Temperature Studies of The Habitat of Eutermes Exitiosus With Special Reference to The Temperatures Within The Mound

Abstract

SummaryA study was made to determine whether or not Eutermes exitiosttS maintains within its mound a constant temperature at which it would be desirable to maintain artificial laboratory colonies of this termite.It was found that the temperature of the mound is not constant. The temperature of a given portion of the mound varies with the time of day, and varies from day to day with changes in environmental temperature.The temperature of the nursery exhibits less variation than other portions of the mound, but it is continuously higher than the temperature of the air or the soil, or of that portion of the mound which receives the greatest amount of heat from the sun. The temperature of the nursery follows a seasonal trend which roughly parallels the seasonal change in air temperature.Although the temperature of a mound is not constant, and although it is related to the surrounding air temperature, it is affected by the presence of living termites in the mound, the temperature of an occupied mound averaging from 14.5 0 to 1B.6°F. higher than it would if it were unoccupied. The temperature of an occupied mound is apparently maintained above that of an unoccupied mound by the metabolism of the termites. The number of individuals present in the mound in the summer is less than the number present in the winter. By virtue of the higher temperature of the mound in the summer, and the resultant higher metabolism of the termites, the smaller number of individuals present in the mound is capable of maintaining the mound temperature as much above that of an unoccupied mound as is the larger number present in the winter.The presence of alates in the mound results in the temperature being from 10 0 to 13°F. higher than that in mounds of comparable shape and size in which there are no alates.Termites, probably as a result of movement into the mound from galleries away from the mound, are capable of buffering the effect of sudden falls in air temperature.The prac.tical applications of tlle observations on mound temperature are as follows:(a) By recording mound temperature, it is possible to distinguish populous from non-populous mounds. This ensures that when a mound is selected to provide termites for laboratory colonies, the maximum number of termites procurable from a mound at that particular time of the year will be secured ... Publication of this manuscript has been unavoidably delayed by several factors, the more important of which have been the departure of the senior author for Honolulu and the intervention of the war. t Division of Economic Entomology, C.S.I.R. ( b) By recording the temperatures of mounds chosen for field studies on the resistance of timbers and timber treatments, one can be sure of using only vital colonies, and can also keep a check on the vitality of the respective colonies throughout the period of the test. (c) By recording the temperature of mounds used for insecticidal studies, it is possible to compare the effects of various toxic materials on termite colonies which are known to be normally hea...

Temperature and relative humidity inside the mound ofOdontotermes obesus (Rambur) (Isoptera: Termitidae)

“…Notwithstanding the architectural pattern, the role played by huge population of termites in raising the temperature of the mound above the ambient due to their metabolic activities also merits consideration. In this connection, the observations of Holdaway and Gay (1948) that in dead nest, the internal temperature fluctuates with that of surrounding soil, is noteworthy. Liischer (1951) however, believes that the fungus combs may generate heat as a result of fermentation process and assist in the maintenance of temperature inside the mound.…”

“…Grasse and Noirot (1958), and Cheema et al (1962) casually recorded temperature inside nests and mounds of various termites. Holdaway and Gay (1948) in Nasutitermes exitiosus observed that the temperature was not constant within the mound and varied with the time of the day and the environmental temperature. Ruelle (1964), on the other hand, recorded almost a constant temperature inside the earthen mounds of Macrotermes natalensis in Africa.…”

Preliminary field tests on the use ofMetarhizium anisopliaefor the control ofNasutitermes exitiosus(Hill) (Isoptera: Termitidae)

“…There is some variability in temperature from mound to mound of this termite, and a gradient of temperature from the nursery to the outer wall (Watson & H. M. Abbey, unpublished data;Holdaway & Gay, 1948). The optimal temperature for germination of conidia of our strain of M. anisopliae lies between 30 and 32°C, and germination temperatures extend below 25°C (Hanel, 1982;cf.…”

Biomimicry of Termite Social Cohesion and Design to Inspire and Create Sustainable Systems

“…It seems that the concentric thin-walled structure of the nursery is a region of low thermal conductivity, in which major changes of temperature takes place relatively slowly. Holdaway & Gay (1948) observed that there was little evidence that the termites are capable of lowering temperature when environmental temperatures are high, other than by departure from the mound. It may be that termites can effect internal temperatures by transporting water to the dead-end galleries just below the hard outer wall material and above the nursery.…”