Macrotermes bellicosus

Macrotermes bellicosus
minor soldier and major workers
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Class:	Insecta
Superorder:	Dictyoptera
Order:	Isoptera
Family:	Termitidae
Genus:	Macrotermes
Species:	M. bellicosus
Binomial name
Macrotermes bellicosus (Smeathman, 1781)

Macrotermes bellicosus is a species of Macrotermes. It is the largest termite known, with queens measuring about 4.2 inches (110 mm) long, workers about 0.14 in (3.6 mm) and soldiers are slightly larger. means "combative" in Latin. The species is a member of a genus indigenous to Africa and South-East Asia.

There are two worker castes in M. bellicosus, the major worker and the minor worker. In both cases, the workers begin their lives by taking care of the queen, and later on leave the nest to begin foraging. The point at which the worker leaves the nest to begin gathering food differs slightly between the two castes. Major workers will leave at any point between 13 and 25 days after moulting, and the minor worker exits between 9 and 32 days.

Activities of M. bellicosus that go on outside the nest, which mainly consist of exploration and food gathering, show a division of labor between the two worker castes. The exploration phase, where underground passages are built radiating outward from the nest, is mainly attributed to the minor workers, and major worker activity is low during this period. Once food is discovered, however, there is a shift in this division of labor and the major workers will then be the main caste that is charged with gathering the food. Recruitment of new minor workers during this period is low, and those minor workers that have already been recruited will continue to construct passages near the food. This division of labor normally favors a major to minor worker ratio where minor workers are in much higher numbers until food is discovered, at which point the ratio will continually lean towards increasing numbers of major workers.

Two different feeding groups were established in M. bellicosus based on examining the gut contents of workers in foraging sites, the fungus comb and queen cell. These two groups differed in abdomen coloration, with the majority of workers having a dark brown abdomen that was correlated with feeding on the fungus comb, and a smaller amount having a reddish-brown abdomen caused by feeding on plant litter. There is a division of food intake between the major and minor workers, based on the fact that most of the termites with reddish-brown abdomens, caused by consuming plant litter, were major workers. Because the fungus comb is built with the feces of consumed plant litter, major workers are dominant in fungus comb construction and are also the dominant worker caste for food processing.

The division of labor between minor and major workers also causes there to be a difference in the pheromone trails that each type of caste will leave. Trails that are left by minor workers, which can contain information about the presence of food based on the existence of certain pheromones, will attract both types of castes. The food information in these trails is only detected by major workers, who will orient themselves toward the food, while minor workers will follow all trails regardless of food information. Through this system, major workers will usually be traveling towards food, while minor workers will be exploring new territory. These minor worker trails have been shown to be generally more attractive than trails left by a mixed population of major and minor workers, indicating that the major workers may leave a trail that is antagonistic to the minor worker trail. This could be a mechanism for dividing major worker labor between various food sources by causing trails that are already being followed by major workers to be less attractive.

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Wikipedia