Role of prey attractants in food finding behaviour of dorylaim predators, Laimydorus baldus and Discolaimus major (Nematoda: Dorylaimida)

Observations were made on the role of prey attractants in the food finding behaviour of two species of dorylaim predators viz., Laimydorus baldus and Discolaimus major using prey nematodes belonging to different trophic groups viz., saprophagous, virus-vectors, predators, epidermal, endodermal, migratory, semi-endodermal and cortical feeders. The attractants emitted by excised and non-excised prey individuals elicited positive and significant response of L. baldus and D. major. Excised prey individuals were more attractive to predators. Rhabditis sp., Basiria graminophila, Hirschmanniella oryzae, Anguina tritici, Pnralongidorus citri, Longidorus sp., Hemicriconemoides mangiferne and D. major were most attractive whereas Acrobeles sp., Helicotylenchus indicus, Tobrilus sp., Tylenchorhynckus mnshhoodi, Xiphinema basiri, Mesodorylaimus bastiani, Heterodera mothi and Hemicycliophora dhirenrlri were least attractive prey. The differential attraction responses of predators towards different species of prey were attributed to the differences in the inherent behaviour of predators, their preference for a particular species of prey, chemical composition, concentration, quality and quantity of prey, kairomones, minimum perceptible attraction gradient (MPAC) formed by prey kairomones and minimum response threshold (MRT) of the predators.