Influence of different host plants of English grain aphid, Sitobion avenae (Hemiptera: Aphididae) on some life table parameters of ladybird, Hippodamia variegata (Coleoptera: Coccinellidae)

The effect of four host plants of English grain aphid, Sitobion avenae (Fabricius) (Hemiptera: Aphididae) including wheat, Triticum aestivum var. Tajan, barley, Hordeum vulgare var. Dasht, corn, Zea mays var. Single cross 704 and sorghum, Sorghum durra var. Speed, on some life table parameters of ladybird, Hippodamia variegata (Goeze) (Coleoptera: Coccinellidae) were evaluated under laboratory conditions at 25±1°C, 65±5% relative humidity, and a photoperiod of 16:8 h (L: D). The gross fecundity rate and gross fertility rate were 500.50, 447.06, 604.33 and 378.61 eggs/female and the net fecundity rate and net fertility rate were 412.09, 405.60, 538.54 and 309.56 eggs/female on the above-mentioned cultivars, respectively. The highest and lowest value of the net fertility rate was 538.54 and 309.56 eggs/female on corn and sorghum, respectively. Also, the values of daily reproduction rates, number of eggs laid per female per day and mean number of fertile eggs per female per day, varied from 8.20 to 7.72 eggs/female, which was minimum on sorghum and maximum on corn. The life expectancy of one-day-old adults of the H. variegata was estimated 47.90, 43.90, 52.78 and 38.60 days on the above-mentioned cultivars, respectively. The comparison of reproduction parameters of H. variegata on host plants indicated that this predator has higher reproduction potential on corn. However, the results showed that four host plant species of S. avenae were acceptable for the growth, development and reproduction of this predator.