Responses of Cecropia to experimental removal of Mullerian bodies
Functional Ecology
1994
Journal Article
8
1
22-28
light myrmecophytism nutrients resources symbiosis plants trees Cecropia Cecropiaceae experiments ecology plant-animal interactions ant-plant interactions morphology animals invertebrates arthropods insects ants Madre de Dios Bibliography
1. Myrmecophytic Cecropia trees feed and house ants, presumably in exchange for protection from herbivory. These plants produce ant rewards in the form of Mullerian bodies (MB), glycogen-rich and protein-containing corpuscles located on trichilia at the bases of leaf petioles. Because of indirect evidence for the costliness of MB, we conducted experiments to determine whether plants respond to their removal (simulating the presence of ants) and accumulation (imitating the absence of ants) by altering rates of their production. 2. In greenhouse experiments with plants cultivated at intermediate nutrient levels, MB production rates were significantly higher on plants from which the MB were removed than on control (MB accumulation) plants. This result held for both short-term observations and for observations over full trichilia life spans, as well as for plants growing under different light regimes. In contrast, rates of MB production were not significantly affected by MB removal in experiments conducted under higher or lower nutrient levels. 3. We hypothesize that these plants may economize resources by controlling MB production in response to the presence or absence of ants, and we suggest reasons why this capacity may fail at particularly low and high nutrient levels.