Aflatoxins (AFs) are considered to play important functions in species ofAspergillussectionFlaviincluding an antioxidative role, as a deterrent against fungivorous insects, and in antibiosis. AtoxigenicFlaviare known to degrade AF-B1 (B1). To better understand the purpose of AF degradation, we investigated the degradation of B1 and AF-G1 (G1) in an antioxidative role inFlavi. Atoxigenic and toxigenicFlaviwere treated with artificial B1 and G1 with or without the antioxidant selenium (Se), which is expected to affect levels of AF. After incubations, AF levels were measured by HPLC. To estimate which population would likely be favoured between toxigenic and atoxigenicFlaviunder Se, we investigated the fitness, by spore count, of theFlavias a result of exposure to 0, 0.40, and 0.86 µg/g Se in 3%-sucrose cornmeal agar (3gCMA). Results showed that levels B1 in medium without Se were reduced in all isolates, while G1 did not significantly change. When the medium was treated with Se, toxigenicFlavisignificantly digested less B1, while levels of G1 significantly increased. Se did not affect the digestion of B1 in atoxigenicFlavi, and also did not alter levels of G1. Furthermore, atoxigenic strains were significantly fitter than toxigenic strains at Se 0.86 µg/g 3gCMA. Findings show that while atoxigenicFlavidegraded B1, toxigenicFlavimodulated its levels through an antioxidative mechanism to levels less than they produced. Furthermore, B1 was preferred in the antioxidative role compared to G1 in the toxigenic isolates. The higher fitness of atoxigenic over toxigenic counterparts at a plant non-lethal dose of 0.86 µg/g would be a useful attribute for integration in the broader biocontrol prospects of toxigenicFlavi.