scholarly journals An Ultrastructural and Fluorescent Study of the Teratocytes ofMicroctonus aethiopoidesLoan (Hymenoptera: Braconidae) from the Hemocoel of Host Alfalfa Weevil,Hypera postica(Gyllenhal) (Coleoptera: Curculionidae)

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Kent S. Shelby ◽  
Javad Habibi ◽  
Benjamin Puttler
Keyword(s):  
Nuclear Envelope ◽  
Fluorescent Dyes ◽  
Alfalfa Weevil ◽  
Hypera Postica ◽  
Complex Cells ◽  
Egg Maturation ◽  
Large Numbers ◽  
Layer Analysis ◽  
Microctonus Aethiopoides ◽  
Braconid Wasp

The braconid waspMicroctonus aethiopoidesLoan is an idiobiont endoparasitoid of alfalfa weevil adultsHypera postica(Gyllenhal). After oviposition and subsequent egg maturation, large trophic cells called teratocytes dissociate from the serosa and are released into the host hemocoel. These teratocytes are present in large numbers and are visible to the naked eye. It is thought that they accumulate host hemocoelic metabolites for later consumption by the parasitoid larvae. We have undertaken a microscopic study of these gargantuan and complex cells at approximately seven months after parasitization. Parasitized adult weevils were dissected into medium and teratocytes were fixed, embedded, and sectioned at 1 μm. Teratocytes were stained with various specific fluorescent dyes for plasma membrane, Golgi, nuclei, lysosomes, mitochondria, and endoplasmic reticulum (ER). The surface of each cell is covered with a dense microvillar layer. Analysis of fluorescent images showed that these cells do not have condensed nuclei. ER was abundant around the nuclear envelope. Lysosomes were positioned around the periphery of the nucleus and the Golgi apparatus was significantly enlarged, being located around the nuclear envelope.

Phenology of the Alfalfa Weevil (Coleoptera: Curculionidae) and its Associated Parasitoids in Minnesota

2000 ◽  
Vol 35 (3) ◽  
pp. 227-238
Author(s):  
Kathy L. Flanders ◽  
Edward B. Radcliffe
Keyword(s):  
First Generation ◽  
Economic Damage ◽  
Alfalfa Weevil ◽  
Seasonal Incidence ◽  
Hypera Postica ◽  
Parasitism Rates ◽  
Southern Half ◽  
Cool Summer ◽  
Low Incidence ◽  
Microctonus Aethiopoides

Field surveys were conducted in Minnesota to determine the seasonal incidence of parasitism of alfalfa weevil, Hypera postica (Gyllenhal), by Bathyplectes curculionis (Thomson), B. anurus (Thomson), Oomyzus (=Tetrastichus) incertus (Ratzeburg), and Microctonus aethiopoides (Loan). During the 1991–1993 survey, alfalfa weevil population density was typically below that required to cause economic damage. In Minnesota, peak density of alfalfa weevil larvae tended to occur around 300 dd (base 9°C). Typically, first cutting of alfalfa in Minnesota occurs early enough to remove most alfalfa weevil before they have completed larval development. In our earliest collected larvae, parasitism by Bathyplectes spp. approached 30%. A low incidence of parasitism by O. incertus also was detected in these larvae. With rapidly declining numbers of host larvae available after first cutting, parasitism rates by B. curculionis and O. incertus increase greatly, with Oomyzus assuming greater importance as Bathyplectes declines. The greatest incidence of O. incertus parasitism occurred ~500 to 600 dd, but the proportion of the hosts that were parasitized peaked at ~750 to 900 dd. Insecticide sprays for potato leafhopper, Empoasca fabae (Harris), usually between 300 to 900 dd, could adversely effect B. curculionis and O. incertus.Second-generation alfalfa weevil larvae were found each year, but were most common during an unusually cool summer (1992), and in the southern half of the transect. Density of second-generation larvae peaked after mid-August (~1000 dd). Each year, peak parasitism by M. aethiopoides was observed during its first generation, around 300 dd, in overwintering alfalfa weevils. There may have been three generations of M. aethiopoides in Minnesota in 1992 and in 1993. In Minnesota, M. aethiopoides apparently overwinters as eggs, first-instar larvae, or advanced stage larvae.

