Question

What are the key characteristics of microbial endosymbionts of insects?

Answer 1

Endosymbiotic relation between insects and some bacterias are either facultative or obligate. The bacteria lives intracellularly in insects which change them in the course of evolution as they have to change their physiology to adapt and accomodate the guest.

Most ot the endo symbionts involved in this is gamma proteobacteria, a close species of E.coli.

The main characters of endosymbionts are,

1) They are located intracellularly in the host cell.
2) Prokaryote is literally
sequestered within a eukaryotic cell and cannot be
cultured on common laboratory media.
3) 15-20% of all insects are having this endosymbiotic relation with bacteria.
4) This symbiotic relation has a history of 300 million years.
5) The bacteria offer nutrient enrichment to insects.
6) Insect endosymbionts
live in a very close environment, inside specialized host
cells called bacteriocytes, which may form an organ-like
structure (bacteriome) in the body cavity of the insects.

7) The association is obligate for both partners: the bacteria
cannot be cultured outside the host, whereas the host
needs the bacteria for normal growth and reproduction.
8) Bacteriocyte-associated endosymbionts of insects are
vertically transmitted from the mother to the offspring.
9) Antibiotic and heat treatments in insects which killed intracellular bacteria, had less longevity.
10) The insects genome is related to the bacterial one due to long years of history. The insects prone to have this relation are the ones having less nutrient capturing efficiency which is overcome by sumbionts.