Attraction and aggregation behaviour of predatory nematodes, Mesodorylaimus bastiani and Aquatides thornei (Nematoda: Dorylaimida)

Observations were made on the attraction and aggregation behaviour of two predatory nematodes Mesodorylaimus bastiani (Dorylaimida: Dorylaimidae), and Aquatides thornei (Dorylaimida: Nygolaimidae) at feeding sites using saprophagous and plant parasitic nematodes as prey. Parameters viz., time taken by predators to form the feeding sites, number of the feeding sites, duration of feeding, duration of post-feeding aggregation, duration for which the feeding sites existed, number of predators present, number of predators feeding upon a prey, number of predators showing during-feeding and post-feeding aggregation at the feeding sites were selected for the present study. Six to ten individuals of predators were present per feeding site but the number of feeding predators was always more than those showing during-feeding aggregation at the site. Feeding sites, which were formed earlier showed prolonged post-feeding aggregation of predators. Different values for the rate of site formation, number of sites formed, and aggregation activities during and after feeding at the feeding sites of the two predators reflected differential predatory potentials.