A winged Asian subterranean termite alate is surrounded by three adult Asian subterranean termite soldiers. PHOTO: DR. RUDOLF SCHEFFRAHN
In 1996, a “new” subterranean termite was found in Miami, Fla. Earlier in 2023, it was discovered about 280 miles north in Tampa, Fla. While it is doubtful these termites will ever migrate out of the Sunshine State, it’s not a 100 percent safe bet.
Commonly referred to as the Asian subterranean termite — and for a short period known as C. havilandi before it reverted to its original taxonomy — this species is considered to have as much potential for damaging structures as the Formosan subterranean termite (C. formosanus). It is endemic to Southeast Asia, although the oldest report of the species dates to Brazil in 1923.
The University of Florida bulletin on the species, as written by Dr. Rudolf Scheffrahn and Pest Management Professional Hall of Famer Dr. Nan-Yao Su (Class of 2018), points out that soldiers of both species look similar, with a large opening on the forehead called the fontanelle.
According to the bulletin: “When viewed from above, both also share teardrop-shaped heads. Microscopic examination of the fine hairs on the head reveals diagnostic differences: C. gestroi soldiers have one pair of hairs near the rim of the fontanelle, while in C. formosanus, two pairs originate around the fontanelle. Additionally, the lateral profile of the top of the head just behind the fontanelle shows a weak bulge in C. gestroi that is absent in C. formosanus.”
Soldiers of both species, per the bulletin, comprise up to 15 percent of foraging groups, “aggressively bite when challenged, and exude a white mucous-like secretion from the fontanelle.”
Differences among the two species’ alate populations are more noticeable, the bulletin says:
“C. gestroi are slightly smaller than those of C. formosanus (total length with wings about 13 to 14 millimeters vs. 14 to 15 millimeters, and maximum head width of 1.4 millimeters vs. 1.5 millimeters, respectively). The head, pronotum, and dorsal abdomen of C. gestroi alates are dark brown, while those of C. formosanus are entirely a lighter yellow-brown or orange-brown. The darker pigmentation of the C. gestroi head provides a contrasting background for two light patches on the face called antennal spots. In C. formosanus, the antennal spots are barely visible, if at all. The length of wing hairs is somewhat shorter in C. gestroi than in C. formosanus.”
One way these ravenous termites might travel north sooner than later is through a hybrid subterranean species, the result of mating among C. gestroi and C. formosanus termites. Research continues at the University of Florida to see whether that is a viable (and thus volatile) option. According to a 2022 article from the University of Florida, “South Florida is one of three places on Earth (the other two being Taiwan and Hawaii) where both species exist in the same place, and the situation has led to interbreeding between the termites.”
REFERENCES
- “AskIFAS,” accessed April 4, 2023: EDIS.ifas.ufl.edu/publication/IN285
- “FORMOSAN SUBTERRANEAN TERMITE,” accessed April 4, 2023: Bugs.ufl.edu/bug-pix/formosan-subterranean-termite
- Truman’s Scientific Guide to Pest Management Operations, Seventh Edition, available for purchase at MyPMP.net/shop
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