[ Objective] Coffee bean weevil （Araecerusfasciculatus De Geer） is a worldwide important pest in storehouse, which distributes in tropical and subtropi- cal region, having overlapping ecological zone with the import...[ Objective] Coffee bean weevil （Araecerusfasciculatus De Geer） is a worldwide important pest in storehouse, which distributes in tropical and subtropi- cal region, having overlapping ecological zone with the important biofuel plant Jatropha curcas L.. The paper was to investigate the damage of coffee bean weevil on J. curcas. [Method] Taking planting area in Luodian County of Guizhou Province as the investigation point, the forest stand of J. curcas in field and the indoor stored fruits were investigated, and the occurrence condition and damage consequence of the pest were grasped. Furthermore, the taxonomic status of the pest was also confirmed. [ Result] Coffee bean weevil had common distribution in planting area of J. curcas in Luodian, which was found to cause damage beth in field and indoor condition. The adults of coffee bean weevil fed on fungi with little direct damage on the fruit of J. curcas. However, the adults of the post laid their eggs in- side the peel of fruit, and the larvae hatched and fed inside the peel, resulting in the collapse of the peels, thus causing direct damage on the fruit. In addition, coffee bean weevil might have series of potential damages including direct feeding on seeds, spreading diseases, and posing damage on other economic crops in pro- duction area, etc.. [ Conclusion] J. curcas was an important new host for coffee bean weevil. The pest had certain damage on the plant, which also had potential damage on plant products and other economic crops. The research and control efforts on coffee bean weevil should be strengthened.展开更多
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 infestat...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-monthold） were conducted in the laboratory, using four commercial varieties： Carioca Pitoco, Ipa 6, Porrillo 70, Onix; four improved varieties containing arcelin protein： Arc. 1, Arc.2, Arc. 3, Arc.4; and three wild varieties also containing arcelin protein： Arc.lS, Arc.3S, and Arc. 5S. The Arc.5S, Arc.lS, and Arc.2 varieties expressed high antibiosis levels against the weevil; Arc.1 and Arc3S 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.展开更多
The effects of competition on populations of the bean weevil Zabrotes sub- fasciatus were analyzed during 41 generations under different competition levels. Three competition environments were established by maintaini...The effects of competition on populations of the bean weevil Zabrotes sub- fasciatus were analyzed during 41 generations under different competition levels. Three competition environments were established by maintaining the number of couples （6） and varying the amount of available host seeds： HC, high （limited availability of host： 1.35 g）; IC, intermediate （intermediate availability of host： 6 g）; and LC, low competition （abun- dance of host： 36 g）. It was found that the distribution of the eggs laid on grains was different among treatments： in LC, for example, although females showed high fecundity （35.4 ± 5.6 eggs/female） the number of eggs laid on each grain was small （1.2 ± 0.4 eggs on each seed）, thus avoiding larval competition of their offspring; whereas in HC treatment, females showed low fecundity （27.04 ± 4.5 eggs/female） but laid many eggs on each grain （15.03 ± 4.3 eggs）. There were no changes in the ability to respond to different amounts of host via oviposition behavior （egg distribution） during 41 generations. How- ever, HC females had more offspring than LC females under HC conditions. This suggests that HC insects evolved toward higher fitness in crowded conditions. In addition, after inverting the competition level, insects behaved independently of the treatment conditions they experienced through generations, thus showing that oviposition behavior is flexible. Taken together, our results show that Z. subfasciatus presents a broad range of behavioral and physiological responses which allows for quick and reversible adjustments to sudden changes in the amount of resources.展开更多
基金Supported by Guizhou Provincial Key Research Project(QKH NY(2009)3065)~~
文摘[ Objective] Coffee bean weevil （Araecerusfasciculatus De Geer） is a worldwide important pest in storehouse, which distributes in tropical and subtropi- cal region, having overlapping ecological zone with the important biofuel plant Jatropha curcas L.. The paper was to investigate the damage of coffee bean weevil on J. curcas. [Method] Taking planting area in Luodian County of Guizhou Province as the investigation point, the forest stand of J. curcas in field and the indoor stored fruits were investigated, and the occurrence condition and damage consequence of the pest were grasped. Furthermore, the taxonomic status of the pest was also confirmed. [ Result] Coffee bean weevil had common distribution in planting area of J. curcas in Luodian, which was found to cause damage beth in field and indoor condition. The adults of coffee bean weevil fed on fungi with little direct damage on the fruit of J. curcas. However, the adults of the post laid their eggs in- side the peel of fruit, and the larvae hatched and fed inside the peel, resulting in the collapse of the peels, thus causing direct damage on the fruit. In addition, coffee bean weevil might have series of potential damages including direct feeding on seeds, spreading diseases, and posing damage on other economic crops in pro- duction area, etc.. [ Conclusion] J. curcas was an important new host for coffee bean weevil. The pest had certain damage on the plant, which also had potential damage on plant products and other economic crops. The research and control efforts on coffee bean weevil should be strengthened.
文摘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-monthold） were conducted in the laboratory, using four commercial varieties： Carioca Pitoco, Ipa 6, Porrillo 70, Onix; four improved varieties containing arcelin protein： Arc. 1, Arc.2, Arc. 3, Arc.4; and three wild varieties also containing arcelin protein： Arc.lS, Arc.3S, and Arc. 5S. The Arc.5S, Arc.lS, and Arc.2 varieties expressed high antibiosis levels against the weevil; Arc.1 and Arc3S 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.
文摘The effects of competition on populations of the bean weevil Zabrotes sub- fasciatus were analyzed during 41 generations under different competition levels. Three competition environments were established by maintaining the number of couples （6） and varying the amount of available host seeds： HC, high （limited availability of host： 1.35 g）; IC, intermediate （intermediate availability of host： 6 g）; and LC, low competition （abun- dance of host： 36 g）. It was found that the distribution of the eggs laid on grains was different among treatments： in LC, for example, although females showed high fecundity （35.4 ± 5.6 eggs/female） the number of eggs laid on each grain was small （1.2 ± 0.4 eggs on each seed）, thus avoiding larval competition of their offspring; whereas in HC treatment, females showed low fecundity （27.04 ± 4.5 eggs/female） but laid many eggs on each grain （15.03 ± 4.3 eggs）. There were no changes in the ability to respond to different amounts of host via oviposition behavior （egg distribution） during 41 generations. How- ever, HC females had more offspring than LC females under HC conditions. This suggests that HC insects evolved toward higher fitness in crowded conditions. In addition, after inverting the competition level, insects behaved independently of the treatment conditions they experienced through generations, thus showing that oviposition behavior is flexible. Taken together, our results show that Z. subfasciatus presents a broad range of behavioral and physiological responses which allows for quick and reversible adjustments to sudden changes in the amount of resources.
