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Experientia

, Volume 52, Issue 3, pp 273–276 | Cite as

Mixed life cycles in the transitional zone between voltinisms in the fall webworm,Hyphantria cunea

Research Articles

Abstract

The fall webworm,Hyphantria cunea Drury, was introduced from North America into Japan at half a century ago. At present, the populations north of 36° N are bivoltine and those south of 36° N are trivoltine. In the present study, the life cycle in the transitional zone between voltinisms was clarified in Tsukuba (36.1° N). When fourth instar larvae of the second generation were collected in the field and maintained in the laboratory, the incidence of pupal diapause increased when the sampling date was delayed from 16 August to 5 September. The fact that some developed without diapause inidcates the occurrence of a trivoltine life cycle in this locality, where a bivoltine life cycle is predominant. The critical photoperiod for diapause induction at 20 and 25°C was 14 h 13 min and 14 h 10 min, respectively. The photoperiodic response may explain the rapid increase in diapause incidence in late summer. In laboratory-reared diapause pupae, the time and period of chilling (5°C) greatly influenced the time required for adult emergence at the final incubation temperature of 25°C. However, diapause pupae chilled for a sufficiently long period developed to adulthood rapidly, irrespective of the conditions before chilling. Therefore, the difference in timing of entering diapause between pupae of the second and third generations would not result in their temporal reproductive isolation in the following spring. It is concluded that the mixed voltinism in Tsukuba is not a result of a mixture of genetically distinct bivoltine and trivoltine populations, but a result of the phenotypic plasticity in a genetically rather homogeneous population.

Key words

Dipause Hyphantria cunea photoperiodic response transitional zone voltinism 

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References

  1. 1.
    Tauber, M. J., Tauber, C. A., and Masaki, S., Seasonal Adaptations of Insects. Oxford University Press, New York 1986.Google Scholar
  2. 2.
    Masaki, S., Rev. Plant Protect. Res.8 (1975) 14.Google Scholar
  3. 3.
    Gomi, T., The formation of geographic variation in the life cycle characteristics and the mechanism that enforced the voltinism change in the fall webworm,Hyphantria cunea Drury (Lepidoptera: Arctiidae). Kobe Univ. Ph.D. Thesis 1992.Google Scholar
  4. 4.
    Danks, H. V., Insect dormancy: an ecological perspective. Biological Survey of Canada, Ottawa 1987.Google Scholar
  5. 5.
    Masaki, S., Umeya, K., Sekiguchi, Y., and Kawasaki, R., Appl. Entomol. Zool.3 (1968) 55.Google Scholar
  6. 6.
    Gomi, T., and Takeda, M., Appl. Entomol. Zool.25 (1990) 483.Google Scholar
  7. 7.
    Gomi, T., and Takeda, M., Appl. Entomol. Zool.26 (1991) 357.Google Scholar
  8. 8.
    Morris, C. M., and Takeda, S., Appl. Entomol. Zool.28 (1993) 256.Google Scholar
  9. 9.
    Ando, Y., Bull. Fac. Agric. Hirosaki Univ.30 (1978) 131.Google Scholar
  10. 10.
    Masaki, S., in: Adaptation and Speciation in the Fall Webworm, p. 31. Ed. T. Hidaka. Kodansha, Tokyo 1977.Google Scholar
  11. 11.
    Takeda, M., and Masaki, S., Entomologia exp. appl.25 (1979) 386.Google Scholar
  12. 12.
    Schmidt, F. H., Can. Ent.109 (1977) 1469.Google Scholar
  13. 13.
    Collier, R. H., and Finch, S., Entomologia exp. appl.34 (1983) 186.Google Scholar
  14. 14.
    Morris, R. F., and Fulton, W. C., Mem. ent. Soc. Can.70 (1970) 1.Google Scholar
  15. 15.
    Lees, A. D., The physiology of diapause in arthropods. Cambridge monographs in experimental biology, No. 4. Cambridge University Press 1955.Google Scholar
  16. 16.
    Masaki, S., Evolution26 (1972) 587.Google Scholar
  17. 17.
    Kidokoro, T., and Masaki, S., Jap. J. Ecol.28 (1978) 291.Google Scholar
  18. 18.
    Taylor, F., Theor. popul. Biol.18 (1980) 125.PubMedGoogle Scholar

Copyright information

© Birkhäuser Verlag 1996

Authors and Affiliations

  • T. Gomi
    • 1
  1. 1.Graduate School of Science and TechnologyKobe UniversityNada, KobeJapan

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