Phasmarhabditis hermaphrodita is a facultative parasitic nematode that can kill slugs and snails. It belongs to the family Rhabditidae, the same family as Caenorhabditis elegans.
P. hermaphrodita is a bacterial-feeding nematode and is a lethal parasite of several terrestrial gastropod families such as Arionidae, Milacidae and Limacidae. It is also able to reproduce on rotting matter or penetrate and remain in resistant slug and snail species where it awaits for their death and will then reproduce on the cadaver (necromeny). P. hermaphrodita was first isolated and documented by A. Schneider in 1859 and was intensively studied in the 1990s by researchers at Long Ashton Research centre who were focused on finding a new biocontrol agent for slugs. P. hermaphrodita was isolated here and developed as a biological control agent (Nemaslug®) for minimising agriculture damage from slugs and snails in 1994.
Anatomy
P. hermaphrodita is unsegmented, vermiform, bilateral symmetrical pseudocoelomate. The body dimensions and structure of P. hermaphrodita is comparable to C. elegans''' with a body length 1.3 - 1.7mm long and an estimated circumference of 0.180mm. The primary structures are the Rhabditida-specific mouth, the pharynx, the intestine, the reproductive system (uterus, spermatheca, gonads) and the cuticle. Like all nematodes, it has four muscle bands that span the length of the body and has no devoted respiratory or circulatory system. P. hermaphrodita has four larval stages before becoming a fully reproductive hermaphroditic adult female. Males do exist in this species, but are very rare with Maupas only able to find 21 males among 15,000 individuals (0.14% of the population). Third-stage dauer larvae are produced in unfavourable conditions such as low food levels, high population density or high temperatures. Dauer larvae have constricted pharynx, double the thickness of a normal cuticle and increase of lipid droplets in their cytoplasm. However, the most important aspect of the dauer stage is its ability to serve as the infective stage that seeks out new hosts, once the previous bacterial food source has been depleted.Tan, L., & Grewal, P. S. (2001b). Pathogenicity of Moraxella osloensis, a bacterium associated with the nematode Phasmarhabditis hermaphrodita, to the slug Deroceras reticulatum. Applied and Environmental Microbiology, 67(11), 5010-5016. Dauers do not require a food source and can survive up to eight times longer than the original life span of a non-dauer nematode. P. hermaphrodita is morphologically identical to two other Phasmarhabditis species P. neopapillosa and P. tawfiki. However, P. neopapillosa is a gonochoristic species with an equal number of males and females.
