Prey consumption by larval and adult stages of the entomophagous ladybird Serangium parcesetosum Sicard (Col., Coccinellidae) of the cotton whitefly, Bemisia tabaci (Genn.) (Hom., Aleyrodidae), at two different temperatures Abstract The entomophagous ladybird, Serangium parcesetosum Sicard (Col., Coccinellidae) appears to be a promising predator against the cotton whitefly, Bemisia tabaci (Genn.) (Hom., Aleyrodidae). Knowledge about its consumption of B. tabaci is incomplete. The present study was undertaken to determine the potential use of this predator in biological control programs. The daily and total prey consumption of S. parcesetosum through the entire development of the larval instars as well as during three different periods of longevity of adult females and males feeding on nymphs or puparia of B. tabaci as prey was examined. In addition, the daily prey consumption of the adult females where the number of B. tabaci puparia was altered was studied at two different temperatures in the laboratory. The results showed that the mean daily prey consumption of nymphs or puparia of B. tabaci by larval instars of S. parcesetosum increased gradually as development progressed at both temperatures. Significant differences were found in the mean total prey consumption among the different predatory larval instars. In total, S. parcesetosum consumed during its entire larval development significantly more nymphs than puparia; at 18°C it consumed a mean of 1,566.1 ($) and 1,443.9 (#) nymphs or 280.0 ($) and 250.8 (#) puparia, while at 30°C, it consumed a mean of 1,119.1 ($) and 979.9 (#) nymphs or 188.2 ($) and 171.6 (#) puparia. Over the three studied periods of the adult stage of S. parcesetosum, the mean daily prey consumption by the females and males fluctuated irregularly at both temperatures. At 18°C and 30°C, both females and males consumed significantly more nymphs than puparia. No significant differences were found between females and males with respect to consumption of nymphs, although significant differences were found between the sexes with respect to consumption of puparia, but at 18°C only. The mean total prey consumption over the three studied adult stages

Serangium parcesetosum Sicard (Col., Coccinellidae) is considered one of the important predators of whiteflies. However, knowledge about its preferences for different prey stages, species and parasitized prey is still lacking in the literature. The present work investigated the preferences of S. parcesetosum for different stages of B. tabaci, different prey species and B. tabaci parasitized by Encarsia formosa Gahan (Hym., Aphelinidae) by prey consumption at different temperatures in the laboratory. Results showed that L 2 and L 4 predatory instars of S. parcesetosum preferred puparia to nymphs and eggs of Bemisia tabaci (Genn.) (Hom., Aleyrodidae). The mean daily prey consumption was 5.1-9.0, 4.5-6.2 and 3.6-4.3 by L 2 and 6.4-9.7, 5.5-8.5 and 2.5-7.5 by L 4 for puparia, nymphs and eggs, respectively. Adult females, however, indicated a significantly greater preference for both puparia and nymphs, consuming a daily mean of 6.4-7.5 puparia and 5.1-6.7 nymphs, but only 3.0-4.7 eggs. At 18 and 30°C, all S. parcesetosum stages tested significantly preferred B. tabaci and Trialeurodes vaporariorum Westwood (Hom., Aleyrodidae) over the other three prey species offered. At both temperatures, all predatory stages preferred B. tabaci to T. vaporariorum, the L 2 instar at 18°C, showing significantly more preference for B. tabaci than T. vaporariorum. In contrast, very few individuals were consumed from Aphis gossypii Glover (Hom., Aphididae), Frankliniella occidentalis (Pergande) (Thys., Thripidae) and Tetranychus urticae Koch (Acari, Tetranychidae). At 18°C, a daily mean of 7.5-8.0, 6.6-9.0 and 6.7-8.1 B. tabaci as well as 5.3-6.4, 5.4-7.8 and 5.6-6.3 T. vaporariorum was consumed by L 2, L 4 and adult females, respectively, while at 30°C, L 2 , L 4 and adult females consumed a mean of 9.3, 8.8-9.7 and 8.3-9.7 B. tabaci/day as well as 8.3-9.0, 7.8-9.1 and 5.5-8.4 T. vaporariorum/day, respectively. S. parcesetosum L 2 and L 4 instars as well as adult females and males at both studied temperatures showed a significant tendency to avoid B. tabaci puparia after 5 days of parasitism by E. formosa and preferred to feed on unparasitized whiteflies. At 18°C, the mean daily consumption was 8.7 and 0.2 (L 2 ), 11.1 and 0.6 (L 4 ), 12.1 and 1.0 ($$) as well as 10.5 and 0.2 (##), while at 30°C the means were 15.9 and 0.5 (L 2 ), 19.8 and 1.0 (L 4 ), 18.9 and 1.2 ($$) as well as 17.4 and 0.6 (##) from unparasitized and parasitized B. tabaci puparia, respectively.

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