Laboratory Study of Life Cycle and Feeding Rate of the Beetle Cybocephalus fodori minor (Col.: Cybocephalidae) Predator of Pistachio Oyster Shell Scale Lepidosaphes pistaciae (Hom.: Diaspididae)

The predatory beetle Cybocephalus fodori minor has recently been reported in Iran. Also few studies have been reported on life cycle of Cybocephalus beetles, especially on that of C. f. minor. Thus, the life cycle and feeding rate of this predatory beetle was studied on pistachio oyster shell scale, Lepidosaphes pistaciae under laboratory conditions (temperature: 25 ± 2 °c relative humidity: 65 ± 5% and photoperiod: 16:8 L: D/h). Life cycle of C. f. minor was completed at six stages including egg, three larval instars, pupa and adult. Duration of the development for one generation (not considering preoviposition period) was 43-46 days for males and 38- 42 days for females. The developmental time length for the egg, larval instars1-3, pupa, male and female adults longevity, preoviposition and postoviposition periods was 8.8 ± 0.1, 5.2 ± 0.1, 34 ± 0.1, 6.8 ± 0.1, 17.3 ± 0.3, 59.2 ± 2.2, 65.8 ± 3.1, 6.8 ± 1.6 and 3.5 ± 0.5, respectively. Average fecundidity (number of eggs laid by a female per her life time) was 64.7 ± 6.2. Sex ratio in the laboratory and in the field was 1:1. Daily feeding rate for the female and male adults, larval instars feeding on adult female scale was 7.1 ± 3.5, 6.9 ± 2.2, 1.8 ± 0.2, 3.7 ± 0.2 and 5.9 ± 0.3, respectively. These parameters were also determined when those stages were fed on the eggs and second nymphal stages of pistachio oyster shell scale. Adult beetles over 60 days exhibited the highest feeding on this scale.