The two most destructive termite species in the world have found their way to Florida and are now pairing off with one another, raising fears that colonies of a new “super” hybrid could soon be on the way. And if lab studies represent what’s going on in the field, then this could be pretty bad news: the resulting hybrid colonies grew twice as fast as those of the parent species and could potentially have a wider range, meaning they could go on to invade new habitats. The findings have been published in PLOS ONE.
Human activities, such as habitat alteration or transport, can facilitate the spread of a species to a new area, but this tends to favor those with invasive capabilities since these species are able to easily adapt to their novel niche. While it’s well-known that these invaders can cross-breed with native species, it’s very rare for two invasive species to hybridize, but now it seems we may have another case on our hands.
The Formosan subterranean termite (Coptotermes formosanus) and the Asian subterranean termite (C. gestroi) are extremely destructive urban pests responsible for a substantial chunk of the $40 billion damage caused by termites each year. The former comes from China and Taiwan, whereas the latter is native to south-east Asia. But thanks to human activity, both species have spread to and established themselves new areas, and there are now three places where their distributions overlap: south Taiwan, Hawaii and southeast Florida.
In south Florida, scientists had documented that the two species have distinct mating seasons in which the colonies release thousands of individuals that swarm, drop their wings, find a mate and then establish a new colony. But this time two years ago, scientists observed for the first time both species dispersing in a single location, providing the opportunity for interspecies mating.
Worryingly, field studies then revealed not only that the two species were indeed pairing off, but also that C. gestroi males preferred to mate with C. formosanus females. Although it’s not clear why at this stage, lead author Thomas Chouvenc told Live Science it’s possible that both species may use the same mating pheromone, but female Formosans could be emitting slightly more than the female Asian termites.
To investigate the potential consequences of species hybridization, researchers from the University of Florida collected males and females from both species and brought them into the lab. While colony establishment rate was found to be the same for the different pairings, alarmingly, the hybrid colonies grew twice as fast as normal colonies, producing around 150 termites per year compared with only 80 for single-species colonies.
Of course, this does not necessarily represent what is going on in the field, but the researchers have further studies planned. Furthermore, at this stage it is unclear as to whether the hybrids will be fertile or sterile, like mules. But even if the hybrids cannot reproduce, the researchers point out that they still represent a potential threat to buildings given the fact that colonies can survive up to 20 years.
