Biology and life table analysis of Nigma conducens (Arachnida: Araneae) fed on first instar larvae of Spodoptera frugiperda under laboratory conditions

The developmental biology, feeding potential, and population growth parameters of Nigma conducens fed on first instar larvae of Spodoptera frugiperda were evaluated under laboratory conditions. Both male and female spiderlings passed through five instars. The life cycle was completed in 72.18 ± 2.10 days for females and 62.80 ± 1.06 days for males, with females showing significantly longer developmental periods, longevity (80.30 ± 2.11 days), and higher fecundity (311.60 ± 18.36 eggs per female). Females also exhibited a greater total consumption rate (101.80 larvae) than males (68.30 larvae), particularly during the fifth spiderling and adult stages, reflecting higher energy requirements for growth and reproduction. Life table analysis revealed a gross reproductive rate of 237.17 offspring per female, a net reproductive rate of 168.37 females per female, and a survival rate of 90%, indicating high reproductive potential and low mortality. The intrinsic rate of increase (rm = 0.063 females/female/day) and finite rate of increase (λ = 1.06) demonstrate a moderately fast population growth, with a mean generation time of 80.58 days and a doubling time of 11 days. These findings suggest that N. conducens possesses favorable biological characteristics that support its potential use as an augmentative biological control agent against S. frugiperda.