Age-specific life tables of aonidiella aurantii (Maskell) (hemiptera: Diaspididae) and its parasitoid aphytis melinus debach (hymenoptera: Aphelinidae)

Abstract

Biological parameters of the California red scale (Aonidiella aurantii [Maskell] [Hemiptera: Diaspididae]) were determined under laboratory conditions at 3 different temperatures (20, 23, and 27 °C) on butternut squash (Cucurbita moschata Duchesne ex Lamarck) (Cucurbitaceae), while the biological parameters of its parasitoid Aphytis melinus DeBach (Hymenoptera: Aphelinidae) were conducted at 27 °C. The survival of A. aurantii ranged between 80.0% and 88.3%. The highest mortality was recorded during the adult stage, with mortalities ranging between 12% and 20%. On C. moschata, the total development time was 93.1 ± 9.73, 81.8 ± 7.13, and 65.7 ± 6.37 days, while the adult longevity was 54.65 ± 0.71, 47.05 ± 0.97, and 39.35 ± 1.07 days at 20, 23, and 27 °C, respectively. The oviposition period of A. aurantii was 44.3 ± 0.51, 40.65 ± 0.41, and 34.5 ± 0.45 days at 20, 23, and 27 °C, respectively. Average fecundity was 73.25 ± 1.827, 109.7 ± 3.569, and 129.35 ± 4.564 individuals at 20, 23, and 27 °C, respectively. For A. melinus, adult longevity was 19.24 ± 0.73 days, and average fecundity 62.7 ± 2.81 eggs at 27 °C. The preoviposition period was 0.82 ± 0.05 days, oviposition period was 15.7 ± 0.52 days, and postoviposition period was 2.21 ± 0.09 days. The intrinsic rate of increase (rm) of A. melinus (0.188 ♀/♀/day) was significantly greater than that of A. aurantii (0.080) at 27 °C. These laboratory results demonstrated that A. melinus is an effective parasitoid for decreasing A. aurantii populations. Fecundity of A. aurantii and A. melinus was determined with the Enkegaard equation. The best-fit parameters of fecundity were calculated as a = 0.410, b = 0.099; a = 0.624, b = 0.098; a = 0.661, b = 0.091; a = 1.190, b = 0.179 for A. aurantii at 20, 23, and 27 °C, and A. melinus at 27 °C, respectively.