Evaluating the establishment success of Microctonus aethiopoides (Hymenoptera: Braconidae), a parasitoid of the alfalfa weevil (Coleoptera: Curculionidae), across the northern Great Plains of North America

2018 ◽  
Vol 150 (2) ◽  
pp. 274-277 ◽  
Author(s):  
Tatyana A. Rand ◽  
Makenzie Pellissier ◽  
Randa Jabbour ◽  
Jonathan G. Lundgren ◽  
Debra K. Waters
Keyword(s):  
Biological Control ◽  
Great Plains ◽  
Biological Control Agent ◽  
Control Agent ◽  
Northern Great Plains ◽  
Alfalfa Weevil ◽  
Hypera Postica ◽  
Microctonus Aethiopoides

AbstractThe alfalfa weevil (Hypera postica (Gyllenhal); Coleoptera: Curculionidae), is a destructive pest of alfalfa (Medicago sativa Linnaeus; Fabaceae) worldwide. The biological control parasitoid, Microctonus aethiopoides Loan (Hymenoptera: Braconidae), was successfully introduced, and considered highly effective, in the eastern and mid-western United States of America. Redistribution efforts carried out throughout the 1980s reported initial establishment in the northern Great Plains, however follow-up studies to assess long-term persistence and efficacy are lacking. We resurveyed the counties in which M. aethiopoides had been initially recovered following redistribution in Montana (Flathead and Petroleum counties), Wyoming (Platte County), and South Dakota (Brookings County), to gauge whether this species has become permanently established and, if so, assess levels of parasitism in the field. We collected adult weevils from five fields in each county, and reared them in the laboratory to assess parasitism. Despite rearing more than 1000 weevils, no parasitoids were recovered from any of the locations sampled in our study, suggesting a widespread failure of M. aethiopoides to persist in the region. Thus, M. aethiopoides does not currently appear to be an important biological control agent of alfalfa weevil in the northern Great Plains. More intensive surveys will be required to assess the extent of the distributional limits of this species throughout the region.

scholarly journals Mutational analyses of fs(1)Ya, an essential, developmentally regulated, nuclear envelope protein in Drosophila.

Genetics ◽  
1995 ◽  
Vol 141 (4) ◽  
pp. 1473-1481 ◽  
Author(s):  
J Liu ◽  
K Song ◽  
M F Wolfner
Keyword(s):  
Cell Cycle ◽  
Embryonic Development ◽  
Nuclear Envelope ◽  
Envelope Protein ◽  
Chromatin Condensation ◽  
Cell Cycle Control ◽  
Nuclear Lamina ◽  
Mitotic Division ◽  
Developmentally Regulated ◽  
Egg Maturation

Abstract The fs(1)Ya protein (YA) is an essential, maternally encoded, nuclear lamina protein that is under both developmental and cell cycle control. A strong Ya mutation results in early arrest of embryos. To define the function of YA in the nuclear envelope during early embryonic development, we characterized the phenotypes of four Ya mutants alleles and determined their molecular lesions. Ya mutant embryos arrest with abnormal nuclear envelopes prior to the first mitotic division; a proportion of embryos from two leaky Ya mutants proceed beyond this but arrest after several abnormal divisions. Ya unfertilized eggs contain nuclei of different sizes and condensation states, apparently due to abnormal fusion of the meiotic products immediately after meiosis. Lamin is localized at the periphery of the uncondensed nuclei in these eggs. These results suggest that YA function is required during and after egg maturation to facilitate proper chromatin condensation, rather than to allow a lamin-containing nuclear envelope to form. Two leaky Ya alleles that partially complement have lesions at opposite ends of the YA protein, suggesting that the N- and C-termini are important for YA function and that YA might interact with itself either directly or indirectly.

EFFECTS OF CARBOFURAN ON ARTHROPOD POPULATIONS AND CROP YIELD IN HAYFIELDS

1972 ◽  
Vol 104 (9) ◽  
pp. 1433-1437 ◽  
Author(s):  
C. D. Dondale
Keyword(s):  
Crop Yield ◽  
Crude Protein ◽  
Alfalfa Weevil ◽  
Hypera Postica

AbstractCarbofuran was applied to three hayfields at a rate of 0.56 kg/ha in early June. This caused significant reductions of Thysanoptera, phytophagous Coleoptera larvae (including the alfalfa weevil, Hypera postica (Gyl.)), and Cicadellidae. It caused similar reductions in Araneida and parasitoids. The differences between treated and untreated plots were no longer significant by September. Carbofuran did not significantly affect the yield of air-dried hay or of crude protein.

