INFLUENCE OF CONSTANT TEMPERATURE DEGREES ON THE BIOLOGICAL CHARACTERS AND PREDACEOUS EFFICIENCY OF THE PREDATOR Rodolia cardinalis (MULSANT)

06-07-2017 14:53

Laboratory experiments were carried out to study the influence of different constant temperature in the insectary of the economic entomology Department, Faculty of Agriculture, Mansoura University.
The larval stage of the predator Rodolia cardinalis (Mulsant) when reared on the third nymphal instar of Icerya aegyptiaca Douglas under three constant temperature 20±1, 24±1 and 28±1˚c lasted an average of 20.7±0.34, 11.8±0.34 and 7.3±0.49 days, respectively.
The average of the total consumption for larval stage when reared on I. aegyptiaca at 20, 24 and 28˚c reached 28.80±2.18; 60.50±2.48 and 53.45±3.27 individuals/ larva. Meanwhile, results showed that, the highest total consumption for larva during its four larval instars when reared at 24˚c followed by 28˚c with highly significant differences.
The calculated biomass from (Carbohydrates, Lipids and protein) consumed by one predator larva during its larval stage at 20, 24 and 28˚c reached an average of (38.30, 36.86 and 21.89 mg.), (80.47, 77.44 and 45.98 mg.) and (71.09, 68.42 and 40.62 mg.), respectively.
Longevity for female and male when fed on the third nymphal instar of I. aegyptiaca as preys under different constant temperature of 20, 24 and 28˚c lasted an average of (50.4±2.16 and 33.4±2.20), (46.4±2.12 and 29.0±2.09) and (22.4±1.29 and 15.1±0.82 days), respectively.
The average of the total consumption for adult female fed on I. aegyptiaca reached 140.6±5.72, 328.2±10.90 and 218.3±9.14 individuals/ female when reared under 20, 24 and 28˚c, respectively, with highly significant differences. Also, for adult male reached 50.3±4.95, 145.8±6.84 and 107.8±7.14 individuals/ male, respectively, with highly significant differences.
The highest total consumption for adult female was recorded during the oviposition period especially, under 24˚c (289.0±10.53 individuals/ female) and resulting, the number of deposited eggs/ female was the highest (354.30±19.90 egg/ female), it could be concluded that the temperature degree of 24˚c was the best for mass rearing of R. cardinalis because the female layed the highest eggs on this degree