Foraging is a well-established behavior in animals, less so in plants. However, foraging tactics are implicated in the growth pattern of many clonal plants. The genet gains a fitness benefit when successive ramets are rooted in high nutrient versus low nutrient patches. This control over patch occupation may be indicative of foraging. Moreover, the status of the mother ramet can substantially alter the way stolons are initiated for searching. Alpert has provided evidence of plasticity and division of labor in the dune strawberry, F chiloensis. Here we report a preliminary experiment to test the nature of plasticity in another strawberry species, F vesca. We are particularly interested to know if this reaction to the environment is indicative of plant foraging by clonal plants, as detailed by the optimal foraging theory. We gathered baseline data to determine how the woodland strawberry develops as an experimental system, specifically focusing on stolon initiation in varying environments. Individual ramets were randomly assigned to block light/fertilizer, light/no fertilizer, dark/fertilizer, or dark/no fertilizer treatments for 30 days. Daughter ramets were not allowed to root. Upon harvest, number of stolons, stolon length, and total stolon dry mass were recorded and analyzed.
Results/Conclusions
We found that significantly more stolons were produced by individual ramets by harvest in response to light. Application of fertilizer produced similar results. The total length of stolons per individual was significantly longer in fertilized plants than unfertilized plants. The interaction of light and fertilizer on total stolon length was also significant. Furthermore, per gram, unfertilized plants produced longer stolons than fertilized stolons. These findings are not consistent with the predictions of foraging in the clonal plant, however we did not allow plants to root, therefore individual ramets behaved as non-clonal plants. Foraging behaviors were not permitted to occur during this preliminary experiment. Additionally, many clonal behaviors only manifest in heterogeneous environments. However, we were particularly interested in the implications of stolon thickness in potential foraging tactics in response to the environment of the mother ramet. Subsequent experiments will investigate these issues.
