scholarly journals Invasion, dissemination, increase of density and seasonal trend of occurrence of the rice water weevil, Lissorhoptrus oryzophilus KUSCHEL in Fukuoka Prefecture.

1985 ◽  
Vol 31 ◽  
pp. 106-109
Author(s):  
Masahiro YAMANAKA ◽  
Nozomu FUJIYOSHI ◽  
Keisuke YOSHIDA
Insects ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 278
Author(s):  
Pengcheng Wang ◽  
Fangyuan Yang ◽  
Zhuo Ma ◽  
Runzhi Zhang

Rice water weevil (RWW) is divided into two types of population, triploid parthenogenesis and diploid bisexual reproduction. In this study, we explored the meiosis of triploid parthenogenesis RWW (Shangzhuang Town, Haidian District, Beijing, China) by marking the chromosomes and microtubules of parthenogenetic RWW oocytes via immunostaining. The immunostaining results show that there is a canonical meiotic spindle formed in the triploid parthenogenetic RWW oocytes, but chromosomes segregate at only one pole, which means that there is a chromosomal unipolar division during the oogenesis of the parthenogenetic RWW. Furthermore, we cloned the conserved sequences of parthenogenetic RWW REC8 and Tws, and designed primers based on the parthenogenetic RWW sequence to detect expression patterns by quantitative PCR (Q-PCR). Q-PCR results indicate that the expression of REC8 and Tws in ovarian tissue of bisexual Drosophila melanogaster is 0.98 and 10,000.00 times parthenogenetic RWW, respectively (p < 0.01). The results show that Tws had low expression in parthenogenetic RWW ovarian tissue, and REC8 was expressed normally. Our study suggests that the chromosomal unipolar division and deletion of Tws may cause parthenogenesis in RWW.


2010 ◽  
Vol 42 (2) ◽  
pp. 81 ◽  
Author(s):  
Daniela Lupi ◽  
Mario Colombo ◽  
Maria Luisa Giudici ◽  
Bruno Villa ◽  
Cesare Cenghialta ◽  
...  

A five year study has been made to establish the spread of the rice water weevil <em>Lissorhoptrus oryzophilus</em> (Coleoptera: Erirhinidae) in Northern Italy. Data obtained with GPS from 2005 throughout 2009 were first georeferenced with SW ArcGis&reg; 9.2, then overlapped and compared to the map of the European environmental landscape based on the interpretation of satellite images (CORINE Land Cover map) and to the hydrographic chart CT10 (Technical Regional map 10000). The analysis of the radial rate of spread per year indicates a deceleration in the expansion from 10.864 &plusmn; 6.801 km/year in 2005 to 5.318 &plusmn; 1.401 km/year in 2009. In five years the weevil has expanded its distribution in nearly all rice paddies in Lombardy and Piedmont, over an area of about 200,000 ha, which correspond to 86% of the total Italian rice area. Its expansion is thought to follow a type of stratified dispersal, due both to insect adult active dispersal and to accidental movements caused by human transportation.


1966 ◽  
Vol 98 (10) ◽  
pp. 1118-1119 ◽  
Author(s):  
L. F. Wilson ◽  
C. D. Waddell ◽  
I. Millers

The median depression on the last abdominal sternite is a useful character for distinguishing, in the field, the male from the female adult of all North American Hylobius species.Everett and Newsom (1964) used a midline depression or sulcus on the abdominal sternites to separate the sexes of the rice water weevil, Lissorhoptrus oryzophilus (Kushel), and other weevils that are not closely related to species of Hylobius in North America. The male of Hylobius abietis L., a European relative, is distinguished from the female by a saucerlilte depression on the last sternite (Anonymous 1952). Millers et al. (1963) state that the first and second visible abdominal sterna of the male H. rhizophagus Millers are concave, and the fifth has a slight median depression; the female sterna are convex.


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