This study evaluated the Arctiinae fauna in a fragment of primary forest in Altamira, Pará, Eastern Amazonia, Brazil. The moths were sampled during two years (from August 2007 to July 2009) with a light trap. The following parameters were measured: richness, abundance, constancy, diversity and evenness indices (Shannon H ‘and E') and Brillouin (H and E), and dominance index of Berger-Parker (BP). The richness estimatives were made by nonparametric procedures, Bootstrap, Chao 1, Chao 2, Jackknife 1, Jackknife2 and Michaelis-Mentem. Four hundred and sixty-six individuals of 78 species of Arctiinae were captured, of which twelve are new records for Pará State. Values of parameters analyzed for the entire period were: H ‘= 3.08, E' = 0.708, H = 2.86, E = 0.705, and Sp = 0.294. Communities of the less rainy months were more diverse. Estimators predicted an increase between 17 to 253 in species richness.
Biodiversity; Moths; Neotropical Region; Noctuoidea