Studies in West Pakistan on the biology of one Nitidulid species and two Coccinellid species (Coleoptera) that attack scale insects (Hom., Coccoidea)

Abstract

One Nitidulid species,Cybocephalus semiflavusChamp, and two Coccinellid species,Chilocorus nigritus(F.) andSimmondsius pakistanensisRafiq Ahmad & Ghani, commonly attack Diaspididae in West Pakistan. The known distribution and prey of each species are reviewed, and new records from West Pakistan given. The immature stages are described.The development ofCybocephalus semiflavusfrom egg to adult was completed in 37–41 days atc. 26°C. Mating occurred 3–5 days after emergence and oviposition began 3–6 days later, 15–69 eggs being laid. An individual adult could consume up to 47 Diaspidid eggs daily, but all Diaspidid stages were attacked. In the field the predator persisted at low prey densities, but onAonidiella orientalis(Newst), the preferred prey, its population rose in proportion to that of its prey.The development ofS. pakistanensistook 32–41 days from egg to adult atc. 24°C when fed onA. orientalisandQuadraspidiotus perniciosus(Comst). Mating was 8–11 days after emergence and oviposition began 6–11 days later, 153–242 eggs being laid. An individual could consume up to 35Leucaspis coniferarum(Hall & Williams) daily. The predator was abundant during April-May, but later its effect was limited byTetrastichus epilachnae(Giard).Atc. 24°CChilocorus nigrituscompleted development from egg to adult in 33–40 days. Mating was 4–7 days after emergence, and oviposition began 8–13 days later, 228–351 eggs being laid.C. nigritusattacked several species of Diaspidids, an individual consuming up to 41 scales daily. The adults congregated on banyan trees during November-March in the coastal area and during September-June in the foothills, but dispersed to scale-infested plants at other times of year.