Location and behavioral effects of lectin binding on entomopathogenic nematodes with different foraging strategies

Abstract

Lectins have been used to locate and ascribe a function to sensory organs of nematodes. We had two objectives: (1) to determine the location of carbohydrate exudates on the surface of three species of entomopathogenic nematodes with different foraging strategies and (2) to evaluate the importance of carbohydrates in host finding and recognition.Steinernema carpocapsae finds hosts by ambushing, and most individuals respond poorly to host cues. No specific areas of lectin binding were recorded for this species. Wheat germ agglutinin bound specifically to the anterior region ofHeterorhabditis bacteriophora and to the anterior and posterior ofS. glaseri. These two nematode species are cruise foragers and are highly responsive to host cues. The behavioral effects of lectins varied. None of the species' responses to volatile host cues was affected.S. carpocapsae's rate of attachment during ambushing was increased by treatment with WGA, and this effect was negated by treatment with a competing sugar (N-acetylglucosamine). The infectivity ofS. glaseri in an assay that required movement through 5 cm of sand to find the host was significantly decreased by treatment with WGA.