what’s that bug? is it benefitial?
January 19, 2010
I was sawing a bush that is called here (in Hawaii) Holy Coa. suddenly these bugs apeared out of nowhere. Here are 2 photos of them.
Kauai Hawaii USA
We thought your beetle bore an uncanny resemblance to the Mesquite Borer, Placosternus difficilis, a species BugGuide reports from Texas and the “Southern tier of U.S. states, south to Honduras; Cuba, Bahamas.” We then did a web search to see if the Mesquite Borer was introduced to Hawaii, and we were immediately led to another BugGuide page of an insect found in Hawaii and placed in the same genus, but with the disclaimer: “Placosternus crinicornis (Chevrolat) has been recorded from Hawaii but not P. difficilis.” We followed that thread and were led to the Insects of Hawaii page on Placosternus crinicornis, the Kiawe or Prosopis Round Headed Borer which is listed as non-native. It may also be found on an Invasive Species website. According to Wikipedia, Kiawe or Prosopis limensis is a species of mesquite native to South America. Since neither the insect nor its host are native to Hawaii, it is fair to say that neither are beneficial to helping to maintain the indigenous biodiversity of Kauai.