Two of the most destructive species of invasive termites are joining forces in Florida. By mating together, they're forming prolific hybrid colonies. Scientists are now worried about the potential damage these insects will inflict on Florida's dwellings.

In total, entomologists have catalogued over 2,800 termite species, but only 6% of are classified as pests to human structures. It's estimated that termites cause upwards of $40 billion in damage each year.

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Among the most notorious termite pests are China's Formosan subterranean termites (Coptotermes formosanus) and the tropical Asian subterranean termites (Coptotermes gestroi). Both of these species have been introduced to Taiwan, Hawaii, and south Florida on account of human activity. These bugs hail from the same genus, Coptotermes, but they evolved separately and haven't interacted for thousands of years. However, despite evolving in separate ecological niches, these termites have retained the ability to interbreed.

Hybridization among native species is a common occurrence, but interbreeding between two invaders is rare. University of Florida at Fort Lauderdale entomologist Thomas Chouvenc and his colleagues are now extremely worried about the synergistic effects produced by the intermingling of these two foreign species.

Termites are similar to bees and ants in that they're social insects. Their colonies consist of queens and kings, who are in charge of reproduction; workers, who supply everyone with food and maintain the nest; and soldiers, who protect the colony. Scientists thought that the two species had distinct swarming seasons — the time of year when alates establish new colonies. Shockingly, however, C. formosanus and C. gestroi now appear to have overlapping swarming seasons. This overlap means that the two most destructive termites in the world now have the opportunity to interbreed.

Compounding the problem is the observation that the Asian termite males prefer to breed with Formosan females. This is increasing the risk of hybridization.

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This worries the researchers who say the combination of genes results in highly vigorous hybridized colonies that can develop twice as fast as the two parental species.

The new hybrid colonies are expected to inflict serious damage to south Florida homes and businesses in the near future. The researchers also worry that the hybrids could eventually make their way out of Florida.

The researchers don't know if a hybrid colony can produce fertile and fully functional alates for maintaining future hybrid colonies. Because of their long life cycle, it could take 5 to 8 years before colonies mature in the lab and in the field. Further work will be required.

That said, and in the words of the researchers:

Coptotermes mature colonies can contain millions of individuals and live up to 20 yrs and even in the absence of alate hybrid fertility, the persistence of hybrid colonies in urban environments would still present a threat to structures.

In other words, "a kick from a mule is as good as a kick from a donkey."

Read the entire study at PLoS One: "Hybridization of Two Major Termite Invaders as a Consequence of Human Activity".

Images: Chouvenc et al.

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