Termites live in rotting wood, an environment that is ripe with a multitude of microorganisms. Termites have evolved a number of defenses against microorganism infections. Some of these are behavioral.
Termite eggs are vulnerable to infections in the absence of care by the termite workers. The workers groom the eggs to remove fungal spores and coat the eggs with saliva that contains antibiotic substances. The eggs themselves produce the enzymes beta-glucosidase and lysozyme that offer some protection against microbes. These enzymes also serve as recognition cues for the termites.
Termite balls are a type of fungus found only in termite nests. The termite-ball-producing fungus of the genus, Fibularhizoctonia, takes advantage of the protection afforded termite eggs. Kenji Matsuura and othesr report that these termite balls produce beta-glucosidase. This tricks the termites into carrying the termite balls into the egg chamber and storing them with the termite eggs. The termite balls get the same grooming and saliva coating as the eggs. This protects the termite balls from other pathogens. The termite balls eventually age and shrivel. The termites then remove the termite balls from the egg chamber and deposit them in a recess of the nest. The fungus germinates and produces more termite balls that are carried to egg chambers.
The fungus does no direct harm to the termites or the eggs. It does take resources from the termites in the form of care and salivary secretions. The termite protection is important to the fungus, because it quickly dies out if not under the care of termites.
Brown Termite Balls Mingle With White Termite Eggs
Photo: Current Biology. Volume 19, January 2009, Pages 30-36
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