Missouri Master Naturalists- Springfield Plateau Chapter

Friday, December 13, 2019

Fungus Beetle


Anyone who has hiked a few of our Ozark forests has likely seen these bracket fungi growing like shelves on dead or living trees.  They are called Trametes aesuli now, but the books still call them Trametes elegansThey are tough, leathery and hard to break off the tree.  These are hardened members of the polypore group of fungi.  We collect them for WOLF School students to paint on.

This is a great example of nature's recycling.  Trametes fungus species grow on trees which have some dead tissue, a process called sap rotFungi send enzymes out of their fine hyphal threads to break down the wood and digest the cellulose, a hard trick for anything that has legs.  Even termites depend on microorganisms in their gut to grind the cellulose into something they can turn into energy.  The hard fruiting bodies of these polypores have nutrition that few legged creatures can use.  This is where fungus beetles enter the picture.  These species are obligate fungivores (fungus-eaters), meaning that their specialized digestive systems can only digest fungi.  A prime example are the Neomida bicornis below.
Neomida bicornis found in bracket fungi - REK
I was recently surprised to discover that T. elegans is the main course in the diet of Neomida bicornis.  I stored several hard dried fungi in a sealed plastic bag for future artists and when I opened it six months later they were riddled with holes.  In the bottom of the bag there was lots of powder as well as over 100 little black dots.  On closer inspection they were fungus beetles that had eaten their fill before dying of dehydration and old age.

 

The WOLF School students made another discovery while examining the beetles under the microscope, a beetle larva that had been hidden in the frass.  It has been dried for months and I can only find these photographs of the larva in their living state, so I can only assume that it is also N. bicornis.

Neomida bicornis - REK
Neomida  are strictly fungivorous (fungi-eating) beetles of the Tenebrionidae family.  They bore into the hard conks of Polyporales hosts.  Zookeys states that there are approximately 50 species of Neomida beetles world wide.  For anything that is science you can find experts immersed in the chase. Here are some of their identifying features:
"Members of Neomida are diagnosed by the following features (taken from Triplehorn 1965): antennal club loose and with seven antennomeres; eyes emarginate anteriorly close to antennal insertions, forming a lower portion at least twice as long as the upper portion; head of males usually bearing horns or tubercles on frons or clypeus, or both; prosternal process convex; elytral punctation seriate; basal tarsomere of hind tarsi short." Zookeys
  Katja Schulz
The Neomida bicornis are cute by any 5th grade WOLF School definitionBicornis means (two-horns), referring to the male's head decoration.  Only they know what purpose they serve.  In the deep south they sport an orange pronotum, a trait that disappears as they are found further north.  The beetles are a metallic blue-green in life but our specimens are contracted by dehydration with their pigment broken down with age.  Left in nature they too would be recycled by bacteria and fungus, just like we all are, completing the circle of life.
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Even tiny 3mm beetles can carry smaller mites.  See this photo by Tom Murray!