(07/08/20) BATON ROUGE, La. — Many insects, such as ants, bees, wasps and termites, live in cooperative groups with one or a few reproductives and many workers. And reproductive conflicts are common in these insect societies, said Qian “Karen” Sun, an assistant professor in the LSU AgCenter Department of Entomology.
A typical termite colony starts with one queen and one king. A queen can live for 30 to 40 years while most workers live for one year. Eventually, however, the queen or king dies, and some immature termites, such as workers, start to differentiate into replacement reproductives.
As reproductives emerge, competition begins.
“One of the mechanisms regulating these conflicts is ‘policing,’ a coercive behavior that reduces direct reproduction by other individuals,” Sun said.
Policing by members of the colony allows termites to regulate reproductive division of labor, according to a recent peer-reviewed paper published in the Proceedings of the Royal Society B, Biological Sciences that can be found online at https://bit.ly/2ZWioiu.
Sun, the lead author of the paper, said the term policing among social insects was coined in 1978 to describe behavior in honeybees. It’s been used to describe similar actions that regulate reproductive behavior among other social insects, including ants and wasps.
Sun’s is the first paper that describes this behavior in termites.
When workers begin to differentiate into reproductives, not all survive. The ones that emerge earlier generally become the oldest reproductives that initiate policing and survive.
“In many termite species, upon the death of the primary queen and king, workers and nymphs can differentiate into reproductives and inherit the breeding position,” Sun said. And when too many reproductives emerge, the policing activity kicks in to control the competition and support a limited number of new reproductives.
Although a colony could eventually include dozens or hundreds of reproductives, rivalry for the position appears to be unending in a termite colony consisting of millions of individuals.
During this process, competition is inevitable, but how this conflict is resolved remains unclear. The researchers report a policing behavior that represents a way to maintain reproductive division of labor.
The policing is a cooperative effort performed by successful replacement reproductives and workers. It starts when a reproductive initiates an attack on a fellow reproductive. Workers then join in to punish its rival.
“The initiation of policing is age-dependent, with older reproductives attacking younger ones, thereby inheriting the reproductive position,” Sun said.
The activity is for the common good of the colony because too many reproductives can be a burden.
“If everyone becomes a reproductive, there is no workforce for collecting food and rearing the young,” Sun said.
“We think this could be common among subterranean termites, including the Formosan subterranean termite,” she added.
LSU AgCenter entomologist Karen Sun, left, is pictured with her graduate student, Joe McCarthy, in the laboratory where they study termite behavior. Sun is holding open a box that contains a small colony of termites sitting beneath a camera. McCarthy is seated at a computer that displays a live view of the termites inside the boxes. The researchers are wearing masks because of the COVID-19 pandemic. Photo by Olivia McClure/LSU AgCenter
LSU AgCenter entomologist Karen Sun, left, and graduate student Joe McCarthy examine pieces of wood for termites. The researchers are wearing masks because of the COVID-19 pandemic. Photo by Olivia McClure/LSU AgCenter
LSU entomology graduate student Joe McCarthy examines pieces of wood for termites. Photo by Olivia McClure/LSU AgCenter