The general aim of this work was to study lakes\u2019s benthic communities, particularly Chironomids (Diptera Chironomidae), to select the environmental factors correlated to their diversity and distribution and to provide information about their ecology. A self-organizing map analysis (SOM) was carried out to ordinate sites (samples from 50 Italian lakes) according to macroinvertebrate community composition. Environmental variables were also included in the two dimension maps to highlight which factors are associated with site-taxa distribution (dissolved oxygen and nutrient content were selected). Within species with an indicator role of hypoxia, high nutrient amount, inorganic and organic pollution, the Chironomid Chironomus riparius Meigen 1804 was selected. A first series of experiments were carried out in lab on IV-instar larvae to investigate the role of the respiratory pigment hemoglobin and of the enzyme alcohol dehydrogenase in survive hypoxia and anoxia. A second series of experiments were carried out always on IV-instar larvae to investigate the role of five candidate genes (hsp10, hsp40, hsp70, hsc70 and cyp450) in toxic resistance (Cu and azadirachtin) (Real Time PCR analysis). Overall more information on autoecology of Chironomids was given by this study, and new data on potential biomarkers useful in biomonitoring of lakes
