Age-specific ecological life table of Spodoptera litura (F.) (Lepidoptera, Noctuidae) on groundnut

Abstract

Experiments were conducted to study the life history traits of Spodoptera litura under controlled environmental conditions on groundnut host. To construct the age-specific fecundity life tables, adults emerged on the same day were caged for oviposition and the number of eggs laid on each day was recorded. The key mortality factors involved in each life stages were also accounted. Females contributed highest number of progeny (m_x = 346.12) on 39th day of pivotal age. The net reproductive potential (R_o) was 858.52 females/female/generation with the mean generation period (T_c) of 38.86 days. The life table analysis revealed that the late instar larvae were more vulnerable to natural mortality factors (64.95%) and total mortality per cent recorded was 83.02. The various key mortality factors viz., parasitoids (Cotesia sp., Chelonus sp. and Tachinids), virus (NPV), malformed pupa and adults were recorded from the field population of S. litura from groundnut ecosystem.