Hodotermitidae Research Articles

Homing in Harvester Termites: Evidence of Magnetic Orientation

AbstractColonies of Trinervitermes geminatus (Wasman) build a network of forked foraging trails. Homing workers choose, with few exceptions, those tracks at the forks of the pheromone trail network that lead direct to the nest. Assessments show that these workers are also able to distinguish between the homeward and outward direction along an unbranched trail. Experiments involving the alteration of the local natural magnetic field by means of a weak permanent magnet provide evidence that the termites recognise the home direction by means of magnetoreception.

Special organisation during exploration and foraging in the harvester termite, Trinervitermes geminatus

Special organisation during exploration and foraging in the harvester termite, Trinervitermes geminatus

Purification and properties of trehalase from the harvester termite, trinervitermes trinervoides

Soluble and particle-bound trehalases were isolated from whole-body homogenates of the harvester termite, Trinervitermes trinervoides. DEAE-Sephadex column chromatography and polyacrylamide gel electrophoresis showed that only one trehalase was present, and that the only difference between soluble and particle-bound trehalase was in their physical condition. The pH and temperature optima, Michaelis constant, and energy of activation of trehalase were also determined.

Digestive β-glycosidases of the harvester termite, Hodotermes mossambicus: Properties and distribution

β-Glucosidase, β-galactosidase, and cellulase were present in the alimentary canal of Hodotermes mossambicus workers, larvae, and soldiers. Chitinase was absent. The pH and temperature optima, Michaelis constants, and energies of activation of β-glucosidase and β-galactosidase were determined. The enzymes showed different characteristics in all three castes. Enzyme content was found to differ from one developmental stage to the next. The termites lost their intestinal symbionts when ecdysing and re-inoculation took place after ecdysis.

The worker caste of the hodotermitid harvester termites

Colonies ofHodotermes, Microhodotermes andAnacanthotermes have major and minor workers. InHodotermes, these develop independently from different larval stages; minor workers do not transform to major workers. For each major worker there are approximately 3.7 minor workers, and the actual sizes of the two worker castes can differ greatly from colony to colony. The first pigmented worker of incipient colonies is a minor worker of the 4th instar, but in more mature colonies the instars of the workers are later and variable. Large larvae, which can produce large workers, and small larvae with patchy pigmentation, which can produce minor workers, can also undergo stationary moults.

Some properties of an aryl-β-glucosidase from the harvester termite, Trinervitermes trinervoides

The properties of an aryl-β-glucosidase from the heads of worker termites were investigated. The pH optimum was found to be 6.5. The K m for salicin hydrolysis was 4.29 × 10 −3 M and that for the hydrolysis of o- nitrophenyl-β- d-glucopyranoside was 5.71 × 10 −4 M. The enzyme was destroyed when held for 60 minutes at temperatures above 40° C. The activation energy of the enzymic hydrolysis of salicin was found to be 9.68 Cal. per mole. The enzyme, although showing high activity towards aryl-β-glucosides, was unable to hydrolyse cellobiose, and no transglycosylation activity between sugars was detected. An aryl-β-galactosidase was also found in the heads of workers. Workers of T. trinervoides possess a cellobiase which appears to be incapable of hydrolysing aryl-β-glucosides. This enzyme is confined to be the guts of the termites.

ANTHILLS AND TERMITE MOUNDS IN PASTURES

The distinctive vegetation of some anthills in chalk grasslands is shown diagrammatically, and some differences between the soils of anthills and those of the surrounding grasslands are discussed. The termite mounds of the tropics also have soils differing from those of the grasslands in which they are built; some harvester termites destroy areas of pasture: and the large mounds of fungus‐eating termites hinder mechanical cultivation. Temperate and tropical pastures benefit from control of ants and termites.