They exit the host in the thousands? They have a newly acquired taste for humans? Anyone else find this interesting?
Scientific Article
http://www.benthamscience.com/open/totnj/articles/V003/SI0082TOTNJ/101TOTNJ.pdf
"Simplistically, the IJ
nematodes actively seek out their prey, usually insect larvae
within the soil. Upon finding a suitable host, the nematode
physically penetrates the insect and migrates to the
hemocoel. Here the bacteria, residing in the gut of the IJ, are
transferred directly into the hemocoel where they are able to
evade the insect’s immune response and kill the insect using
a variety of toxic mechanisms, before reducing its carcass to
a nutrient soup. The bacteria feed off this soup and the
nematodes then feed off the bacteria. During this time the
nematodes undergo one to three rounds of sexua| replication
until food supplies become low, whereupon bacteria
recolonise the nematode progeny and these new infective
juveniles and their respective symbiotic bacteria emerge
from the host in their thousands.
Interestingly P. asymbiotica is also pathogenic
to humans and was first identified from human clinical
isolates in the USA and Australia [9, 10]. This too is likely to
be a reproductive dead-end for the symbiotic H. gerrardi-P.
asymbiotica complex [11, 12]. Studies are currently ongoing
to determine the divergence of P. asymbiotica from the other
Photorhabdus ssp. by comparative genomics of P.
asymbiotica and P. luminescens strains (Wilkinson P.,
personal communication). Also of great interest are the
changes in trophism of the H. gerrardi nematode and its
newly acquired taste for human prey."
"Here the nematodes
release their bacterial payload and begin to mature in
response to an as yet unidentified signal which appears to be
related to feeding. In S. carpocapsae it has been
demonstrated that the ingestion of hemolymph triggers the
release of Xenorhabdus [15]." (ROD SHAPED NON-FLORESCENT SELF REPLICATING BACTERIA. COULD THIS BE THE BLACK RODS WE SEE?)
"Photorhabdus (SELF REPLICATING FLORESCENT BACTERIA... HMMMM. INTERSTING) are egested
through the mouthparts [16] whilst Xenorhabdus are actively
released through the nematode anus. Once released the
bacteria are recognised by the insect immune system and
have had to evolve a variety of methods of evading specific
immune responses within the insect."