SPERM DRINKING BY FEMALE CATFISHES - A NOVEL MODE OF INSEMINATION

We report on unique reproductive behaviour and a new mode of egg insem ination in a small catfish Cordoras aeneus (Callichthyidae). A male co urts a female by presenting his abdomen to her. Before releasing eggs, the female attaches her mouth to the male's genital opening and direc tly drinks his sperm. The sperm pass through her intestine and are dis charged together with eggs into the 'pouch' formed by her pelvic fins. Thus, eggs are mixed with fresh non-dispersed sperm in an enclosed sp ace, ensuring effective insemination. This mode of insemination is nov el to fishes, but is likely not restricted to catfishes of the genus C orydoras.