Abstract
ABSTRACT The development, life table and predation rates of the predatory mites Neoseiulus womersleyi and Euseius ovalis feeding on four tetranychid mites and two kinds of pollen was studied in a chamber at 25°C, 75±5% RH and 16:8 (L:D) photoperiod. Immature stages of N. womersleyi feeding on Tetranychus urticae and T. kanzawai had shorter development duration (4.71 and 5.02 days for females, 4.77 and 5.19 days for males, respectively) than those feeding on other food sources. Immature stages of E. ovalis females feeding on Oligonychus mangiferus and T. urticae developed in 4.99 and 5.13 days, respectively, the shortest developmental duration measured. Immature stages of E. ovalis males feeding on O. mangiferus and T. urticae developed in 5.12 and 5.37 days, respectively. The longevity of N. womersleyi males (13.31 to 14.51 days) and females (17.67 to 21.81 days) feeding on T. urticae, T. kanzawai or maize pollen was longer than the longevity of N. womersleyi feeding on O. mangiferus, P. citri or loofah pollen. Euseius ovalis males (12.91 to 16.74 days) and females (16.24 to 23.77 days) feeding on O. mangiferus, T. urticae or maize pollen lived longer than E. ovalis males and females feeding on T. kanzawai or Panonychus citri or loofah pollen. Among all of the food sources tested, the fecundity of N. womersleyi was high (33.57 eggs/female) on T. urticae, but low on P. citri (17.63 eggs/female), whereas E. ovalis was high (35.86 eggs/female) on O. mangiferus and low (8.89 eggs/ female) on T. kanzawai. Sex ratio differed among food sources and ranged from 0.67 to 0.78 for N. womersleyi and from 0.68 to 0.78 for E. ovalis. In addition, female sex ratios of N. womersleyi and E. ovalis in the field also changes, higher sex ratio in June, July and November, and lower sex ratio was found in August, September and December. The highest net reproductive rate (R0 = 24.86 offspring/individual) and intrinsic rate of natural increase (rm = 0.254/day) were found in N. womersleyi feeding on T. urticae and T. kanzawai, respectively; the lowest R0 (9.88 offspring/individual) was recorded on O. mangiferus and the lowest rm (0.179/day) was on loofah pollen. When feeding on O. mangiferus, E. ovalis had a higher R0 (26.46 offspring/individual) and rm (0.256/day) than those fed on other food sources. Neoseiulus womersleyi immatures consumed 9.73 T. urticae eggs, 13.53 larvae, or 11.57 protonymphs, while gravid females consumed 12.13 T. urticae eggs, 14.37 larvae, or 12.07 protonymphs daily. Female N. womersleyi consumed a total of 218.12 T. urticae eggs, 260.85 larvae, or 222.33 protonymphs, while male N. womersleyi consumed a total of 96.39 T. urticae eggs, 112.23 larvae, or 99.65 protonymphs. When O. mangiferus larvae or protonymphs were offered to E. ovalis, immatures consumed 18.57 larvae or 17.47 protonymphs. Gravid females consumed 16.83 larvae or 12.83 protonymphs daily, with a total of 330.68 larvae or 252 protonymphs. Adult E. ovalis males consumed fewer O. mangiferus larvae (107.69) or protonymphs (91.51) than females. Conversion rate of predation to reproduce was expressed as “Food-reproduction exchange rate” of N. womersleyi was lower on T. urticae than on T. kanzawai. E. ovalis showed a higher food-reproduction exchange rate on O. mangiferus than on T. urticae.
Published Version
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