Experimental Sexual Photoperiodicity in the Male Turtle, Pseudemys elegans (Wied)

Abstract

Increased artificial illumination started on Nov. 18, 1936, on [male] turtles at the crest of a spermatogenic cycle, caused an inhibition of this cycle, and induced a new cycle. Controls kept in a cool room and in darkness showed no inhibition of the original cycle. Controls receiving only normal daylight, and kept under the same conditions as those turtles receiving added light fell into 2 groups: a) those with no inhi-bition of the original; b) those that showed a beginning of a new cycle, which, however, lagged far behind that of the turtles which got increased light. All the exptl. ani-mals gave a uniform response, i.e., a new spermatogenic cycle.