposition when the imprinted cues are recognized by the gravid females. We observed both host location (flight) and host acceptance (oviposition), and the effect of experience was most prominent in the host acceptance step of the host selection behaviour. Since host acceptance is believed to be the most crucial decision step for offspring viability, this distinction was expected.

  • flight and oviposition behavior of ephestia cautella and Plodia interpunctella in response to odors of different chocolate products
    Journal of Insect Behavior, 2005
    Co-Authors: P Christian O Olsson, Olle Anderbrant, Christer Löfstedt
    Abstract:

    The present study is included in a project with the aim to develop attractants from food odors for trapping female moths. Males and mated, but not unmated, females of Ephestia cautella and Plodia interpunctella were attracted by odors of three different chocolate products in flight tunnel experiments. Chocolate containing nut or rum elicited upwind flight and landing responses. Extracts of the chocolate products induced upwind flight in both species and both sexes. Larvae of the tested species survived best in plain chocolate (E. cautella) or nut-containing chocolate (P. interpunctella). The oviposition preference of P. interpunctella females seems to be highly adaptive, since females oviposited in the diet most suitable for larval feeding, whereas E. cautella females showed a less selective oviposition preference, between the diets tested.

  • disruption of the odour mediated mating behaviour of Plodia interpunctella using high frequency sound
    Entomologia Experimentalis Et Applicata, 2003
    Co-Authors: Glenn P. Svensson, Niels Skals, Christer Löfstedt
    Abstract:

    Indian meal moths, Plodia interpunctella Hubner (Lepidoptera: Pyralidae), have ears which are sensitive to high-frequency calls produced by echolocating, insectivorous bats. The influence of artificially generated, high-intensity, ultrasound signals (25 kHz, 106 dB SPL at 1 m distance) on different parameters involved in the odour-mediated mating behaviour of this species and its potential use in population control was investigated. All moths flying towards olfactory cues in flight tunnel experiments reacted strongly to a 1 s ultrasound pulse by cessation of flight and falling out of the odour plume. The source contact proportion of both male moths orienting towards the female-produced sex pheromone and of mated female moths orienting towards an oviposition cue was reduced by 40%, compared to unexposed moths. Calling females responded to the sound by retraction of the ovipositor or by falling to the ground. Long-term exposure to repetitive pulses of ultrasound suppressed female calling by up to 27%. Furthermore, mating in plastic tents was disrupted by up to 58% in ultrasound-treated tents using different sound regimens, compared to control tents. The results are discussed in relation to the potential use of ultrasound technology for the population control of pyralid stored product pests.

  • mating disruption of Plodia interpunctella in small scale plots effects of pheromone blend emission rates and population density
    Journal of Chemical Ecology, 2001
    Co-Authors: Camilla Ryne, Glenn P. Svensson, Christer Löfstedt
    Abstract:

    An indoor mating disruption experiment was performed on the stored-product pest Plodia interpunctella. The female of this species emits a four-component pheromone blend consisting of Z9,E12–14 : OAc, Z9,E12–14 : OH, Z9,E12–14 : Ald, and Z9–14 : OAc. Mating of Plodia interpunctella was disrupted up to 93% by using synthetic pheromone in small-scale plot experiments. The study was performed in 2.5 m × 2.5 m × 2.5 m polythene cubicles housed in a greenhouse, and pheromones were released by MSTRS spraying every 15~min. The disruption effect was tested at different doses 0.075, 0.75, and 3.75 mg/spray (corresponding to 5, 50, and 250 μg/min), different pheromone formulas (one-component (Z9,E12–14 : OAc) and four-component), and at different population densities (10, 20, and 30 individuals, equivalent to 0.32, 0.64, and 0.96 individuals/m2). The moths were released into the cubicles and recaptured 24 hr later. The females were checked for spermatophore presence indicating successful mating. The mating was significantly suppressed in all treatments compared to the control. There was, however, no difference in mating activity between the one-component and four-component disruptants. In addition, EAG measurements were conducted with a portable device to keep track of aerial concentrations of pheromone. The results show that the one-component formula disrupts mating as efficiently as the more complete four-component blend at doses applied in this study. This fact improves the prospects for mating disruption of indoor pyralids, since many pyralid species share the major component in their pheromones, and, thus, can probably be controlled simultaneously by using this compound only.

Kacem Rharrabe - One of the best experts on this subject based on the ideXlab platform.

  • dietary effects of harmine a β carboline alkaloid on development energy reserves and α amylase activity of Plodia interpunctella hubner lepidoptera pyralidae
    Saudi Journal of Biological Sciences, 2012
    Co-Authors: Noureddin Bouayad, Mostafa Lamhamdi, Naima Ghailani Nourouti, Kacem Rharrabe, Fouad Sayah
    Abstract:

    The physiological and developmental effects of harmine, a β-carboline alkaloid, on the insect pest Plodia interpunctella have been analyzed. When added at the larval diet, harmine induced a strong reduction of larvae weight, cannibalism between larvae, in addition to significant mortality. On the other hand, it caused a remarkable development disruption, manifested by both delay and reduction of pupation and adult emergence. Using spectrophotometric assays, we have shown that harmine ingestion provoked a severe reduction in protein, glycogen and lipid contents. Beside, when larvae fed harmine, the activity of the digestive enzyme α-amylase was strongly reduced. In conclusion, our experiments clearly show the susceptibility of P. interpunctella to harmine ingestion revealing the potent bioinsecticidal effect of harmine.

