A Virbacaphid?

Bacteriophages encode factors required for protection in a symbiotic mutualism.
http://www.ncbi.nlm.nih.gov/pubmed/19696350

A Virbacaphid?
... not to be confused with a Turducken - the subject of today's post is about a three-tiered symbiotic relationship in the insect world.

[Apologies for the long layoff since the last post - this writer got married, started a new project in the lab, and generally bit off too much to chew].

The process of symbiosis is one of biology's most central and yet in some ways most inexplicable phenomena. Symbiosis refers to a situation in which two initially independent organisms, of (often vastly) different species, work together to benefit each other. A classic example of this is our own intestinal tract, where friendly bacteria help us digest and absorb nutrients from food which would otherwise hold no nutritional value. Another well-known example is the small birds in Africa (tickbirds) who clean flies and other insect larvae from the skin of rhinoceri (if that isn't the plural, it should be). Perhaps the most-popularized of all, thanks to the recent Disney movie, is the relationship between the clownfish and the sea anemone, in which the anemone's stinging tentacles protect the clownfish from large predators, while the clownfish prevents small predators from eating away at the anemone. Symbiosis may begin as a simple mutual benefit, but some symbiotic relationships have progressed so far (coral and algae for example), such that one or both organisms cannot live without its symbiote.

Symbiotic relationships are prevalent and varied throughout nature, and most larger organisms are involved in some mutually beneficial relationship with another species. Another common but perhaps not as widely publicized symbiotic relationship occurs between pathogenic bacteria and viruses that infect them, also known as bacteriophages. These 'phages can provide pathogenic particles akin to poisons or venom that the bacteria use for defense, or attack. Today's story involves a truly amazing symbiosis. The aphid, a type of leaf-grazing insect, is susceptible to attack and parasitism by a type of wasp, which lays its larvae on an aphid; when the larvae hatch, the fledgling wasps consume their host. However, through symbiosis, the aphid has a defense mechanism. The aphid has formed a symbiotic relationship with a type of pathogenic bacterium that has itself formed a symbiotic relationship with a bacteriophage virus. The 'phase produces a poison that the bacterium secretes, and this poison kills the wasp larvae attacking the host aphid.

Just picture a virus riding on a bacterium riding on an aphid. Quite an entertaining picture, no?
- ps