Evolution of the mineral concentration and bioaccumulation of the black soldier fly, Hermetia illucens, feeding on two different larval media

Intensive black soldier fly (BSF) Hermetia illucens (Diptera: Stratiomyidae) rearing has a great importance for the feed industry. The objective of the present work was to perform a systematic study about the effect of the feeding media on the concentration and bioaccumulation factor (BAF) of Ca, K, Mg, Na, Cr, Cu, Fe, Mn, Ni and Zn in BSF fractions. Therefore, the evolution of the concentration of these elements has been studied along the stages of the BSF life cycle (larva, pupa and adult) as well as during its growth (exuviae) and metamorphosis (empty puparia). Two diets consisting of beer bagasse and commercial hen feed moistened with water have been chosen. An inductively coupled plasma optical emission spectrometer has been used to perform the elemental analyses. The obtained results demonstrated that the behaviour was generally, similar for all the elements studied, i.e. an accumulation in exuviae and puparia followed by their further elimination. Moreover, no significant differences in the results as a function of the feeding media have been found. This may be attributed to the fact that the chosen diets were equally favourable for this insect’s growth. The obtained concentrations have been expressed on a dry as well as a wet sample basis. BAF results also suggested that exuviae and puparia could be used as supplements or as bioactive compounds.