Reaction of leaf weevil (Phyllobius arborator (Herbst)) to increased concentration of manganese in diet was investigated in laboratory rearing with controlled temperature, humidity, and light conditions. Food for leaf weevils in rearing (leaves of birch Betula pendula Roth) was contaminated by soaking the leaves in solutions of MnCl2.4H2O with graded concentration of manganese. Direct influence of food was characterized by the consumed amount of leaves, period of feeding, and weight of P. arborator adults. At the same time, the levels of manganese in unconsumed food, excrement, and bodies of adults were determined.
Even very high content of manganese in food did not cause significantly different reaction of P. arborator adults in comparison to individuals in control treatment. No significant difference in the quantity of the consumed food, weight of adults, and duration of their feeding period was found between the treatments within the experiment. The content of manganese found in food, excrement, and adult beetles indicate that P. arborator avoided manganese intoxication through food by both—voiding manganese through the feces and sequestering it at relatively high concentrations in unspecified parts of their body.