  • gustatory perception of phytoecdysteroids in Plodia interpunctella larvae
    Entomologia Experimentalis Et Applicata, 2011
    Co-Authors: Kacem Rharrabe, Fouad Sayah, Frederic Marionpoll
    Abstract:

    Phytoecdysteroids are steroidal compounds produced by various plants that disrupt growth and development of insects eating them. They exhibit an insecticidal activity on a number of insect pests such as Plodia interpunctella (Hubner) (Lepidoptera: Pyralidae). In this study, we further evaluated whether phytoecdysteroids deter larvae of this species from feeding, by using four phytoecdysteroid molecules, commonly occurring in plants: 20-hydroxyecdysone (20E), ponasterone A (PonA), polypodine B (PolB), and makisterone A (MakA). Fourth instar P. interpunctella avoided contact with food pellets treated with these phytoecdysteroids in a dose-dependent way (2-30 mM). In order to test whether this avoidance was mediated by taste sensitivity, we recorded the responses of taste neurons located in the lateral and medial sensilla styloconica of the galea. At least one neuron responded to each of these compounds in both sensilla. The neuron located in the medial sensillum had a detection threshold of 10 -6 M for PonA, 10 -4 M for 20E and PolB, and 10 -3 M for MakA. The lateral sensillum neuron responded with less intensity and its detection threshold was 10 times higher than that of the medial sensillum neuron. These results indicate that phytoecdysteroids are detected as deterrent stimuli by P. interpunctella larvae and that small structural differences significantly affect their biological activity.

  • dietary effects of four phytoecdysteroids on growth and development of the indian meal moth Plodia interpunctella
    Journal of Insect Science, 2010
    Co-Authors: Kacem Rharrabe, Fouad Sayah
    Abstract:

    Using pure phytoecdysteroids isolated from Ajuga iva (L.) Schreber (Lamiales: Lamiaceae) and Silene nutans L. (Caryophyllales: Caryophyllaceae), plants known for their high ecdysteroid content, a study was carried out on the effects of ingestion of four different phytoecdysteroids (20-hydroxyecdysone, polypodine B, ponasterone A and makisterone A) on the growth and development of the Indian meal moth, Plodia interpunctella Hubner (Lepidoptera: Pyralidae) larvae when added at a concentration of 200 ppm in their diet. The experiments clearly showed the susceptibility of P. interpunctella to phytoecdysteroid ingestion. The toxicity of phytoecdysteroids manifested itself by a decrease in larval weight, induction of cannibalism and an increase of mortality, together with disruption of development. The severity of the phytoecdysteroid effect on P. interpunctella depended on the structure of the molecule. The results demonstrate that the minimal structural differences existing between these four phytoecdysteroids significantly affected their toxicity toward P. interpunctella. Makisterone A was the most toxic of the four compounds towards P. interpunctella larvae. In conclusion, phytoecdysteroids ingestion evokes disruptive growth effects on P. interpunctella. This work supports a role for phytoecdysteroids in plant defence against phytophagous insects.

  • effects of ingested 20 hydroxyecdysone on development and midgut epithelial cells of Plodia interpunctella lepidoptera pyralidae
    Pesticide Biochemistry and Physiology, 2009
    Co-Authors: Kacem Rharrabe, Noureddin Bouayad, Fouad Sayah
    Abstract:

    We describe the effects of ingested 20-hydroxyecdysone on larvae of Plodia interpunctella. It caused significant mortality and provoked cannibalism between larvae. On the other hand, it also induced precocious pupation and adult emergence. A large weight loss of larvae was recorded. Besides, 20-hydroxyecdysone provoked a reduction in protein, glycogen and lipid contents. Using electron microscopy, we have shown that 20-hydroxyecdysone caused a dose-dependent severe cytotoxicity on the midgut epithelial cells, resulting in the disorganization and the vacuolization of the cytoplasm; the nucleus appeared with crenulated envelope and presented many clear areas between the chromatin clumps and finally, the disruption of microvilli and the rupture of the plasma membrane led to the shedding of cytoplasm contents into the midgut lumen. In conclusion, ingested 20-hydroxyecdysone shows potent growth disruptive effects on P. interpunctella.

  • effects of azadirachtin on post embryonic development energy reserves and α amylase activity of Plodia interpunctella hubner lepidoptera pyralidae
    Journal of Stored Products Research, 2008
    Co-Authors: Kacem Rharrabe, Haitam Amri, Noureddin Bouayad, Fouad Sayah
    Abstract:

    Abstract The effects of azadirachtin on the fourth instar larvae of Plodia interpunctella (Lepidoptera) were investigated. When incorporated into the diet at 2 and 4 ppm, azadirachtin provoked larval weight loss, developmental delay and high larval and pupal mortality. Spectrophotometric assays showed that azadirachtin caused a severe reduction in protein, glycogen and lipid contents 7 days after the beginning of the treatment. In addition, α -amylase activity was reduced in larvaefed azadirachtin.

Tao Zhang - One of the best experts on this subject based on the ideXlab platform.