Comparative study of the morphology and biology of Dactylopius coccus Costa y D. opuntiae (Cockerell) (Hemiptera: Dactylopiidae), two species present in the Valencian Community.
The species of the family Dactylopiidae (or cochineal insects) are known firstly by the pigment contained in its body, carminic acid, and secondly as biological control agents of certain species of Opuntia. Cochineal insects are plant pest of Cactaceae and can be found mainly in two genera of cacti: Opuntia Mill. and Nopalea Salm-Dyck. In the Valencian Community, two species of Dactylopiidae are present, Dactylopius coccus Costa and D. opuntiae (Cockerell), where they are been detected for the first time. We have performed a comparative morphological study of the two cochineal insects, by characterizing all developmental stages (eggs, first instar, second instar, adult females and prepupal, pupal and adult males) highlighting the peculiarities of each one. It also provides data on the biology of the two species and the damage done in Opuntia ficus-indica Mill., considered an invasive species in Spain. We studied population dynamics of D. coccus from early April until late November of 2008 and we detected two annual generations followed by a partial third generation. We carried out infestations of healthy cladodes with D. coccus outdoors and with D. opuntiae in breeding chambers. At 22°C and 58.62 mm of rainfall, D. coccus needed 78 days to complete development and 87 days for completion of a generation. At 25°C and 60% H.R, D. opuntiae needed 55-60 days to complete a generation, approximately thirty days shorter than D. coccus. The damage to the plant caused by D. opuntiae was more severe and appeared more rapidly than those produced by D. coccus.