Gel filtration with Sephadex G‐25 or Bio‐Gel P‐2 of homogenates of the sexes of the zooparasitic nematode Nippostrongylus brasiliensis revealed two fractions with pheromonal activity. One active fraction with a suggested molecular weight over 500 was found in aqueous extracts of both helminth sexes and was attractive to both sexes by in vitro bioassay. A second region of pheromone activity was found in only female Nippostrongylus and was attractive to only male helminths. A molecular weight under 400 is proposed for this region. Additionally, a third region that represented ionic weights was present in both sexes, but attracted only female worms. These results indicated that helminth to helminth attraction is present at both species and sexual levels of recognition.
ASJC Scopus subject areas
- Animal Science and Zoology