تاثیر دو گونه میزبان گیاهی روی شاخص‌های تغذیه شب‌پره برگخوار شمشاد Cydalima perspectalis (Lepidoptera: Crambidae) در پرورش انفرادی و گروهی

The box tree moth Cydalima perspectalis (Walker) (Lepidoptera: Crambidae), originated from Eastern Asia, has been recently introduced to Iran. This invasive pest caused severe damage on boxwood species in Hyrcanian forests. In the current research, the effect of two boxwood species, Buxus hyrcana (Hyrcanian boxwood) and B. microphylla (littleleaf boxwood) were evaluated on the nutritional indices of C. perspectalis larvae using fresh and dry weights in individual and group rearing methods. The experiment was conducted at 26 ± 1 ºC, relative humidity of 75 ± 5% and 16: 8 (L: D) h. According to results, the mean fresh weight gained by larvae on B. hyrcana and B. microphylla in individual method were 0.13 and 0.12 g, respectively. In group rearing method, the mean fresh weight gain of larvae were evaluated to be 0.14 and 0.06 g on mentioned boxwood species, respectively. Furthermore, the dry weight gain of larvae fed on B. hyrcana was significantly higher than on B. microphylla in both individual and group rearing methods. However, the fresh and dry ingested food of larvae did not significantly differ on the plant species in both rearing methods. Based on the results, the relative consumption rates (RCR) on two host plants (fresh and dry weight) ranged from 1.74 to 6.00 g/g/day and the relative growth rate (RGR) of C. perspectalis varied from 0.10 to 0.35 g/g/day in the individual and group rearing methods. The results of fresh and dry weights in both rearing methods showed that the efficiency of conversion of digested food (ECD) and the efficiency of conversion of ingested food (ECI) of C. perspectalis fed on B. hyrcana were significantly higher than those on B. microphylla. However, approximate digestibility (AD) of C. perspectalis fed on B. hyrcana was significantly lower than on B. microphylla base on fresh/dry weight in two rearing methods. In similar trend, the consumption index (CI) of larvae on B. hyrcana were 1.30 and 1.18 in fresh weight and 2.28 and 2.07 in dry weight in the individual and group rearing methods, respectively, which were significantly lower than CI values of the box tree moth on B. microphylla. These findings of nutritional indices of C. perspectalis on boxwood species, B. hyrcana and B. microphylla, would be useful in comprehensive understanding of the relationships between the host plants and the invasive pest.