Co-Ordination of the Life-Cycle of Contortylenchus Grandicolli (Nematoda: Allantonematidae) With That of Its Host Ips Grandicollis (Scolytidae)

Abstract

Four juvenile stages of Contortylenchus grandicolli were found in the body cavity of the bark beetle, Ips grandicollis. The first moult of the nematode occurred in the egg, two further moults occurred in the body cavity but the fourth moult occurred outside the insect (on agar) to produce males and infective females. Parasitic females from host larvae, pupae and adults had uterine eggs but deposition of eggs occurred only in callow and mature adult beetles. Parasitic female growth and gonad development in larval and pupal hosts did not differ up to 4 days after infection but was greater in pupae 6 days after infection. This coincided with the change from pupae to callow adults and showed significant growth of the parasitic female in the callow adult prior to nematode egg deposition. Functioning of the reproductive system of the nematode (in terms of egg deposition) was inhibited in larval and pupal hosts.