Functional analysis of metals distribution in organs of the beetle Chrysolina pardalina exposed to excess of nickel by Micro-PIXE

Abstract Micro-PIXE mapping of elemental distribution within organs of Chrysolina pardalina beetle feeding on a nickel hyperaccumulating plant species Berkheya coddii , was used to check its ability to cope with excess of nickel and to study quantitative and qualitative relations between nickel and other elements in physiologically important structures. Data analysis was performed using a new PC based version of the GeoPIXE software (GeoPIXE II). The use of micro-PIXE, supported with analysis of electronograms demonstrated mechanism of Ni rejection from the insects’ body. Concretions rich in Zn, Cu, Fe, Mn, Br are formed in Malpighian tubules and in the midgut cells. Organs important for maintaining homeostasis are protected against excess of metals. Malpighian tubules play a crucial role in Ni elimination from hemolymph, further rejected through the digestive tract and in larve also with exuvia during molting. Both used methods proved that midgut cells in adults could regenerate. Such an adaptive mechanism has not been earlier described in adult beetles.