Social insects such as ants and termites have changed many of the rules on how scientists understand biology. For centuries, that has led researchers to ask how such organisms could have evolved to be so successful.
However, a team of University of Florida entomologists in Fort Lauderdale finally provides a first-time look inside the remarkably long life span of several Formosan subterranean termite colonies.
UF/IFAS scientists learned that each termite colony may attempt different strategies to optimize their chances of survival and reproductive success.
“Scientists have often observed ant and termite colonies during short periods of time to study fascinating behaviors from these complex social animals,” said Thomas Chouvenc, an assistant professor of urban entomology at the UF/IFAS Fort Lauderdale Research and Education Center (FLREC). “However, no one was able to follow the demographic history of a whole colony through its entire life, which can last decades.”
In an unprecedented effort initiated in 1986 by UF/IFAS Distinguished Professor Nan-Yao Su, also in Fort Lauderdale, scientists monitored colonies of the Formosan subterranean termites in the field on a monthly basis, until 2009 when the project was stopped.
“The outcome of this effort resulted in a treasure trove of information, revealing unknown aspects of a termite colony’s complex biology, and it provided unique explanations on why some subterranean termite species can be so good at being problematic pests to buildings,” Chouvenc said.
“With more than 15,000 data points and a dozen of different variables from many colonies collected over decades, it took us dozens of independent studies and more than an additional decade to analyze this dataset and make sense out of it,” Chouvenc said.
For the first time, the researchers observed the changes in the population structure within four independent termite colonies over a period ranging from 10 to 24 years of monitoring. Scientists revealed that a mature termite colony can seasonally produce thousands of alates, the winged termites that fly away to make new colonies, every year and for several decades.
“We initially thought that all four colonies would be following similar demographic and reproductive patterns. However, each colony had a unique profile, to the point that we concluded each colony can display a unique demographic individuality” Chouvenc said.
The UF/IFAS researchers also found that colonies may lose their initial primary king and/or queen but can produce many secondary reproductive queens and kings to maintain reproductive output through long inbreeding cycles.
“What was fascinating about these findings is that some colonies failed to produce replacement queens and kings, and died after a three-year period of colony senescence,” Chouvenc said “On the opposite side, some colonies were able to produce more than 1,300 replacement queens and kings and continue thriving for more than a decade.”
In fact, this dataset revealed that each colony demographic trajectory is unique through their perennity, he said.
“Now that we know how complex and diverse this is, we can now take this information into account for the implementation of future pest control solutions.” Chouvenc noted. The study, published in Frontiers in Ecology and Evolution, showed that a mature Formosan termite colony has many options and strategies to optimize its reproductive output, and can switch from one strategy to another over the decades to survive.
Chouvenc also likened the finding to the changes that happen in a big city over time, such as the changes in demographic composition, building architecture, economic productivity over a 75- to-100-year history.
“In termites, it’s similar but at a different scale where the colony goes through a generational turnover every three to four years. A colony demographic outcome changes because of shifts in reproductive strategies, physiological flexibilities and environmental changes,” noted Chouvenc. “In a way, just like our cities, termite colonies are resilient and change over generations. So as each city is unique, each termite colony is just as unique,” concluded Chouvenc.