Numerical Analysis of the Aggregation Behavior of Discolaimus major and Laimydorus baldus (Nematoda: Dorylaimida) at Feeding Sites

Abstract

Pre-feeding and post-feeding attraction and aggregation activities of the dorylaim predators, Discolaimus major and Laimydorus baldus were studied at feeding sites using the following parameters: the number of feeding sites formed by a predator, the duration the feeding site existed, the duration of actual feeding done by the predators, the duration of post- feeding aggregation by predators, the number of predators feeding or showing pre-feeding or post-feeding aggregation, and the rate of site formation. Aggregation behavior of predatory nematodes was analyzed numerically with the help of mathematical equations. D. major and L. baldus showed different values for each of the abovementioned parameters. On an average, 2-9 individual predators were present per feeding site, but the number of feeding individual predators was always more than those showing pre-feeding aggregation at the site. Predators showed prolonged post-feeding aggregation at sites which were formed earlier. Eesophageal secretions of predators released during extra-corporeal digestion, lingering attractants left by the consumed prey individuals, and the concomitant effect of both kinds of secretions in addition to the predator’s own body secretions emanating from at the feeding site were responsible for pre-feeding and post-feeding attraction and aggregation at the feeding site. Different values for the rate of site formation, number of sites formed, and pre-feeding and post-feeding aggregation activities at a feeding site reflected differential predatory and neurosensory abilities of the predators.