the response of plants and animals by behaviour, growth, etc, to photoperiods
photoperiodism in American English
(ˌfoʊtoʊˈpɪriədˌɪzəm)
noun
Biology
the behavioral or physiological reaction of an organism to variations in the duration of light, as, in plants, by flowering or ceasing to flower, or, in certain animals, by changing the daily cycle of activities