DISPLACEMENT OF BATHYPLECTES CURCULIONIS (THOMS.) (HYMENOPTERA: ICHNEUMONIDAE) BY B. ANURUS (THOMS.) IN EASTERN ONTARIO POPULATIONS OF THE ALFALFA WEEVIL, HYPERA POSTICA (GYLL.) (COLEOPTERA: CURCULIONIDAE)

1990 ◽  
Vol 122 (4) ◽  
pp. 641-645 ◽  
Author(s):  
D.G. Harcourt
Keyword(s):  
Aggressive Behaviour ◽  
Reproductive Capacity ◽  
Alfalfa Weevil ◽  
Hypera Postica ◽  
Parasitoid Community ◽  
Larval Parasitoid ◽  
Direct Competition ◽  
Eastern Ontario ◽  
Better Than

AbstractBathyplectes anurus (Thoms.) has displaced B. curculionis (Thorns.) as the main larval parasitoid in populations of the alfalfa weevil, Hypera postica (Gyll.), in eastern Ontario. Following its belated spread to the Bay of Quinte dairy belt, it used a combination of r and K strategies to assert its superiority: a greater reproductive capacity, more rapid search and handling, and more aggressive behaviour. Also, it is not subject to encapsulation by the host and reduces direct competition with the entomopafhogenic fungus Zoophthora phytonomi (Arthur) by laying its eggs in older hosts that have a greater probability of escaping death from disease. Taken together, these factors have enabled it to perform better than B. curculionis and to displace it in the host–parasitoid community. Moreover, it may have the potential to stabilize weevil populations during years when the fungus is enzootic.

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).

THE ANALYSIS OF INTRAGENERATION CHANGE IN EASTERN ONTARIO POPULATIONS OF THE ALFALFA WEEVIL, HYPERA POSTICA (COLEOPTERA: CURCULIONIDAE)

1977 ◽  
Vol 109 (12) ◽  
pp. 1521-1534 ◽  
Author(s):  
D. G. Harcourt ◽  
J. C. Guppy ◽  
M. R. Binns
Keyword(s):  
Population Decline ◽  
Mortality Data ◽  
Mortality Factors ◽  
Independent Manner ◽  
Alfalfa Weevil ◽  
Hypera Postica ◽  
Key Factor ◽  
Components Analysis ◽  
Eastern Ontario ◽  
Factor Governing

AbstractFifteen life tables were compiled from population and mortality data collected in the Quinte area of eastern Ontario during the 5-year period, 1972–76, that spanned the rise and fall of an outbreak of the alfalfa weevil, Hypera postica (Gyll.).Components analysis of the data showed that a disease of the feeding larvae caused by Entomophthora phytonomi Arthur, a fungus new to the insect in North America, was the principal determinant of intrageneration survival. Multivariate analysis of the separate mortalities, expressed as k-values, confirmed that this agent was the key factor governing population trends of the weevil and was mainly responsible for its population decline.Examination of the properties of the various mortality factors showed that E. phytonomi was density dependent but overcompensating. Other agents, including the parasitoids Bathyplectes curculionis (Thom.) and Tetrastichus incertus (Ratz.) acted in a density independent manner and contributed little to population trend.

ADAPTIVE STRATEGIES OF LARVAL PARASITOIDS OF THE ALFALFA WEEVIL (COLEOPTERA: CURCULIONIDAE)

1977 ◽  
Vol 109 (5) ◽  
pp. 641-648 ◽  
Author(s):  
Robert V. Dowell ◽  
David J. Horn
Keyword(s):  
Random Search ◽  
Adaptive Strategies ◽  
Reproductive Capacity ◽  
Alfalfa Weevil ◽  
Hypera Postica ◽  
Larval Parasitoids

AbstractThree species of Hymenoptera comprise the guild of parasitoids utilizing alfalfa weevil, Hypera postica, larvae in Ohio. Where all three coexist, there has been a yearly increase in parasitization by Bathyplectes anurus and concomitant decreases in Bathyplectes curculionis and Tetrastichus incertus. We conclude that B. anurus dominance is due to its precise synchronization with peak host numbers, its high reproductive capacity, competitive superiority, and rapid search and handling. Domination of ephemeral hosts by such a parasitoid is in agreement with the general conclusions of Force, and Ehler and van den Bosch. B. curculionis and T. incertus compensate for imperfect synchrony with multivoltism and vagility (both spp.), aggregation and rapid search (B. curculionis), or random search and gregarious development (T. incertus).

Establishment of Bathyplectes anurus (Hymenoptera: Ichneumonidae), a larval parasitoid of the alfalfa weevil, Hypera postica (Coleoptera: Curculionidae) in Japan

2005 ◽  
Vol 34 (2) ◽  
pp. 144-151 ◽  
Author(s):  
Megumi Shoubu ◽  
Masami Okumura ◽  
Akinori Shiraishi ◽  
Hidenori Kimura ◽  
Masami Takagi ◽  
...  
Keyword(s):  
Alfalfa Weevil ◽  
Hypera Postica ◽  
Larval Parasitoid

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.

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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