Rhinoncomimus latipes Korotyaev (Coleoptera: Curculionidae), a biological control agent of mile-a-minute weed, Persicaria perfoliata (L.) H. Gross, has been mass reared with no infusion of new ...genetic material for 8-9 yr (at least 24-36 generations), while insects from the same genetic stock have been subject to field conditions in North America for that same period of time. Our main objective was to compare the laboratory population with the field population (and in 1 yr with a Chinese field population) to determine whether genetic changes had occurred, especially ones that may reduce the effectiveness of the laboratory population when released in the field. The laboratory insects laid more eggs and had reduced survival compared with field weevils in several comparisons, and had reduced responsiveness to cues that induce reproductive diapause. Exposure to older plants had the greatest effect on induction of reproductive diapause in both laboratory and field weevils, with effects of daylength and temperature less pronounced. At least a portion of the laboratory weevil population overwintered successfully. Results suggest that it is not necessary to add wild-type genetic material to the rearing colony at this time.
Phlyctinus callosus (Boheman) (Coleoptera: Curculionidae) is a pest of major phytosanitary concern for some of South Africa's biggest export markets such as the United States and Europe because this ...pest does not occur there. At present, fumigation with methyl bromide is the only postharvest disinfestation treatment against this pest; therefore, sustainable alternatives are needed. One such alternative is irradiation treatment of whole pallets of packed fruit to sterilize insects that may be present within the cartons. Wild adult P. callosus weevils were treated with 5, 10, 20, 40, and 80 Gy of gamma -irradiation and then cross mated to breed with either treated or nontreated adults of the opposite sex. Fecundity and fertility were monitored and recorded. Trials were conducted during the 2009-2010 and 2010-2011 fruit harvesting seasons. The results from both seasons indicated that irradiation did not affect fecundity but fertility was significantly affected, decreasing as irradiation doses increased. Egg hatch was zero for mating crosses that involved females weevils treated with a dose of 80 Gy gamma -irradiation. Probit analysis indicated that in the first season, the estimated LD95 for crosses involving treated males and treated females was 30 Gy, while in the second season it was 49.5 Gy. Respective estimated LD99s were 47.9 and 169.4 Gy. Ultimately, a dose lower than the current generic dose of 400 Gy, approved for irradiation disinfestation treatments, would control P. callosus should they occur in packed export fruit.
This Special Issue on the Systematics and Phylogeny of Weevils presents 31 new research papers on one of the most diverse and successful groups of animals on Earth, the beetle superfamily ...Curculionoidea. It was in part inspired to commemorate the extraordinary life and scientific achievements of Guillermo (“Willy”) Kuschel (1918–2017), who shaped this field of science over the last century like no other weevil systematist. The papers in this memorial issue span weevil faunas from all over the globe, including South and Central America, Africa, Europe and the Near East, South-East Asia, New Guinea, Australia and New Zealand. They include major advances on the phylogeny and classification of the “broad-nosed” weevils (Entiminae), on the weevils associated with American cycads and on the unique extinct weevil fauna preserved in the 100-million-year-old Burmese amber, when weevils started to diversify alongside the oldest angiosperm plants. They comprise a tribute to Willy Kuschel, the proceedings of a weevil symposium held in his honor in 2016 in Orlando, Florida, 24 systematic studies (including seven phylogenetic analyses) and five other contributions on the diversity, biology, distribution, evolution and fossil history of weevils. In the papers collated in this volume, 30 new genera and 92 new species of weevils are described and a new family of extinct weevils is recognized.
This Special Issue on the Systematics and Phylogeny of Weevils presents 31 new research papers on one of the most diverse and successful groups of animals on Earth, the beetle superfamily ...Curculionoidea. It was in part inspired to commemorate the extraordinary life and scientific achievements of Guillermo (“Willy”) Kuschel (1918–2017), who shaped this field of science over the last century like no other weevil systematist. The papers in this memorial issue span weevil faunas from all over the globe, including South and Central America, Africa, Europe and the Near East, South-East Asia, New Guinea, Australia and New Zealand. They include major advances on the phylogeny and classification of the “broad-nosed” weevils (Entiminae), on the weevils associated with American cycads and on the unique extinct weevil fauna preserved in the 100-million-year-old Burmese amber, when weevils started to diversify alongside the oldest angiosperm plants. They comprise a tribute to Willy Kuschel, the proceedings of a weevil symposium held in his honor in 2016 in Orlando, Florida, 24 systematic studies (including seven phylogenetic analyses) and five other contributions on the diversity, biology, distribution, evolution and fossil history of weevils. In the papers collated in this volume, 30 new genera and 92 new species of weevils are described and a new family of extinct weevils is recognized.
The Eastern, Western, and Egyptian strains of alfalfa weevil are pests introduced to North America on three separate occasions, now they share partially overlapping geographic ranges, covering most ...of the continental United States. Behavior, susceptibility to parasites, and subtle morphological differences separate the strains. The difficulty in differentiating among these strains morphologically has led to the application of molecular phylogeny approaches including restriction fragment-length polymorphism characterization and sequencing of mitochondrial genes. While valuable for strain identification, this approach cannot identify interstrain hybrids because mitochondrial markers are maternally inherited. The work reported here extends previous findings by comparing over 7 Kb of sequence from two mitochondrial and four nuclear loci to increase the resolution of molecular phylogeny for these weevils. The related clover leaf weevil, also an occasional pest of alfalfa, was included in the analysis because the molecular phylogeny of this weevil has not been examined to date. Analysis of nuclear loci indicate that the clover weevil is a distinct species. Furthermore, while the three alfalfa weevil strains are separable based on mitochondrial sequence data they cannot be separated using nuclear loci suggesting that they are all recently diverged members of the same species. These data refine the relationships among these strains and may find application in design of better control strategies.
Rhyssomatus subtilis Fiedler (Coleoptera: Curculionidae) is an important pest of the soybean crop in northwestern Argentina. Few studies have been made on specific parameters of its life history and ...ecology. The aim of this study was to determine the number of larval stages of R. subtilis. One thousand and eighteen larvae were collected from soybean plants during 2 yr (2011 and 2013), and head capsule width of each larva was measured. For analysis of data, the Hcap program and Dyar's rule were used. The Hcap program showed 4 different peaks in the frequency distribution of the head capsule widths. This result also agreed with Dyar's rule that revealed a perfect geometric larval growth pattern for each instar by regression analysis. The excellent fit to a linear model, indicates that no instar was overlooked. This research identified 4 instars for R. subtilis.
Se describe Rhinusa chaenorhini sp. nov. de varias localidades de España distribuidas de norte a sur de la mitad oriental del territorio. La nueva especie es claramente diferenciable de todas las ...especies del género principalmente por la inusual forma del rostro, el cual esta abruptamente constreñido desde la inserción antenal hasta el ápice, y por la forma del edeago.
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