DIFFERENTIAL ENCAPSULATION OF TWO BATHYPLECTES PARASITOIDS AMONG ALFALFA WEEVIL STRAINS, HYPERA POSTICA (GYLLENHAL)

1991 ◽  
Vol 123 (1) ◽  
pp. 197-203 ◽  
Author(s):  
Christopher M. Maund ◽  
T.H. Hsiao
Keyword(s):  
Biological Control ◽  
Control Strategy ◽  
Laboratory Studies ◽  
Alfalfa Weevil ◽  
Hypera Postica ◽  
Biological Differences

AbstractEncapsulation of Bathyplectes curculionis (Thomson) and B. anurus (Thomson) (Hymenoptera: Ichneumonidae) was investigated by dissecting parasitized larvae of three strains of the alfalfa weevil, Hypera postica (Gyllenhal) (Coleoptera: Curculionidae). In laboratory studies, there was no encapsulation of B. curculionis in the western strain of the weevil, a significant level of encapsulation in the eastern strain of the weevil, and nearly complete encapsulation in the Egyptian strain of the weevil. The rickettsia, Wolbachia postica Hsiao and Hsiao, found only in the western strain, was not involved in encapsulation. Variation in encapsulation was due to biological differences between weevil strains. Encapsulation rates among field populations of the western and Egyptian weevils were lower than in the laboratory. Encapsulation rates of weevil populations from zones in which western and Egyptian strains overlap in southern Utah, and between eastern and western strains in Colorado, were intermediate to rates of parental strains. These results imply that B. curculionis effectiveness against the western alfalfa weevil will decline with mixing of weevil strains. Bathyplectes anurus did not evoke encapsulation and was able to develop equally well in all three weevil strains. Our findings illustrate the importance of investigating the compatibility between alfalfa weevil strains and their parasitoids in devising a sound biological control strategy.

Structure of the chloroplast and its DNA in chloromonadophycean algae

1981 ◽  
Vol 49 (1) ◽  
pp. 401-409
Author(s):  
A.W. Coleman ◽  
P. Heywood
Keyword(s):  
Endoplasmic Reticulum ◽  
Cell Membrane ◽  
Nuclear Envelope ◽  
Chloroplast Dna ◽  
Single Layer ◽  
Longitudinal Axis ◽  
Chloroplast Envelope ◽  
Large Numbers ◽  
Gonyostomum Semen ◽  
Chloroplast Stroma

The arrangement and ultrastructure of chloroplasts is described for the Chloromonadophycean algae gonyostomum semen Diesing and Vacuolaria virescens Cienkowsky. The chloroplasts are present in large numbers and are discoid structures approximately 3–4 micrometer in length by 2–3 micrometer in width. In Gonyostomum semen the chloroplasts form a single layer immediately interior to the cell membrane; frequently their longitudinal axis parallels the longitudinal axis of the cell. The chloroplasts in Vacuolaria virescens are more than I layer deep and do not appear to be preferentially oriented. In both organisms, chloroplast bands usually consist of 3 apposed thylakoids, although fusion and interconnections between adjacent bands frequently occur. External to the girdle band (the outermost thylakoids) is the chloroplast envelope. This is bounded by endoplasmic reticulum but there is no immediately apparent continuity between this endoplasmic reticulum and the nuclear envelope. Electron-dense spheres in the chloroplast stroma are thought to be lipid food reserve. Ring-shaped electron-translucent regions in the chloroplast contain chloroplast DNA. The DNA is distributed along this ring in an uneven fashion and, when stained, resembles a string of beads. Each plastid has I ring, and the ring is unbroken in the intact plastid.

Demographic studies of Oomyzus incertus (Hymenoptera: Eulophidae), a larval parasitoid of Hypera postica (Coleoptera: Curculionidae), treated with four organophosphorous insecticides

2005 ◽  
Vol 137 (4) ◽  
pp. 488-491
Author(s):  
Qodrat Sabahi ◽  
Khalil Talebi
Keyword(s):  
Life Cycle ◽  
Medicago Sativa ◽  
Fourth Instar ◽  
Northern Iran ◽  
Alfalfa Weevil ◽  
Hypera Postica ◽  
Larval Parasitoid ◽  
Organophosphorous Insecticides

The alfalfa weevil, Hypera postica (Gyllenhal) (Coleoptera: Curculionidae), can severely damage the first cutting of alfalfa, Medicago sativa L. (Fabaceae), in much of Iran. The pest has been parasitized by several parasitoids including Oomyzus incertus (Ratzeburg) (Hymenoptera: Eulophidae), a gregarious larval endoparasitoid. This wasp can parasitize up to 30% of weevil larvae in alfalfa fields in northern Iran. It produces three to four generations per year, and the female prefers the fourth instar of the host for oviposition. Each female lays 2 to 22 eggs per host, which hatch within 47–60 h. The life cycle is completed in about 2 weeks, upon pupation inside the host. This species is predominantly present during the summer months in alfalfa fields (Streams and Fuester 1967).

Alfalfa Weevil, Hypera postica (Gyllenhal) (Coleoptera: Curculionidae)

2008 ◽  
pp. 110-110
Author(s):  
George Hangay ◽  
Severiano F. Gayubo ◽  
Marjorie A. Hoy ◽  
Marta Goula ◽  
Allen Sanborn ◽  
...  
Keyword(s):  
Alfalfa Weevil ◽  
Hypera Postica
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