Rev 05/10/2024
Type species of the genus: Neosteinernema longicurvicauda Nguyen & Smart, 1994
Generally simiolar to Steinernema
Labial region with 6 labial and 4 cephalic papillae
Tail conoid with digital terminus; conspicuous phasmids. longer than abd
Female:
Didelphic amphidelphic
Ovoviparous
Male:
Spicules foot-shaped with dorsal swelling
gubernaculum almost as long as spicule
Single midventral genital papilla anterior to cloaca, 8 pairs of precloacal and 6-7 pairs postcloacal
In the dauer stage of the infective juveniles (IJs) in the soil, Xenorhabdus spp. are carried in a specialized region of the intestine.
The IJs invade the hemocoel of susceptible insect hosts. Bacteria are released in the insect hemocoel, where they overcome the insect's defense systems and produce numerous virulence factors such as hemolysin and cytotoxin. The insect host is killed.
The bacteria proliferate to high levels in the insect cadaver and produce diverse antimicrobial compounds that suppress the growth of antagonistic microorganisms. Xenorhabdus spp. also secrete an array of exoenzymes that stimulate macromolecular degradation.
Nematodes feed on the proliferating bacteria
Like species of Steinernema, and unlike species of Heterorhabditis, the first generation of adults developing from the IJs are amphimicitic, not hermaproditic; they reproduce sexually. Subsequent generations of adults are also amphimictic.
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