Musca depicta

[1][2] James N. Hogue, writing in the Encyclopedia of Insects, lists the following reasons behind musca depicta: as a jest; to symbolize the worthiness of even minor "objects of creation"; as an exercise in artistic privilege; as an indication that the portrait is post mortem; and as an imitation of works of previous painters.

[1] Many art historians argue that the fly holds religious significance, carrying connotations of sin, corruption or mortality.

[3] Another theory is that Renaissance artists strove to demonstrate their mastery in portraying nature, with André Chastel writing that musca depicta became as an "emblem of the avant-garde in painting" at the time.

[4] There exist several anecdotes from the biographies of various artists who, as apprentices, allegedly painted a fly with such skill as to fool their teacher into believing it was real.

[6] Trompe-l'œil flies are recognized in over twenty Netherlandish, German, and north Italian paintings dated between 1450 and the 1510s, and are analysed by André Chastel in a book eponymously dedicated to musca depicta.