Niche overlap among three species of pinworm parasitic in the hindgut of the American cockroach, Periplaneta americana.

Individual American cockroaches, Periplaneta americana, often harbor 3 species of pinworm (Oxyurida: Nematoda) Thelastoma bulhoesi, Leidynema appendiculatum, and Hammerschmidtiella diesingi, simultaneously. We looked for evidence of trophic niche segregation based on differences in size preference among the 3 species. Fluorescent beads of 1, 3, 6, and 10 microm diameter were mixed in agar and fed to individual hosts. Adult female worms of each species were removed from hosts, and the number of each size of bead in each worm was assessed. Horn's R0 and Hurlbert's L indices of niche overlap were calculated for infracommunities containing at least 1 of each species. Hurlbert's index extends the information given by Horn's index to include the effects of proportional availability of each resource. Both indices indicated a lack of trophic segregation based on particle size among the 3 species. Species did, however, differ in consumption rate: L. appendiculatum ate more than T. bulhoesi, which ate more than H. diesingi.