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Feeding by Adults of Prostephanus truncatus (Horn) (Coleoptera: Bostrichidae) on Shelled Maize: Influence of Damaged Grain, Adult Crowding and Grain Density

Published online by Cambridge University Press:  19 September 2011

Bh. Subramanyam
Affiliation:
Department of Entomology, University of Minnesota, St. Paul, Minnesota 55108, USA
P. K. Harein
Affiliation:
Department of Entomology, University of Minnesota, St. Paul, Minnesota 55108, USA
L. K. Cutkomp
Affiliation:
Department of Entomology, University of Minnesota, St. Paul, Minnesota 55108, USA
C. Pegors
Affiliation:
Department of Entomology, University of Minnesota, St. Paul, Minnesota 55108, USA
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Abstract

In the laboratory, adults of Prostephanus truncatus (Horn) preferred artificially or naturally (insect) damaged maize kernels to sound kernels when adults were tested individually or in groups. Survival of P. truncatus was similar when 1, 10, 40 or 80 adults were fed 100 g of shelled maize for 20 days; but more kernels were damaged at the highest adult density in comparison to the other densities of adults. Single P. truncatus adults on average damaged 9 maize kernels, but 10, 40, and 80 adults damaged approximately 15, 21 and 45 kernels, respectively, indicating that adults confined their feeding to only specific kernels. Survival of adults and number of kernels damaged were significantly affected when different quantities of shelled maize (25–500 g) were infested with 25 adults of P. truncatus. Adult surv at 25, 50, 100, and 200 g of maize/0.95–1 jar was similar (70.7–76.0%), but the number of kernels dama increased significantly from approximately 15 at 25 g to 61 at 200 g. These results suggested that shelled maize grain compaction, which is influenced by the quantity of grain, may affect survival of and damage by adults of P. truncatus. Adults of P. truncatus successfully infested 25 g of shelled maize and damaged about 15 kernels, indicating that adults could temporarily survive on such small quantities of grain spilled in and around storages before infesting stored-maize.

Résumé

Les adultes de Prostephanus truncatus (Horn) ont nettement preferé les grains de maïs endommagés aux grains entiers, quand testés individuellement ou en groupes. La survie des adultes P. truncatus s'est averée similaire quand 1, 10, 40 ou 80 adultes ont infesté 100 g de maïs pour une durée de 20 jours. Un nombre élevé de grains a subi des degats aux densités les plus elevées comparé aux au densités. En moyenne, un seul adult de P. truncatus a endommagé 9 grains de maïs, maïs 10, 40 et 80 adultes ont infesté approximativement 15, 21 et 45 grains respectivement. Ceçi nous indique que l'attaque par les adultes a été reduite à des grains spécifiques. La survie des adultes et le nombre de gr; endommagés ont été significativement affectés aux densités de grains suivantes: 25, 50, 100, 200, 300 et 500 g de maïs/0.951 jare, infestés par 25 P. truncatus adultes, pour une durée de 20 jours. La survie des adultes aux densités de 25, 50, 100 et 200 g de grain semblait similaire (70.7–76.0%), maïs s'est averée inferieure à celle aux densités de 300 et 500 g de grain (50.7–58.7%). Le nombre de grains endommagés s'est significativement élevé de 15.3 a 61.3 aux densités respectives de 25 et 200 g. Le nombre de grains endommagés n'a pas été significativement different aux densités de 200, 300 et 500 g de grain. Ces resultats suggèrent que la quantité de grain crée une compaction qui pourrait affecter la survie de P. truncatus. Les adultes ont succedé à infester 25 g de mais et à endommager 15 grains, indiquant que les adu peuvent survivre sur de petites quantités de grains éparpillées aux alentours des lieux de stockage av d'infester le maïs stocké.

Type
Research Articles
Copyright
Copyright © ICIPE 1988

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References

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