Friday, September 6, 2013

Life in a Log


Bess beetle and larvae, large and small- Click to enlarge
There is lots of life in a dead log.  We occasionally take a rotten log to school groups to let them explore it for all kinds of critters.  Breaking the log apart exposes sow bugs, centipedes, fungi filaments and lots of other critters.  It is a great opportunity to discuss the microhabitat that contributes to life in the woods.

The excitement begins when you roll the log, exposing the creatures which are generally under the log rather than in it.  Moving a log out of the way last weekend exposed a colony of bess beetles nurturing their young.  A centipede disappeared underground in seconds, sow bugs milled around in confusion, and I only caught a glimpse of something long (little snake?  lizard or salamander tail?) darting into the grass.
Bess with a Scarabaeidae larvae*
Note brown mite under head- Click to enlarge









The black bess beetles milled around in confusion, struggling with the decision to crawl under the loose soil or stay with their young.  This isn't just an anthropomorphic fantasy on my part - they really do care for their young. 
"They care for their young by preparing food for them and helping the larvae construct the pupal case. Both adults and larvae must consume adult feces which have been further digested by microflora for a time; an arrangement that might be described as a sort of external rumen."  Wikipedia
Note: two pair of legs








Further, they appear to communicate with each other, producing 14 different sounds.  The adults rub their hind wings against their upper abdomen while the larvae make sounds by rubbing their second and third legs together.   No one has been able to determine what they are saying, but I am betting one of the beetle sounds says "Now eat your feces or you won't grow up to be a big strong beetle," while the grub whines "Aww, do I have to?"

Whenever possible, roll the log back in place, just as you would when looking under a stone.  This is probably home to lots of species and throwing it aside is the microscopic equivalent of running a bulldozer through a woodland.

See these previous blogs on Bess beetles and the mites they carry.
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* Update 21-4-2017
I misidentified this Scarabaeidae larvae on this post originally, thinking it was an early Bess Beetle larvae.  Heather Bird Jackson of University of Tennessee kindly sent me this correction.
"I think it is a Scarabaeidae larvae. It has the distinctive C-shape and it is hard to tell, but it appears to have three pairs of legs (Bess’ have only two pair). I only bring it up because you’ll probably see some more of those scarab larvae and it might be nice to tell the difference. They otherwise look very similar to Passalidae larvae (and are in the same superfamily). "
See these previous blogs on Bess beetles and the mites they carry.

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