Wednesday, August 27, 2014

Bumelia Borer

The star of this year's Insectorama at the Springfield Conservation Nature Center was undoubtedly the bumelia borer, a magnificent longhorn beetle found by Kim Banner in her garden.  Almost everyone had never seen one before, an insect you would be unlikely to forget.

Adult beetle, green color form - Photograph by Ted C. MacRae
While common names of insects can be confusing, it is unlikely that many of us will use the bumelia borer's official title, Plinthocoelium suaveolens suaveolens.  (Say that 10 times and you will still forget it.)  It has several color forms ranging from bright blue through irridescent green to bronze.  Its femora are consistently reddish-orange with black tibia.  At 1.5 inches in length, it is hard to miss.

Larva of Bumelia borer - Photograph by Ted C. MacRae
Its larvae develop in the trunks and roots of gum bumelia, water tupelo and mulberry.  In Missouri it has been associated with gum bumelia, (aka gum bully or woolly buckthorn), a plant adapted to xeric (dry) glades typical of southwest Missouri.  The adults are active from May through summer where they feed on the sap of host plants and hickory.

Rhea Blackthorne
Sandra McKennon-Volk

Dr. Tom Riley shared this additional information:
" Males will sit head-down at the base of the trees, waiting for females to emerge. They also come to the flowers. In a good year they can be quite abundant with 5-6 beetles on each flowering tree. Once you take a swing at them they put out a really low vapor-pressure alarm pheromone and suddenly, like in the rest of the genus, all the beetles in the area disappear. The beetles either live or continue to emerge for a long time. We collected them from July until October."
"Make my day!"  Head on photograph by Dr. Tom Riley
They are found across the southern U.S. from Florida and Georgia west to New Mexico and Arizona.  None of us had ever seen this creature of the glades and it was a lucky find especially in an urban garden.  A good idea of how hard these are to find when you are searching for them is documented in this long Beetles in the Bush post.  There are several lessons for us neophytes.
  1. You have to know your host plants, looking at every one to find a specimen... maybe.
  2. When you find a specimen, catch it in case you don't find another one.  The second one you can try to photograph in the wild.
  3. Sometimes you have to kiss a lot of frogs to find a prince.
Beetles in the Bush has dramatic closeup pictures and information on how he gets his pictures.