WAR  of  the  MICROWORLDS  

How do I kill Thee?   Let me count the Ways!   (# 28)  click here for full list

(Images from Mycoalbum CD)

Rhopalomyces elegans: The spores of Rhopalomyces are very large, dark brown, and are produced on a swollen vesicle at the tip of a tall stout 'conidiophore'.   The hyphae extremely fine (circa 2 microns wide).   The large spores germinate in the presence of nematodes (in response to a signal chemical) and have sufficient reserves to produce an extensive mycelial network in the environment.   Fine hyphae of the fungus will seek out a nematode egg and bond to the 'shell' using a swollen appressorium.  The fungus pushes against this anchor to penetrate the egg and produces a  post infection bulb from which large diameter assimilative hyphae arise to fill the egg and digest and absorb the contents.   A feature of particular significance in Rhopalomyces and probably other members of the Helicocephalidaceae is the ability to prode vegetative hyphal anastomoses, a rare accomplishment in the Zygomycota.   I have seen anastomoses in the vegetative hyphae of Rhopalomyces elegans and observed continuous protoplasmic flow across the hyphal bridge.  Rhopalomyce magnus is similar to R.elegans but attacks rotifer eggsZYGOMYCOTAFor further information on Rhopalomyces check  Barron, G.L. 1973. Nematophagous Fungi: Rhopalomyces elegans. Can. J. Bot. 51: 2505-2507 and Barron, G.L. 1980. The biological role of Rhopalomyces magnus. Mycologia 72: 427-430.

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 TOP RIGHT AND BOTTOM LEFT: Rhopalomyces elegans attacks nematodes and nematode eggs.   BOTTOM RIGHT: Rhopalomyces magnus attacks rotifer eggs.  So far as we know the entire raison d'etre of Rhopalomyces species is to parasitize eggs of microfauna and they appear to be phylum specific i.e. Nematoda for R. elegans and Rotifera for R. magnus but, in truth, little is known about the breadth of their attack capabilities against eggs of other microfauna.