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Bean Weevil (bean + weevil)
Selected AbstractsThe specialist seed predator Bruchidius dorsalis (Coleoptera: Bruchidae) plays a crucial role in the seed germination of its host plant, Gleditsia japonica (Leguminosae)FUNCTIONAL ECOLOGY, Issue 2 2002K. Takakura Summary 1,This paper describes the germination mechanism of hard seeds of a species of honey locust, Gleditsia japonica, which can germinate only when externally damaged, in relation to four germinating factors: feeding damage by two specialist seed predators, a bean weevil (Bruchidius dorsalis) and a cydid bug (Adrisa magna); feeding damage by a generalist seed predator, a wild mouse (Apodemus speciosus); and physical damage. 2,In laboratory experiments, both the bean weevil and physical damage facilitated germination, while damage by the cydid bug and wild mouse did not. 3,In contrast to laboratory findings, field censuses of G. japonica seed survival revealed that more than 99% were damaged either by B. dorsalis or A. magna. Therefore, less than 0·5% of the seeds remained intact, preventing formation of a seed bank. 4,In addition, all germinating seeds found in the field contained B. dorsalis larvae. 5,These results strongly suggest that damage by B. dorsalis is a prerequisite for G. japonica germination, in contrast to the conventional view that physical disturbance, possibly flooding, is the primary germinating factor for hard seeds. [source] Resistance of stored bean varieties to Acanthoscelides obtectus (Coleoptera: Bruchidae)INSECT SCIENCE, Issue 4 2008Edson L.L. Baldin Abstract During bean seed storage, yield can be lost due to infestations of Acanthoscelides obtectus Say, the bean weevil. The use of resistant varieties has shown promising results in fighting these insects, reducing infestation levels and eliminating chemical residues from the beans. The expression of resistance to A. obtectus in bean varieties is frequently attributed to the presence of phytohemagglutinins, protease inhibitors and alpha-amylase, and especially to variants of the protein arcelin, which reduce the larval viability of these insects. To evaluate the effect of bean seed storage time on the resistance expression of bean varieties to A. obtectus, tests with seeds of three ages (freshly-harvested, 4-month-old, and 8-month-old) were conducted in the laboratory, using four commercial varieties: Carioca Pitoco, Ipa 6, Porrillo 70, ônix; four improved varieties containing arcelin protein: Arc.1, Arc.2, Arc. 3, Arc.4; and three wild varieties also containing arcelin protein: Arc.1S, Arc.3S, and Arc. 5S. The Arc.5S, Arc.1S, and Arc.2 varieties expressed high antibiosis levels against the weevil; Arc.1 and Arcs expressed the same mechanism, but at lower levels. The occurrence of oviposition non-preference was also observed in Arc.5S and Arc.1S. The Arc.3 and Arc. 4 varieties expressed low feeding non-preference levels against A. obtectus. The expression of resistance in arcelin-bearing, wild or improved varieties was affected during the storage of seeds, and was high under some parameters but low in others. The results showed that addition of chemical resistance factors such as protein arcelin via genetic breeding may be beneficial in improving the performance of bean crops. [source] Development of an interspecific Vigna linkage map between Vigna umbellata (Thunb.) Ohwi & Ohashi and V. nakashimae (Ohwi) Ohwi & Ohashi and its use in analysis of bruchid resistance and comparative genomicsPLANT BREEDING, Issue 1 2006P. Somta Abstract To facilitate transfer of bruchid resistance to azuki bean (Vigna angularis) from its relatives an interspecific mapping population was made between rice bean, V. umbellata, and the related wild species V. nakashimae. The V. umbellata parent is completely resistant and V. nakashimae is completely susceptible to the bruchid beetle pests, azuki bean weevil (Callosobruchus chinensis) and cowpea weevil (C. maculatus). There is very low cross compatibility between V. umbellata and azuki bean. Therefore, V. nakashimae, that crosses with both V. umbellata and V. angularis without the need for embryo rescue, is used as a bridging species. A genetic linkage map was constructed based on an interspecific F2 mapping population between V. umbellata and V. nakashimae consisting of 74 plants. A total of 175 DNA marker loci (74 RFLPs and 101 SSRs) were mapped on to 11 linkage groups spanning a total length of 652 cM. Segregation distortion was observed but only three markers were not linked to any linkage group due to severe segregation distortion. This interspecific genome map was compared with the genome map of azuki bean. Of 121 common markers on the two maps, 114 (94.2%) were located on the same linkage groups in both maps. The marker order was highly conserved between the two genome maps. Fifty F2 plants that produced sufficient seeds were used for quantitative trait locus (QTL) analysis and locating gene(s) for C. chinensis and C. maculatus resistance in V. umbellata. The resistance reaction of these F2 plants differed between C. chinensis and C. maculatus. Both resistances were quantitatively inherited with no F2 plants completely susceptible to C. chinensis or C. maculatus. One putative QTL for resistance to each of these bruchid species was located on different linkage groups. Other putative QTLs associated with resistance to both C. chinensis and C. maculatus were localized on the same linkage group 1. Linked markers associated with the bruchid-resistant QTL will facilitate their transfer to azuki bean breeding lines. [source] Structure and enzyme properties of Zabrotes subfasciatus ,-amylaseARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY (ELECTRONIC), Issue 2 2006Patrícia B. Pelegrini Abstract Digestive ,-amylases play an essential role in insect carbohydrate metabolism. These enzymes belong to an endo-type group. They catalyse starch hydrolysis, and are involved in energy production. Larvae of Zabrotes subfasciatus, the Mexican bean weevil, are able to infest stored common beans Phaseolus vulgaris, causing severe crop losses in Latin America and Africa. Their ,-amylase (ZSA) is a well-studied but not completely understood enzyme, having specific characteristics when compared to other insect ,-amylases. This report provides more knowledge about its chemical nature, including a description of its optimum pH (6.0 to 7.0) and temperature (20,30°C). Furthermore, ion effects on ZSA activity were also determined, showing that three divalent ions (Mn2+, Ca2+, and Ba2+) were able to enhance starch hydrolysis. Fe2+ appeared to decrease ,-amylase activity by half. ZSA kinetic parameters were also determined and compared to other insect ,-amylases. A three-dimensional model is proposed in order to indicate probable residues involved in catalysis (Asp204, Glu240, and Asp305) as well other important residues related to starch binding (His118, Ala206, Lys207, and His304). Arch. Insect Biochem. Physiol. 61:77,86, 2006. © 2006 Wiley-Liss, Inc. [source] | ||||||||||