Sex and aggregation attractants of Heligmosomoides polygyrus (Nematoda: Trichostrongylidae)

Abstract

Chemical communication in the mouse nematode Heligmosomoides polygyrus was examined in vitro. Virgin males were significantly attracted to virgin females, moving an average of 2.43 cm/h with a maximum of 60% of the males reaching target females. Female worms were moderately attracted to target males; 20% of the responding worms reached the target at an average speed of 1.07 cm/h. In the homosexual trials, 20% of responding females reached target females with an average speed of 1.70 cm/h. Homosexual experiments among males showed a slight attraction. Responding worms moved at an average speed of 0.84 cm/h but none of the migrating males reached the target. Control experiments using no attractant showed that responding worms, in the absence of any target, travelled randomly. Controls using worm products and homogenized worms showed that males reached the female incubant with an average speed of 1.17 cm/h. Experiments using more than one responding male indicated that males may inhibit the movement of other males toward the target females. There appear to be both aggregation and sex attractants in H. polygyrus as well as inhibitory chemicals produced by males which influence other nearby males.