Steinernema affine (Bovien, 1937) Wouts et al., 1982

Steinernema affine belongs to the entopathogenic nematodes, i.e. they are able to infect and kill insects (see also: Steinernema). It was orginally described as Neoaplectana affinis from Denmark in 1937 and transferred in 1982 by Wouts et al. to the genus Steinernema Travassos, 1927. The pictures show the infective juveniles (i.e. third-stage juveniles), at this stage the mouth and anus are closed and the pharynx is reduced and non-functional. Often the third-stage juveniles are still enclosed by the retained sheath (part of the old culticle) of the second-stage juveniles. The symbiotic bacteria (Xenorhabdus) are enclosed by an intestinal vesicle, just posterior to the basal bulb. So far this species has been found in Europe and North America.

More pictures of Steinernema affine (Bovien, 1937) Wouts et al., 1982:

Steinernema affine infective juveniles: overview
Steinernema affine infective juveniles: overview

Steinernema affine infective juvenile: cuticle finely annulated
Steinernema affine infective juvenile: cuticle finely annulated
Steinernema affine infective juvenile: anterior body with stoma
Steinernema affine infective juvenile: anterior body with stoma
Steinernema affine infective juvenile: anterior body with well developed excretory pore
Steinernema affine infective juvenile: anterior body with well developed excretory pore
Steinernema affine infective juvenile: pharynx region
Steinernema affine infective juvenile: pharynx region
Steinernema affine infective juvenile: pharynx-intestine region with basal bulb
Steinernema affine infective juvenile: pharynx-intestine region with basal bulb
Steinernema affine infective juvenile: intestinal vesicle with symbiotic bacteria
Steinernema affine infective juvenile: intestinal vesicle with symbiotic bacteria

Steinernema affine infective juvenile: nerve ring visible!
Steinernema affine infective juvenile: nerve ring visible!
Steinernema affine infective juvenile: conoid tail with anus and pointed terminus
Steinernema affine infective juvenile: conoid tail with anus and pointed terminus

(Click on the pictures for an enlargement, © Wageningen University & Research, Laboratory of Nematology/Pictures: Hanny van Megen)