Observations on the predation ability of Aporcelaimell us nivalis (Altherr, 1952) Heyns, 1966 (Nematoda: Dorylaimida)

Abstract

Predation by Aporcelaimellus nivalis depended largely on chance encounters with the prey but the pre-feeding attraction and aggregation of up to 7 predators around an already injured prey at a feeding site is an indication of positive perception of prey body fluids. Prey catching and feeding mechanisms comprised five distinct phases viz., encounter with prey, attack response, attack, salivation/extra-corporeal digestion and ingestion/feeding. Rate of predation remained unchanged over a period of eight days but prey number, temperature, agar concentrations, starvation of the predators, type of the prey etc., determined predation. A. nivalis preferred second stage juveniles of Meloidogyne incognita (Kofoid & White, 1919) Chitwood, 1949 and Heterodera mothi Khan & Husain, 1965 to other species of prey nematodes. No predation took place when Hoplolaimus indicus Sher, 1963, Helicotylenchus indicus Siddiqi, 1963 and Hemicycliophora sp. were used as prey; thick cuticle, body annulations and toxic or unfavourable prey secretions were considered the likely cause. Adult (male and female) A. nivalis killing maximum number of prey nematodes was the most active predator stage.