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Raul Narciso C. Guedes - One of the best experts on this subject based on the ideXlab platform.
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Spinosad- and Deltamethrin-Induced Impact on Mating and Reproductive Output of the Maize Weevil Sitophilus zeamais.
Journal of economic entomology, 2018Co-Authors: M. Vélez, Leonardo Morais Turchen, Lorena L. Botina, Wagner Faria Barbosa, Raul Narciso C. GuedesAbstract:Assessments of acute insecticide toxicity frequently focus on the lethal effects on individual arthropod pest species and populations neglecting the impacts and consequences of sublethal exposure. However, the sublethal effects of insecticides may lead to harmful, neutral, or even beneficial responses that may affect (or not) the behavior and sexual fitness of the exposed insects. Intriguingly, little is known about such effects on stored product insect pests in general and the maize Weevil in particular. Thus, we assessed the sublethal effects of spinosad and deltamethrin on female mate-searching, mating behavior, progeny emergence, and grain consumption by maize Weevils. Insecticide exposure did not affect the resting time, number of stops, and duration of mate-searching by female Weevils, but their walking velocity was compromised. Maize Weevil couples sublethally exposed to deltamethrin and spinosad exhibited altered reproductive behavior (walking, interacting, mounting, and copulating), but deltamethrin caused greater impairment. Curiously, higher grain consumption and increased progeny emergence were observed in deltamethrin-exposed insects, suggesting that this pyrethroid insecticide elicits hormesis in maize Weevils that may compromise control efficacy by this compound. Although spinosad has less of an impact on Weevil reproductive behavior than deltamethrin, this bioinsecticide also benefited Weevil progeny emergence, but did not affect grain consumption. Therefore, our findings suggest caution using either compound, and particularly deltamethrin, for controlling the maize Weevil, as they may actually favor this species population growth when in sublethal exposure requiring further assessments. The same concern may be valid for other insecticides as well, what deserves future attention.
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Larval cannibalism and fitness in the stored grain Weevils Sitophilus granarius and Sitophilus zeamais
Journal of Pest Science, 2017Co-Authors: Diego A. Bolívar-silva, Nelsa Maria P. Guedes, Raul Narciso C. GuedesAbstract:Resource limitation is an important determinant of life history and behavior while mediating competition and reproduction among organisms. Discreet and closed systems such as grain kernels and seeds impose drastic restrictions to grain beetles that spend their immature stages within a single kernel selected by their mother. This is the case of internally feeding stored grain beetles, such as the grain Weevils. Female egg-laying decisions and larval competition largely determine resource limitation for such insects where clustered egg distribution and contest competition with larval interference and cannibalism take place. As the clustered eggs within a grain lead to larval competition and conspecific Weevil larvae face each other off during development allowing the emergence of one or two larvae per kernel, we hypothesized that such competition and consequent cannibalism will have fitness consequences for the competing individuals and their offspring. Thus, larvae of the granary Weevil (Sitophilus granarius L.) and the maize Weevil (Sitophilus zeamais Motsch.) were subjected to larval competition with cannibalism, and lack of it, to assess the potential fitness consequence of cannibalism on these non-carnivorous pest species of stored grains. Larval cannibalism reduced developmental time of maize Weevil, but not of granary Weevil. However, such condition led to heavier adult Weevils of both species exhibiting higher reproductive output generating more and better quality progeny than non-cannibal Weevils. These findings indicate direct nutritional benefits of cannibalism to grain Weevils favoring their status of key pest species of stored cereal grains.
