Pseudothysanoes multispinatus. Photo by You Li.
Dr. Andrew Johnson of the Hulcr Lab at the University of Florida has finally found his white whale. After years of looking for Psuedothysanoes multispinatus, a bark beetle last observed by any scientist in 1974, Johnson finally found some while looking for ripe loquat fruit on the UF campus.
P. multispinatus is a member of the micracidini. Like many of the clade, it typically feeds on drier material than most bark and ambrosia beetles. This species is exclusive to basswood, at least among the three occasions to date on which it has has been observed.
The first known specimens, gathered in the 1930’s, reside in the Smithsonian’s Museum of Natural History while the ones from the 1970’s are in the Florida State Collection at DPI. The seven beetles already prepared by Johnson will be added to UF’s substantial collection of bark and ambrosia beetles.
But there may be more. A twig of basswood sits in a covered jar on Johnson’s desk. Rows of tiny holes line the bark.
Johnson says that these beetles always form a single hole per gallery. Each gallery contains two adult females and a single male with spikes covering its back, who usually blocks the entrance. About twenty beetles are likely still living and feeding inside of the twig. Johnson hopes to capture more samples as they mature and emerge, and possibly breed an additional generation.