Capture and penetration processes of the free-living juveniles ofTrichostrongylus colubriformis(Nematoda) by the nematophagous fungus,Arthrobotrys oligospora

Abstract

SUMMARYThe nematode-trapping fungusArthrobotrys oligosporatraps and invades all the free-living juvenile stages of the tri-chostrongyle nematodeTrichostrongylus colubriformis. The processes of capture and invasion of the 1st-stage juveniles are described using differential interference contrast optics and 3-D reconstruction techniques. The adhesive responsible for capture is well preserved using a freeze-substitution technique for scanning electron microscopy. The invasion process of the ensheathed 3rd-stage juvenile ofT. colubriformistakes much longer than in the 1st- or 2nd-stage juvenile and involves the formation of secondary infection pegs between the sheath and the cuticle which appear to penetrate the cuticle by physical pressure.