YIELD AND QUALITY OF CARMINIC ACID OF Dactylopius coccus Costa IN DIFFERENT HEIGHT LEVELS OF THE NOPALOTECA

Abstract

Dactylopius coccus is an important insect for commerce, as the source of a natural dye called carminic acid. For its commercial production in captivity, rearing has been promoted in cladodes suspended at different heights in a system called “nopaloteca”. However, it is unknown whether insect quality and yield vary at different levels. The objective of this study was to determine the influence of height level in a “nopaloteca” and the harvest index of carminic acid concentration (CAC, %) and fresh weight (FW, g) of D. coccus. Insect rearing was carried out in a wooden “nopaloteca” (3x3 m) with four height levels (0.5, 1.0, 1.50 and 2 m). During the culture cycle, temperature, relative humidity, and luminous intensity were measured daily. Adult females were collected in two development stages: pre- and post-oviposition. The highest CAC (19.2%) was obtained at 1.0 m high, although at this level the lowest FW was recorded, 3.5 g per cladode, which expresses a negative correlation between CAC and FW. Post-oviposition harvest generated a higher CAC (18.8%), although FW decreased. Relative humidity and total illumination, but mainly temperature at each level, affected quality and yield of D. coccus, though the two factors were affected differentially, indicating the presence of optimal limits for development. Under the conditions of this study, the “nopaloteca” rearing system produced an average of 4.5 g cochineal per cladode and a CAC of 17.5%. The levels evaluated caused difference in yield and quality, but the highest values were registered in the intermediate levels (1.0 and 1.5 m). The recommended harvest index to obtain more CAC was the post-oviposition phase.