If anyone either works in a biology lab or remembers the classic high  
school experiment where a nutrient rich media is exposed to the air  
for a brief time and incubated you will realize--we are not alone!

Fungi are everywhere!  This is hugely diverse group including  
toadstools, yeasts & mold--and now DNA techniques are providing  
insight such that nosema  formerly a spore forming protozoan should  
more likely be classified as a fungus as well.  Not a big surprise to  
some.

I work in a group that studies fungal pathogens of insects  
(entomopathogens) .  Down the hall is the ARSEF culture collection  
with 8000 entomopathogens in liquid nitrogen.  This is the largest  
collection of insect pathogenic fungi in the world.  The collection  
consists of fungi thought to kill insects.   At least most are  
thought to kill insects.  Some fungi do kill, some are weakly  
infectious and others may only grow on recently dead (or dying)  
insects.  Much of the fine details on many, many collected species  
are really unknown & untested.

Two insect pathogens, Beauveria bassiana (Bb) and Metarhizium  
anisoplia (Ma), are very common soil inhabitants and can be found  
almost everywhere.  There are commercial products made from these  
fungi so that they can be sprayed much like any insecticide.  The  
formulation of fungi as insecticides  are commonly called  
mycoinsecticides.  Note that there are many other species in the  
genus of Beauveria and Metarhizium.  It is mind boggling the numbers  
& niches that fungi inhabit.

Other fungi in these genus are also found in soil, under bark, in  
detritus, and really anywhere there is nitrogen & starch (or sugar),  
as well as other hyphomycete fungi; think bread mold & mildew.  These  
are common contaminants as you are probably aware.  There is  
competition among fungi for nutrients and many fungi have evolved the  
secretion of secondary metabolites that inhibit other species so that  
the first colony on a newly found nutrient source gets first dibs,  
that is part of the colors & clonal patching that you often see in  
moldy areas.

Fungus is everywhere; the smell of those old ABJ magazines stored in  
the cellar (where it is a little moist) is due to the growth of mold.
Probably this is not the spot to ask if anyone would sell me their  
ABJ issues from July 04-Feb 05--But I'll ask anyhow as I'm trying to  
complete all of George Ayers articles on honey plants & missed those  
issues.

Anyhow with the above background you can see that if you stick a  
highly nutritive media in a colony of bees, add cool damp conditions  
and you will see mold.  There is mold spores on the bottom board on  
old comb etc which can get started particularly when colonies are  
weak, wet or cannot cover everything.

It always amazes me to see how little does grow given the amount of  
spores in the environment.  I think the only reason that more does  
not grow on pollen patties is that the bees consume it first.  I know  
I find lots of fungus in an insects alimentary tract. I bet cultures  
grown from pollen patties of various age would have an enormous  
number of species if care was given to separate out the competing  
strains.

I recently read an abstract somewhere on the honeybee genome project   
that looked at the genes usually responsible for insect immune system  
development/action.  The number was found to be greatly reduced.   
They hypothesized that perhaps this was why honeybees were reliant on  
propolis as an extension to a minimalist immune system.  It will be  
interesting to see what else comes from the genome project.

So to conclude this ramble--there are a huge number of fungi, the  
soil is a reservoir, some can actively infect insects, others infect  
only weakened or diseased insects, and some utilize the nutrients in  
dead insects.  Many of these fungi are present everywhere awaiting  
the opportunity to exploit a nutrient source when conditions of  
appropriate moisture  and temperature are reached.

It is amazing how little fungus that we see in our hives considering!

Mike Griggs

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