Chemoattraction inPellioditis pellio (Nematoda: Secernentia) in the presence and absence of barriers.

Pellioditis pellio (Nematoda) adults showed heterosexual chemoattraction and female homosexual chemoattraction in an in vitro bioassay without barriers. Male-to-female heterosexual, but no homosexual chemoattraction, was observed whenM r 25,000 pore size dialysis tube chimneys (barriers) were used to restrain female attractor worms. Less attraction was seen whenM r 12,000 pore size barriers were used. The results suggest the presence of at least two types of chemoattractant for this species and that at least one heterosexual chemoattractant is betweenM r 12,000 and 25,000.