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Groot A.T.,Max Planck Institute for Chemical Ecology | Groot A.T.,University of Amsterdam | Classen A.,Max Planck Institute for Chemical Ecology | Inglis O.,North Carolina State University | And 6 more authors.
Molecular Ecology | Year: 2011

The two moth species Heliothis virescens (Hv) and H. subflexa (Hs) are closely related, but have vastly different feeding habits. Hv is a generalist and an important pest in many crops in the USA, while Hs is a specialist feeding only on plants in the genus Physalis. In this study, we conducted a comparative population genetic analysis to assess whether and how generalist and specialist life styles are reflected in differences in population structures. In Hv 98% of the total variation occurred within populations. The overall differentiation (FST) between regions was 0.006 and even lower between years (0.0039) and hosts (0.0028). Analyses of population structure suggest that all individuals form one genetically homogeneous population, except for at most 12 individuals (6%) that diverged from this cluster. Population homogeneity likely results from the high mobility of Hv and its generalist feeding behaviour. Hs exhibited substantially more population structure. Even though 96% of the total variation was attributable to within-population variability, F ST-values between Hs populations were 10 times higher than between Hv populations. Hs populations showed significant isolation by distance. Analyses of Hs population structure suggest at least two subpopulations and thus some degree of metapopulation structure. We speculate that the patchy distribution of Physalis- the exclusive food source of Hs - contributes to differences in population structure between these closely related species. The finding that the specialist shows more population differentiation than the generalist corroborates the notion that host specialization is not an evolutionary dead end but a dynamic trait. © 2011 Blackwell Publishing Ltd.

Teran-Vargas A.P.,Campo Experimental Las Huastecas | Azuara-Dominguez A.,Colegio de Mexico | Vega-Aquino P.,Campo Experimental Las Huastecas | Zambrano-Gutierrez J.,Colegio de Mexico | Blanco-Montero C.,U.S. Department of Agriculture
Southwestern Entomologist | Year: 2012

Scyphophorus acupunctatus Gyllenhal causes economic losses to plants of the Agavaceae and Dracaenaceae families and, recently, in commercial plantations of nardo, Polianthes tuberosa L. Synthetic insecticides are the main controls, but these pesticides may not be effective, because larvae and adults are frequently found feeding in the interior of the "ball" of agave plants, far from the reach of the insecticide. The efficacy of insecticides to control this pest is unknown. In this study, we evaluated the effectiveness of synthetic insecticides of different toxicological groups to control S. acupunctatus. The experimental design was completely randomized. The number of dead adults was analyzed using a nonparametric variance of Kruskal Wallis. The percentages of biological effectiveness of insecticides in each bioassay were obtained by using the Abbott formula. Malathion, endosulfan, methomyl, and fipronil showed high biological efficacy. Conversely, cypermethrin, lambda-cyhalothrin, deltamethrin, and betacifluthrin, of constant use in Tamaulipas to control S. acupunctatus, produced a minor effect similar to the nontreated check. However, although some insecticides were effective, it is recommended they be rotated with insecticides with different modes of action or in conjunction with other controls such as food attractants, entomopathogenic fungi and nematodes, and aggregation pheromones, to obtain better control of S. acupunctatus and prevent development of resistance to insecticide.

Azuara-Dominguez A.,Colegio de Mexico | Cibrin-Tovar J.,Colegio de Mexico | Tern-Vargas A.P.,Campo Experimental Las Huastecas | Tafoya-Rangel F.,Autonomous University of Aguascalientes | And 2 more authors.
Southwestern Entomologist | Year: 2012

To trap the agave weevil, Scyphophorus acupunctatus Gyllenhal, tissue of Agave tequilana F.A.C. Weber var. 'azul' and the synthetic pheromone 2-methyl-4-octanone were used. This study evaluated the efficacy of the fermented "pineapple" or "head" of A. tequilana. We also identified volatile compounds attractive to the agave weevil. In the field, between August 2009 and December 2011, we evaluated the following treatments: 1) pheromone, 2) pheromone + fermented agave head, 3) pheromone + non-fermented agave head, 4) fermented agave head, 5) non-fermented agave head, and control (water + insecticide). The volatiles were sampled using the technique of solid-phase microextraction and identified with a gas Chromatograph coupled to a mass selective detector. The traps baited with the pheromone and fermented agave head caught more weevils than did the other treatments. The fermented agave head increased the attraction of S. acupunctatus, while the non-fermented agave head did not contribute significantly. The following volatiles were identified in the fermented agave head: ethyl acetate, ethanol, 2-butanol, and acetic acid. In the non-fermented agave head, 24 volatile compounds were collected, and they were different than those identified in the fermented head. The results obtained indicated that the fermented material was a viable alternative to optimize trapping of S. acupunctatus, because the liberated volatile chemical compounds of the attractant captured a greater number of weevils in the field.

Dominguez A.A.,Altamira Institute of Technology | Vargas A.P.T.,Campo Experimental Las Huastecas | Sandoval A.S.,National Autonomous University of Mexico | Paniagua N.Y.A.,National Autonomous University of Mexico | Bolanos L.M.,National Autonomous University of Mexico
Entomotropica | Year: 2014

In order to establish a trapping program for the agave weevil (Scyphophorus acupunctatus Gyllenhal) in Tamaulipas, Mexico, were evaluated three types of traps (tray, carafe and stake) in combination with food attractants (molasses and agave tequila) and pheromone aggregation. The treatments were evaluated from January to December 2010. The specimens captured were sexed to determine if the sex of S. acupunctatus influences in the trapping. The trap type carafe was the best design in the capture of S. acupunctatus (F = 85.7, df = 2, P = 0.0001). The combination of food bait (molasses and fermented agave) and aggregation pheromone trap type incorporated into the carafe was the best combination to attract adults of S. acupunctatus. The potential use of female trapping of S. acupunctatus using food attractants and aggregation pheromone is discussed. © 2014, Sociedad Venezolana de Entomología.

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