Beschreibung:
<p>The pheromone fraction that elutes at Kav 0.64 in gel filtration showed significantly reduced activity for the male's locomotor response when obtained from 10-day-old, or older, female Nippostrongylus brasiliensis. This fraction, obtained from males and females that were admixed prior to extraction, revealed a sex-ratio dependent increase in pheromone activity at 50%:50% male:female according to the male's locomotor response. The female's response to mixed sex pheromone at Kav 0.64 showed no distinct sex-ratio effect. The pheromone that was contained within the female helminths as the Kav 0.64 elutant exhibited little variation in its level, based on collection period studies up to 3 hr. However, exposure of females to male worms altered the amount of pheromone at Kav 0.64 that was recovered from maceration and gel filtration of female helminths, presumably owing to pheromone release.</p>