Chemical communication in Heligmosomoides polygyrus (Nematoda: Trichostrongylida): the effect of age and sexual status of attracting and responding worms and localization of the sites of pheromone production in the female

Abstract

Pheromones, specifically sex and aggregation pheromones, have been found in both immature and mature male and female Heligmosomoides polygyrus. "Heterosexual" (male–female and female–male in responder–target positions) experiments using mature, 12-day-old worms showed a significantly greater attraction to target worms than did similar experiments using immature, 9-day-old worms. "Homosexual" (male–male and female–female) experiments using mature worms were not significantly different from similar experiments using immature worms. The strength of the pheromonal system influencing heterosexual interactions appears to be dependent on the maturity of worms in both the target and responder positions, mature worms being both more attractive and more responsive than immature worms. To determine the site of pheromone production in female worms, various homogenized tissues from females were tested for their attractiveness to males. Male nematodes responded more rapidly toward homogenized uterus containing fertilized eggs than toward homogenates of fertilized eggs only, unfertilized oocytes, or the intestinal tract of female worms. The source of the female-produced pheromone seems to be the uterine epithelium.