Microworms

Panagrellus redivivus (sour paste nematode)

synonym Panagrellus silusiae (beer nematode)

P. redivivus is a small, free-living (an organism that does not need an intermediate host as in parasites) nematode found in soil. It is closely related to C. elegans, an organism which also frequently studied in science. 

Literature places some confusion on the biology of the organism. Some claim that the nematode is a “self-fertilizing hermaphrodite” with occasional male. Other sources state that reproduction is sexual with no mention of the hermaphroditic tendency. However when speaking of the sexual reproduction and male/female traits, mention of males being “less numerous than the females” may be a significant observation within the context of the first (hermaphrodite) statement. However, the source making the claim of self-fertilization is siteing information from the Riddle Lab, and that information is referring to C. elegans and not P. redivivus. 

Like other small nematodes (as in “vinegar eels” or Tubatrix aceti), the males have a curved tail and are generally smaller than the females. P. redivivus do not lay eggs and are livebearing. They reproduce very quickly, females birthing up to 40 babies every one or two days for most of their life span.  

P. redivivus  live for several weeks, but not more than a month. They grow quickly to maturity (about 3 days) and reach a maximum size (0.45 – 2 mm) in just six days.

There are references that indicate that perhaps the nematodes are somewhat sensitive to light, but generally speaking they are not overly sensitive to stimuli. They move by wiggling in a “snake-like” fashion. These nematodes consist mostly of their reproductive system, a couple of nerve cords and several small muscle groups. They are what one might refer to as “simple.” 

Commonly referred to as “microworms” in the tropical fish hobby, these nematodes have been cultured by aquarium hobbyists since the 1930s. They can used as a substitute for newly hatched brine shrimp (artemia nauplii). As the price of brine shrimp eggs rises and falls on the world market of edible shrimp production, microworms decline and rise in popularity. 

From time-to-time, aquarium hobbyists debate the nutritional value of microworms. Jokes are frequently made that the nutritional value of microworms increases with the increase of the price of brine shrimp cysts.

Other literature, while providing nutritional content information about microworms (48% protein, 21% lipids, 7% glycogen, 1% organic acids, and 1% nucleic acids), do not support the information with references. In a paper for the Journal of World Aquaculture Society, Ricci, Fifi, Ragni, Schlechtriem and Focken  state, “The nutritional value of P. redivivus is high and comparable to that of Artemia.” (dt/ba)

(source : http://www.livefoodcultures.com)