| Researchers collected early and late season eggs, separating some into component parts and incubating others for short or long photoperiods. |
| Effect of natural and artificial photoperiods and fluctuating temperature on age of first mating and mating frequency in the navel orangeworm, Amyelois transitella. |
| By rounding the hours, and then calculating morning and afternoon photoperiods, the students can easily calculate the entire day's photoperiod. |
| Growth, gonadal development and spawning time of Atlantic cod reared under different photoperiods. |
| Plasma prolactin and gonadotrophins during gonadal development and the onset of photorefractoriness in male and female starlings on artificial photoperiods. |
| Calhoun measured responses to varying photoperiods, but tested only one animal in non-normal photoperiods. |
