Abstract
The effects of egg clutch size on development and survivorship of the larger grain borer, Prostephanus truncatus (Horn) (Col.: Bostrichidae) on maize were measured in the laboratory using single grains of the white maize variety, TZSR-W, at 30 ± 2°C and 70 ± 5% RH. Varying numbers of P. truncatus eggs (1, 2, 4, 8, or 16) were introduced into a hole drilled into a single maize grain. Destructive sampling was used at regular intervals to obtain data on immature developmental parameters, the location of immatures within the grain and the weight and sex of any emerged adults. First instars fed mainly on the floury endosperm tissue whereas the second and third instars preferred the germ tissue. Mortality due to competition was highest in first instars. At high initial densities (> 4 per kernel), some P. truncatus larvae reduced competition by moving out of the grain. A maximum of 6 adults emerged from a single grain. The mean number of adults that emerged per grain for initial egg densities of 8 and 16 were 3.3 and 3.5, respectively. Prostephanus truncatus adult weight at emergence was not significantly influenced by initial egg density except in the case of clutch size 16. The sex ratio of emerged adults was also unaffected by competition, and was always 1:1. Complete developmental period within grains ranged between 28 and 32 days.
Résumé
Les effets de la taille de la fournée d’oeufs déposés par le grand capucin, Prostephanus truncatus (Horn) (Coleoptera: Bostrichidae), sur son développement et sa survie, ont été étudiés au laboratoire sur les graines isolées du maïs blanc, variété TZSR-W, à une température de 30 ± 2°C et une humidité relative de 70 ± 5%. Un nombre différent d’oeufs (1,2, 4,8 ou 16) de P. truncatus a été introduit dans un trou foré dans chaque graine de maïs. Une méthode destructive a été utilisée à des intervalles réguliers pour recueillir les données sur les paramètres de développement larvaire, la localisation des stades immatures à l’intérieur de la graine ainsi que le poids et le sexe des adultes émergés. Les premiers stades larvaires se nourrissaient principalement de l’endosperme tandis que les second et troisième stades larvaires préféraient se nourrir sur le germe. La mortalité due à la compétition nutritionnelle était très élevée chez les larves du premier stade. A des densités initiales élevées (> 4 individus par grain), certaines larves de P. truncatus évitaient cette compétition en sortant de la graine. Un maximum de 6 adultes a émergé d’une seule graine. Avec des densités initiales de 8 et 16 oeufs par graine, la moyenne d’adultes émergés étaient respectivement de 3,3 et 3,5. Le poids moyen des adultes à l’émergence n’était pas significativement influencé par la densité initiale d’oeufs, sauf dans le cas de 16 oeufs par graine. Le rapport de mâles et femelles adultes n’était pas affecté par la compétition et il est resté tout le temps de 1:1. Le développement complet de l’insecte à l’intérieur des graines se rangeait entre 28 et 32 jours.
Similar content being viewed by others
References
Abacus Concepts Inc. (1992) StatView Statistical Package, Abacus Concepts Inc., Berkeley, CA, USA.
Anderson F. S. (1961) Effect of density on animal sex ratio. Oikos 12, 1–16.
AOAC (1984) Official methods of analysis. Association of Official Analytical Chemists. 13th edition. Washington DC, USA.
Ashby K. R. (1961) The population dynamics of Cryptolestes ferrugineus (Stephens) in flour and on Manitoba wheat. Bull. Entomol. Res. 52, 363–379.
Crombie A. C. (1944) On intraspecific and interspecific competition in larvae of graminivorous insects. J. Exp. Biol. 20, 135–151.
Dunstan W. R. and Magazini I. A. (1981) Outbreaks and new records. Tanzania. The larger grain borer on stored products. PAO Plant Prot. Bull. 29, 80–81.
Godfray H. C. J. (1986) Clutch size in a leaf mining fly (Pegomya nigritarsis: Anthomyiidae). Ecol. Entomol. 11, 75–81.
Hodges R. J. (1982) A review of the biology and control of the greater grain borer Prostephanus truncatus (Horn) (Col.: Bostrichidae). Trop. Stored Prod. Info. 43, 3–9.
Hodges R. J. (1986) The biology and control of Prostephanus truncatus (Horn) (Coleoptera: Bostrichidae). A destructive storage pest with an increasing range. J. stored Prod. Res. 22, 1–14.
Hodges R. J., Cork A. and Hall D. R. (1984) Aggregation pheromones for monitoring the greater grain borer Prostephanus truncatus. British Crop Prot. Conf.— Pests and Diseases. Brighton, Nov. 1984, pp. 255–260.
Hodges R. J., Dunstan W. R., Magazini I. and Golob P. (1983) An outbreak of Prostephanus truncatus (Horn) (Coleoptera: Bostrichidae) in East Africa. Prot. Ecol. 5, 183–194.
Klomp H. (1964) Intraspecific competition and the regulation of insects numbers. Anna. Rev. Entomol. 9, 17–40.
Li L. (1988) Behavioural ecology and life history evolution in the larger grain borer Prostephanus truncatus (Horn). PhD thesis, University of Reading, UK. 229 pp.
Markham R. H., Meikle W. G., Adda C., Djomamou B. and Borgemeister C. (1996) Progress towards integration of control strategies in West Africa, pp. 81–100. In Proc. East and Centr. Africa Storage Pest Management Workshop Naivasha, Kenya. April 14–19, 1996 (Edited by G. Hill and G. Farrell). CAB Wallingford, UK.
Markham R. H., Wright V. F. and Rios Ibarra R. M. (1991) A selective review of research on Prostephanus truncatus (Col.: Bostrichidae) with an annotated and updated bibliography. Ceiba 32, 1–90.
Shires S. W. (1980) Influence of temperature and humidity on survival, development period and ad ult sex ratio in Prostephanus truncatus (Horn) (Coleoptera: Bostrichidae). J. Stored Prod. Res. 15, 510.
Shires S. W. and McCarthy S. (1976) A character for sexing live adults of Prostephanus truncatus (Horn) (Coleoptera: Bostrichidae). J. stored Prod. Res. 12, 273–275.
Snyman A. (1949) The influence of population densities on the development and oviposition of Plodia interpunctella Hübn.. J. Entomol. Soc. S. Africa 12, 137–171.
Subramanyam Bh., Cutkomp L. K. and Darveaux B. A. (1985) A new character for identifying larval instars of Prostephanus truncatus (Horn) (Coleoptera: Bostrichidae). J. stored Prod. Res. 21, 101–104.
Ullyett G. C. and Merwe J. S. (1947) Some factors influencing population growth of Ephestiakuehniella Zell. j. Entomol. Soc. S. Africa 10, 46–63.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Vowotor, K.A., Meikle, W.G., Ayertey, J.N. et al. Intraspecific Competition in Larvae of the Larger Grain Borer, Prostephanus truncatus (Horn) within Maize Grains. Int J Trop Insect Sci 18, 171–175 (1998). https://doi.org/10.1017/S1742758400023365
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1017/S1742758400023365