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Evidence of horizontal transmission of primary and secondary endosymbionts between maize and rice Weevils (Sitophilus zeamais and Sitophilus oryzae) and the parasitoid Theocolax elegans
Journal of Stored Products Research, 2014Co-Authors: Gislaine A. Carvalho, Alberto S. Corrêa, Luiz Orlando De Oliveira, Raul Narciso C. GuedesAbstract:Abstract Grain Weevils are hosts of two cellular endosymbionts: Wolbachia and “ Sitophilus Primary Endosymbiont” (SPE). Wolbachia is a facultative endosymbiont, while SPE is an obligatory endosymbiont. Both Wolbachia and SPE are transmitted vertically, that is, from mother to offspring. There are circumstances in which transmission occurs among conspecific organisms or organisms of distinct species (horizontal transmission), and both vertical and horizontal transmissions play significant roles in shaping the host's ecology and evolution. We found molecular evidence for the horizontal transfer of Wolbachia between the maize Weevil ( Sitophilus zeamais Motschulsky) and the rice Weevil ( Sitophilus oryzae (L.)) and evidence of horizontal transfer of Wolbachia and SPE between the maize Weevil and the parasitoid Theocolax elegans Westwood (Hymenoptera: Pteromalidae). Using 16S rRNA fragments of both symbionts, we verified the co-existence of two Wolbachia strains in maize Weevil individuals from a Mexican population, one of which is typically from this species, while the other is from rice Weevils. This finding provides evidence of the horizontal transmission of the endosymbiont between maize and rice Weevil and supports the contention of similarity and relatedness between these Weevil species. We also observed 100% similarity of 16S rRNA fragments between Wolbachia and SPE sequenced from the Weevil parasitoid T. elegans and the maize Weevil. This evidence suggests the horizontal transmission of both endosymbionts from the maize Weevil to its parasitoid T. elegans . In addition to the importance of these findings for the ecology and evolution of Weevils, the potential use of endosymbionts in innovative tactics of arthropod pest management in stored products also deserves attention and remains virtually unexplored.
Stephen L. Clement - One of the best experts on this subject based on the ideXlab platform.
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response ofnp mutant of pea pisum sativum l to pea Weevil bruchus pisorum l oviposition and extracts
Journal of Chemical Ecology, 1995Co-Authors: Robert P. Doss, William M Proebsting, Sandra W Potter, Stephen L. ClementAbstract:TheNp mutant of pea (Pisum sativum L.) is characterized by two physiological responses: growth of callus under pea Weevil (Bruchus pisorum L., Coleoptera: Bruchidae) oviposition on pods, and formation of neoplastic callus on pods of indoor-grown plants. Although these two responses are conditioned byNp, they are anatomically and physiologically distinguishable, based on sites of origin, distribution pattern, and sensitivity to plant hormones. Further characterization of the response to extracts of pea Weevil showed that response of excised pods, measured by callus formation, was log-linear, and treatment with as little as 10−4 Weevil equivalents produced a detectable response. Mated and unmated females contained similar amounts of callus-inducing compound(s), and immature females contained significantly less of the compound(s). Female vetch bruchids (Bruchus brachialis F., Coleoptera: Bruchidae), a related species, contained callus-inducing compound(s), but usually less than pea Weevils on a per Weevil basis. Males of both species contained less than 10% of the activity of the mature females. Extracts of female black vine Weevils, a nonbruchid species, did not stimulate callus formation. Based on partitioning and TLC analysis, the biologically active constitutent(s) was stable and nonpolar. Thus, theNp allele probably conditions sensitivity to a nonpolar component of pea Weevil oviposition as a mechanism of resistance to the Weevil.
Yves Mauffette - One of the best experts on this subject based on the ideXlab platform.
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Influence of white pine watering regimes on feeding preferences of spring and fall adults of the white pine WeevilPissodes strobi (Peck)
Journal of Chemical Ecology, 1994Co-Authors: Robert Lavallée, Paul J. Albert, Yves MauffetteAbstract:Spring and fall adults of the white pine Weevil, Pissodes strobi (Peck), were exposed in no-choice and two-choice tests to bark from water-stressed and non-water-stressed white pine ( Pinus strobus L.), which had also been exposed or not exposed to Weevil attack. This experiment demonstrated that the Weevils could discriminate between bark from water-stressed white pine and preferred bark from the nonstressed plants. The Weevils also preferred bark from nonstressed plants that were previously exposed to Weevil damage. Spring and fall adults displayed the same feeding preferences. No sex differences were found in feeding preferences. Less nitrogen, phosphorus, and potassium were found in bark from the nonstressed plants, and the potassium level was higher in damaged plants. We expect that the biological performance of the Weevil should be favored by vigorously growing plants rather than by stressed plants.
Robert P. Doss - One of the best experts on this subject based on the ideXlab platform.
