Cellular Encapsulation in Spodoptera litura (Fabricius) Infected with Potential Entomopathogens

Background: Entomopathogens are foreign agents which elicits immune responses in insects. The insect innate immune system can identify and overcome these foreign-agents through cellular and humoral processes. Methods: The current study reports the cellular encapsulation in Spodoptera litura to different test entomopathogens including Beauveria bassiana, Metarhizium anisopliae, Bacillus thuringiensis and Nuclear Polyhedrosis virus (Sl NPV). Third instar larvae were treated with the test entomopathogens and haemolymph was collected at different time intervals i.e., 1, 3, 6, 12, 24, 48 and 72 hours after infection (HAI) to study the cellular encapsulation responses. Result: The immediate response of larvae to entomopathogens infection was a significant increase in the number of encapsules formation when compared to the untreated control i.e., B. bassiana: 51±2.52c, M. anisopliae: 42±1d, Bt: 95±1.53a, Sl NPV: 61±2.52b and control: 4±1.15e. However, after 3 days from the immune challenge, the number of encapsules formed was significantly lower i.e., B. bassiana: 11±1.53b, M. anisopliae: 9±1b, Bt: 21±1.53a, Sl NPV: 10±1b and control: 0.