New research on moist wood termites (Zootermopsis angusticollis and A. nevdensis) shows that selected members of the colony will experience brain changes in anticipation of cognitive demand.
In a termite colony of damp woods, only a select few, literally, will see the light. The insects are unique because of their mating flights and the adaptability of their role within the colony, which is based on the general needs of the group. King and queen termites must leave the nest and are the only members that go outside – briefly – to interact and tunnel to a new location to establish a new colony. Researchers at Drexel University examined how this group of individuals, who are destined to leave the nest, evolve differently in the brain region that processes vision.
The new study, published in The science of nature, measured developmental differences in the relative size of visual processing brain regions, called optic lobes, between moist wood termite hives to test whether investments in optical lobe correspond to caste differences in exposure to visually complex environments.
“The term ‘caste’ when applied to insect communities — is the idea that you have specialized individuals playing different roles,” explains Sean O’Donnell, PhD, a professor in the College of Arts and Sciences and lead author of the study. O’Donnell’s team used developmental knowledge of the vaporwood termites to make predictions about their needs for different brain tissues, depending on their role. The researchers found that the insect’s investment in brain regions matched their cognitive demands — but the changes in their brains took place before the change in cognitive demand.
“Neuroecology examines how brains evolve and develop with the idea that an individual’s brain structure will be shaped by the demands it faces,” says O’Donnell. “Learning that the kings and queens have different visual investments is important, but not super surprising — what was special was our ability to identify and measure the developmental stage that is the precursor of an individual molt to a king or queen.”
While the first three stages of termite life don’t vary much, when they reach the fourth stage, nymphs can molt in a number of different forms. These different forms play different roles in the colony, including the ability to become a winged reproductive king or queen, worker, soldier, or a wingless reproductive.
“Some nymphs have small developed wing pads – this stage doesn’t leave the nest, they’re not technically king or queen yet, but changes in brain architecture at that stage take place and set the brain up for it’s ability to be used in a light environment.” , bright environment. The brain change happened earlier in development than it needed to be,” says O’Donnell. “This is surprising and exciting, because this kind of anticipatory brain development isn’t seen very often, as is the fact that we can predict, with some accuracy, a person’s developmental future and it seems like the brain is following that trajectory, although it’s not yet being developed.” used.”
This evidence shows that some damp wood termites are experiential, meaning changes in the brain take place before they are needed. Honey bee brains have also shown some experiential plasticity, but in general this is rare.
Looking ahead, the team wonders if and how to offset the investment in neural tissues before generating cognitive payoffs. O’Donnell suspects that anticipatory brain growth is preferable when preparing the brain to respond to new challenges in the short term. In the case of moist wood termites, mating flights can occur shortly after kings and queens reach adulthood.
Materials supplied by University of Drexel. Originally written by Emily Storz. Note: Content is editable for style and length.