INFLUENCE OF PHOTOPERIOD ON SOME DEMOGRAPHIC PARAMETERS AND QUALITY OF COCHINEAL INSECTS (Dactylopius coccus)

Abstract

To assess the influence of photoperiod on the development, reproduction and carminic acid content of cochineal insects (Dactylopius coccus), cohorts were established in climatic chambers on cladodes of Opuntia ficus-indica L. (Mill.); these were subjected to five photoperiod regimes: 0/24, 8/16, 10/14, 12/12 and 24/0 hours of photophase:scotophase, respectively. The photoperiod affected the duration of the life cycle, which occurred faster when the hours of darkness decreased, although the survival values were reduced. The regime with 14 hours of darkness provided the best conditions for the development and reproduction of D. coccus. The photoperiod regimes tested generated a low percentage of carminic acid (12%), so further studies are required to verify if it is the quantity and quality of light that influences the presence of the dye or the physiology of the host plant.