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response ofnp mutant of pea pisum sativum l to pea Weevil bruchus pisorum l oviposition and extracts
Journal of Chemical Ecology, 1995Co-Authors: Robert P. Doss, William M Proebsting, Sandra W Potter, Stephen L. ClementAbstract:TheNp mutant of pea (Pisum sativum L.) is characterized by two physiological responses: growth of callus under pea Weevil (Bruchus pisorum L., Coleoptera: Bruchidae) oviposition on pods, and formation of neoplastic callus on pods of indoor-grown plants. Although these two responses are conditioned byNp, they are anatomically and physiologically distinguishable, based on sites of origin, distribution pattern, and sensitivity to plant hormones. Further characterization of the response to extracts of pea Weevil showed that response of excised pods, measured by callus formation, was log-linear, and treatment with as little as 10−4 Weevil equivalents produced a detectable response. Mated and unmated females contained similar amounts of callus-inducing compound(s), and immature females contained significantly less of the compound(s). Female vetch bruchids (Bruchus brachialis F., Coleoptera: Bruchidae), a related species, contained callus-inducing compound(s), but usually less than pea Weevils on a per Weevil basis. Males of both species contained less than 10% of the activity of the mature females. Extracts of female black vine Weevils, a nonbruchid species, did not stimulate callus formation. Based on partitioning and TLC analysis, the biologically active constitutent(s) was stable and nonpolar. Thus, theNp allele probably conditions sensitivity to a nonpolar component of pea Weevil oviposition as a mechanism of resistance to the Weevil.
Richard L Roehrdanz - One of the best experts on this subject based on the ideXlab platform.
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genetic differentiation of southeastern boll Weevil and thurberia Weevil populations of anthonomus grandis coleoptera curculionidae using mitochondrial dna
Annals of The Entomological Society of America, 2001Co-Authors: Richard L RoehrdanzAbstract:The southeastern boll Weevil, the Mexican boll Weevil, and the thurberia Weevil are considered to be morphologically similar but behaviorally different variants of the same species, Anthonomus grandis Boheman. A polymerase chain reaction (PCR)-amplified 9.2-kb section of the mitochondrial DNA was cleaved with restriction enzymes. RFLPs of Weevils from three cotton growing locations in Texas and one in northeastern Mexico were compared with thurberia Weevil from three sites in Arizona. Six haplotypes were observed in the Texas/Mexico collections and 12 haplotypes were found among the thurberia Weevil. There were no shared haplotypes between these two groups. Polymorphism was observed within the Weevil types. The three thurberia Weevil locations exhibit some geographic isolation and exhibit differences in both the haplotypes present and the relative frequencies of the haplotypes. Only one haplotype was recovered at all three Arizona sites. The Texas/Mexico samples showed less genetic variability with the northern most site having the lowest polymorphism. 52/53 of these Weevils appear to be genetically southeastern boll Weevil. Two haplotypes were shared by all four of these populations and comprised 72% of the insects examined. The range of genetic distances between haplotypes was <0.001–0.022. The Mexican boll Weevil was not explicitly examined; however, three individuals were discovered that appear to represent a genetically distinct third population. One was from Mexico and the other two were from a thurberia Weevil site. These three individuals may represent the Mexican boll Weevil. The results include apparent diagnostic restriction fragment differences between the thurberia Weevil and the southeastern boll Weevil that could be used to help determine whether future Weevils found in Arizona or California cotton are thurberia Weevil, southeastern boll Weevil, or another population of Weevils.
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Genetic Differentiation of Southeastern Boll Weevil and Thurberia Weevil Populations of Anthonomus grandis (Coleoptera: Curculionidae) Using Mitochondrial DNA
Annals of the Entomological Society of America, 2001Co-Authors: Richard L RoehrdanzAbstract:The southeastern boll Weevil, the Mexican boll Weevil, and the thurberia Weevil are considered to be morphologically similar but behaviorally different variants of the same species, Anthonomus grandis Boheman. A polymerase chain reaction (PCR)-amplified 9.2-kb section of the mitochondrial DNA was cleaved with restriction enzymes. RFLPs of Weevils from three cotton growing locations in Texas and one in northeastern Mexico were compared with thurberia Weevil from three sites in Arizona. Six haplotypes were observed in the Texas/Mexico collections and 12 haplotypes were found among the thurberia Weevil. There were no shared haplotypes between these two groups. Polymorphism was observed within the Weevil types. The three thurberia Weevil locations exhibit some geographic isolation and exhibit differences in both the haplotypes present and the relative frequencies of the haplotypes. Only one haplotype was recovered at all three Arizona sites. The Texas/Mexico samples showed less genetic variability with the northern most site having the lowest polymorphism. 52/53 of these Weevils appear to be genetically southeastern boll Weevil. Two haplotypes were shared by all four of these populations and comprised 72% of the insects examined. The range of genetic distances between haplotypes was
