Researches on Population Ecology

, Volume 30, Issue 2, pp 297–313

Life table studies of the walnut leaf beetle,Gastrolina depressa (Coleoptera: Chrysomelidae), with special attention to aggregation

  • Kwang-Shing Chang
  • Naotake Morimoto
Article

DOI: 10.1007/BF02513251

Cite this article as:
Chang, K. & Morimoto, N. Res Popul Ecol (1988) 30: 297. doi:10.1007/BF02513251
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Summary

In order to make clear the relationship between the mortality processes and aggregation on the walnut leaf beetle,Gastrolina depressa, life tables of individual colonies were developed and the major mortality factor and the mode of its action were investigated. Furthermore, the influences of the larval colony size on the survival rate and the developmental period were also investigated in the laboratory.

In the laboratory, when the larvae were reared on suitable (soft) host plants, the larger the group size, the faster the development. When the larvae were reared on unsuitable (hard) host plants, the larger the group size, the higher the survival rate. In the field, one of the major mortality factors of the egg stage was physiological death. However, there was no particular relation between the egg mass size and hatchability. On the other hand, another mortality factor of eggs, predation byA. hexaspilota, tended to act more on the larger sized egg masses. The mortality of the 1st instar larvae decreased with the increase of colony size. During the larval stages, the major mortality factor was predation byA. hexaspilota andP. japonica. Both predators tended to attack the colony in an all-or-none manner. The number of male adults was much less than the number of females in the Ina populations.

Copyright information

© Society of Population Ecology 1988

Authors and Affiliations

  • Kwang-Shing Chang
    • 1
  • Naotake Morimoto
    • 2
  1. 1.Laboratory of Applied Entomology, Faculty of AgricultureOkayama UniversityOkayama cityJapan
  2. 2.Laboratory of Applied Entomology, Faculty of AgricultureShinshu UniversityNaganoJapan