Master Naturalists: 2011 season for trapping exotic, invasive beetles ends
By Paul and Mary Meredith
As in 2010, Mid-Coast Chapter Texas Master Naturalists participated in the 2011 U.S. Forest Service Early Detection and Rapid Response Survey project to trap and identify destructive beetles introduced into Texas via shipping entering our ports. Mary and Paul used a small grove of trees located on the point between the Point Comfort Turning Basin and the Alcoa docks at Alcoaâs Point Comfort Operations. This location is on Calhoun Port Authority land, and the trapping was done in cooperation with the port and Alcoa.
Last year, volunteers at 10 Texas locations trapped more than 4,200 non-native beetles in 43 species. This year, volunteers at only nine locations trapped 1,767 beetles in 41 species. Anthony Cognato, a Michigan State University entomologist, classified and identified the beetles. That adds up to a lot of time on a microscope because most of the critters are no larger than a medium-sized rice grain.
HOW DID WE DO AT POINT COMFORT?
Our trapping program used three funnel traps, each with a different pheromone lure to attract the beetles. We trapped 41 exotic beetles in several species of Hypothenemus; and one exotic Xyleborinus saxesenii, a first for Point Comfort. Last year, we had 24 Hypothenemus in three different species. All are native to Asia or Southeast Asian islands. We got lots of domestic beetles as well: various metallic wood borers, Longhorn beetles, Soldier beetles; and, of course, some June bugs wandered in as well. All the domestics were larger than the foreign exotics. But the exotics, though small (2-5 mm long), are potentially more destructive because they have few natural predators here.
DID THE PROGRAM SHOW THINGS ARE BETTER OR WORSE?
The catches in 2011 showed mixed results. Our trapping program found almost twice as many beetles as in 2010, with one new species. Statewide, fewer exotics were trapped and two fewer species were positively identified; thatâs good. But, we had fewer trapping locations operating. Moreover, on June 29, trappers working Sheldon Lake State Park (NE Harris County) found Xyleborinus artestriatus, commonly called a Scolytinae bark beetle, an entirely new species for Texas. They just missed a national first; the same species was first found in Georgia on April 15. Itâs from New Guinea and itâs nasty because it preys on several introduced trees like Ficus, English Walnut, Mangos, and Monkey Puzzle. Those kinds of records and firsts are not good for Texasâ commerce or its forests.
So far, as we know, no major trapping programs involving saturation trapping of an area have been implemented to prevent a runaway invasion. However, that might be necessary if any of these species escape the port areas and start reproducing rapidly. Thatâs part two of EDRR, a rapid response to control an exotic before it becomes a big problem. Next yearâs data will tell us more about population trends and the effects of the stateâs extreme weather conditions on speciesâ spread. Our recent cold winters will help reduce populations of these tropical species, but the drought may help them because trees under stress are more likely to develop infestations. We continue hoping for a break in the drought, but the prospects donât look good, according to climatologists who know a lot more than we do.
Paul and Mary Meredith are master naturalists. Contact them at email@example.com.