As winter continues in much of the U.S. let’s take another trip to somewhere warm. We return to Belize where last week we enjoyed tricky owl butterflies, masters of deception bearing false eyespots on their wings. This week we visit the Belizean rainforest near the ancient ruin of Cahal Pech, a Mayan name which means the "Place of the Ticks." Warm temperatures and abundant rainfall make the rainforest of Belize one of the most productive ecosystems on the planet. Rapidly growing trees and shrubs provide a bounty of food for legions of plant-eating insects, reptiles, birds, and mammals. However, these vegetarians alone cannot devour the enormous quantity of plant material produced. Plant debris would soon bury the jungle were it not for work of another group of plant eaters, the termites.
Termites are remarkable creatures that consume both living and dead plant material in the tropics. To utilize the nutrients tied up in plants, termites rely on a hearty gut microbiome of symbiotic bacteria and, in some primitive species, protozoa, to help digest the refractory plant material called cellulose. Termites have an unusual and rather crude way of passing these vital microbes from one termite to the next through a process known as proctodeal trophallaxis. One termite excretes a droplet of microbe-packed fluid from its anus. This packet of goodies is consumed by another termite waiting at the rear end. Yum! The transfer of liquids from one termite to the next is also a way of disseminating chemical messages called pheromones that regulate the development and behavior of termites within the colony.
Termites are part of an elite group of social insects that include the ants and several wasps and bees. Social insects such as termites and ants have a distinct division of labor with a caste system that includes specialized workers, soldiers, and reproductives. Termite reproductives are called kings and queens. These long-lived queens produce thousands and thousands of eggs during the course of their life which can span several decades. Termite queens are the longest lived of all insect species. Termite kings live only long enough to mate. They die soon thereafter. While Tom Petty lyricized that it was good to be king, from the longevity standpoint it’s better to be queen in the termite realm.
Eggs laid by the queen hatch and develop into workers, soldiers, and new reproductives. Workers perform a variety of tasks including tending the young, feeding the queen and soldiers, and gathering food. Termites are not creatures of the light. They live in subterranean nests, inside trees and fallen logs, or they may build nests called termitaria composed of partially digested wood particles and excrement. During our Belizean adventure we encountered several large, irregularly shaped, round or oval termitaria in trees. Radiating from these nests were tunnels of soil, wood, and excrement that enabled the termites to move across the forest floor and into nearby trees and shrubs to gather vegetation and bring it back to the nest to feed the brood and queen.
Soldiers of different termite species have unique adaptations for repelling enemies. Depending on the species of termite, soldiers are armed with jaws that stab, cut, snap or whack an enemy. In testing the resolve of a termite colony by making a small breach in the nest, I was rewarded with an attack by tiny warriors. Soldiers from the termite soldiers in this nest were chemical warriors known as nasutes. These highly evolved termites have dark brown heads with a long, tubular snout, called a nasus. From this nasus, they squirt sticky defensive secretions that can entangle, irritate, and repel invading enemies such as ants. A hand or finger placed over the breach in the nest was soon coated with sticky liquid provided by the nozzle-headed soldiers.
On the rainforest floor a breach in the termite trail was instantly guarded by termite soldiers when careless human feet caused a gap. While nasute soldiers stand guard, round-headed workers will repair the tunnel with soil and excrement.
Termites are a favored food source for many forest creatures. At Cahal Pech a Belizean guide invited us to sample termites to learn why so many insects, birds, and mammals seek a termite buffet. After plucking a few workers from the colony and savoring each morsel, I found the delicate flavor reminiscent of carrots. Others in our group did not share my assessment. Some quipped that termites tasted, well, like bugs.
Bug of the Week thanks the students and faculty of BSCI 339M, Mayan Culture and the Interface Between Tropical Rainforests and Coral Reefs, for providing the inspiration for this episode. Two great books "The Insect Societies" by E.O. Wilson and “For Love of Insects” by T. Eisner were used as references for this Bug of the Week.