, Volume 75, Issue 3, pp 472–480

The significance of carnivory for the fitness of Drosera in its natural habitat

1. The reactions of Drosera intermedia and D. rotundifolia to supplementary feeding
  • Martin Thum
Original Papers

DOI: 10.1007/BF00376954

Cite this article as:
Thum, M. Oecologia (1988) 75: 472. doi:10.1007/BF00376954


The effects on Drosera intermedia and D. rotundifolia of supplementary feeding with Drosophila melanogaster were studied in plants growing in their natural habitat. The artificial food supply was within the natural range of prey quantity. In both species supplementary feeding led to significantly higher dry weights of summer and winter plant, more leaves, more flowers, more seeds, and a larger trapping area. The dry weight of plants increased much more than the dry weight of prey added, indicating a “fertilizing effect”. Thus, animal food supply is an important limiting factor in the field. The essential component of the prey is probably its mineral content. There were significant differences between the two species of sundew. In D. rotundifolia the effect of feeding on dry weight was smaller and plants nerver showed axillary budding. However the effect on the percentage of blooming plants was more than twice as strong as in D. intermedia. Considering only the prey actually absorbed per unit of plant biomass, both species show about the same fertilizing effect. The number of fruits per unit of biomass was about twice as large in D. rotundifolia as in D. intermedia. The reasons for these differences are discussed in the light of niche segregation with respect to habitat and range of prey.

Key words

Carnivorous plantsDroseraLimiting factorCompetitionNiche segregation

Copyright information

© Springer-Verlag 1988

Authors and Affiliations

  • Martin Thum
    • 1
  1. 1.Zoologisches Institut der Universität MünchenMünchen 2Germany