On some factors influencing the population dynamics of Spodoptera littoralis (Boisd.), Sp. exigua (Hbn.), Syngrapha circumflexa (L.), Autographa gamma L., and Heliothis armigera (Hbn.) (Lep., Noctuidae) in Egypt
1989
Etmany, A. A. M.
Mating, sex ratio and age of the wild populations of five important pest Noctuidae were studied in Fayoum, Egypt, using light trap catches. Of the field collected female Sp. littoralis in the 1986/87 season, 86.5% mated; 49.5% of mated females multiple mated; and the ratio of males was 54.8%. Two peaks of mating activity were observed, the first in June with a total of 616 copulations, and the second in August with a total of 374 copulations. In the 1987/88 season, 86.2% of females mated; 49.9% of mated females multiple mated; and the ratio of males was 55.5%. One peak of mating activity was observed in May with 430 copulations. Most mated females in both seasons were mainly young and medium aged, while non‐mated females were mostly young. The mean number of spermatophores per mated female was 1.72 and 1.80 for 1986/87 and 1987/88 seasons, respectively. For Sp. exigua, wild moths were collected for one year where 82.5% of the females mated; 31.1% of the mated females multiple mated; and the ratio of males was 56.5%. The peak of mating activity was in May. Most of the mated, non‐mated females and most of the males were in the young age group. Data for Syn. circumflexa, A. gamma, and H. armigera were obtained from one year field collected moths. Of Syn. circumflexa 23.6% of females mated; 9.4% of mated females multiple mated; and the ratio of males was 56.3%. The average number of spermatophores/mated female was 1.13. Of A. gamma field collected moths, 61.0% of females mated; 39.1% of mated females multiple mated; and percent males was 60.1. The average number of spermatophores/mated female was 1.95. Of H. armigera field collected adults, 50% of females mated; 11.8% of mated females multiple mated, and percent males was 50.7. The average number of spermatophores/mated female was 1.18.
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