Lemming-Food Plant Interactions, Density Effects, and Cyclic Dynamics on the Siberian Tundra
Författare
Summary, in English
Theory predicts that trophic interactions can produce cyclic dynamics of microtine rodents, but that in addition, social interactions are necessary to create the cyclicity. We tested the induced defence hypothesis as a component driving multiannual cycles by analyzing data on Siberian lemming (Lemmus sibiricus Kerr) populations and the levels of trypsin inhibitors (TI) and free proteins (SPP) in their food plants. We collected data at 12 sites along the Palaearctic tundra coast in 1994 and correlated these measures with lemming density and cycle phase. A negative correlation between lemming density and TI/SPP in Carex was found at the 12 sites. Cycle phase tended to correlate significantly with TI/SPP, and plants being grazed by lemmings respond with some delay. Mass of pancreas, the organ producing proteolytic enzymes, co-varied negatively with TI/SPP. These findings are in accord with predictions from the induced defence hypothesis. En contrast, reproductive effort did not conform to the predictions but co-varied strongly with density. Data are in accord with theory predicting that, in addition to trophic interactions, some self-regulation is necessary to create cyclic dynamics. Our data show that the plant defence hypothesis alone is not a sufficient explanation for the cyclicity. Several factors interact, including predation, food quality (including induced defence chemicals), and intra-specific competition.
Avdelning/ar
Publiceringsår
2011
Språk
Engelska
Sidor
421-428
Publikation/Tidskrift/Serie
Arctic
Volym
64
Issue
4
Dokumenttyp
Artikel i tidskrift
Förlag
The Arctic Institute of North America
Ämne
- Biological Sciences
Nyckelord
- lemming
- cyclic dynamics
- lemming-food plant interactions
- density
- effect
- Siberian tundra
Status
Published
Forskningsgrupp
- Molecular Ecology and Evolution Lab
ISBN/ISSN/Övrigt
- ISSN: 0004-0843