پارامترهای جمعیتی پروانه برگخوار سفید بلوط Leucoma wiltshirei Collentte (Lep.: Erebidae) طی چهار نسل متوالی در شرایط طبیعی

Since destructive outbreak in oak forests of Iran, Leucoma wiltshirei Collenette (Lep.: Erebidae) has been named as “white demon”. In the present study, population parameters of four consequence generations of this pest were investigated under natural field conditions at oak forests of Basht county (30° 32ʺ N, 51° 29ʺ E, 744 m.a.s.l.), Kohgiluyeh and Boyer-Ahmad province. In each generation, the experiments were conducted with fifty same-aged individuals; separately transferred on an oak branch (50 cm length). The individuals were separately surrounded with a two-layer mesh bag. During pre-adult stages, all replications were checked every other day and their development and survivorship were monitored. After adult emergence, males and females were paired and each couple was placed into a mesh bag. The fecundity and survivorship of female moths together with the survivorship of male ones were daily recorded until the death of last individual. Age-stage twosex procedure was utilized for life table construction. The values estimated for Gross Reproductive Rate (GRR) at 1th, 2nd, 3rd, and 4th generations were 111.05, 139.39, 111.71, and 52.04 (female offspring), respectively. The Net Reproductive Rate (NRR [R0]) had the highest value at 2nd generation (67.69 female offspring). The lowest amount of this parameter was calculated as 15.83 (female offspring) at 4th generation. The intrinsic rate of increase (r) was estimated as 0.018, 0.097, 0.085, and 0.063 (day-1) for four consequent generations, respectively. The finite rate of increase had the highest (1.102 day-1) and lowest (1.018 day-1) values at 2nd and 1th generations, respectively. The mean generation time (T) was calculated as 223.84, 43.31, 46.01, and 43.78 (day) for different generations, respectively. These findings developed our knowledge about field biology of L. wiltshirei and could be so helpful for sustainable management of this destructive pest.