Field experiments
Five dominant species of the epigeal mound-building of non-fungus
growing termites were selected for this study, namelyDicuspiditermes makhamensis, Globitermes sulphureus,
Microcerotermes crassus, Termes comis, and Termes propinquus .
Mound characteristic (e.g. population colony) of the non-fungus growing
termites in each species had been preliminarily observed by a
cross-section. Morphological characters of termite soldiers and the
shape of their mounds were observed (Fig 2).
The five mounds of each termite species were randomly selected with a
distance greater than 5 m between each mound. The mound sizes were
measured for the height (base to the top) and circular length of the
bottom. Three to five PVC collars (10 cm in diameter and ca. 3 cm in
height) were placed at the mound and surrounding soils 10 to 30 cm from
the mound at least one day before the measurement to avoid the
disturbance of soil activities (Fig 3). The CO2emissions of each mound was measured by using a portable infrared gas
analyzer (IRGA, EGM-4, PP Systems, Hitchin, UK) with a closed soil
CO2 efflux chamber (SRC-1, PP Systems) (10 cm diameter)
one time in October 2015 (wet season) and January 2016 (dry season).
After CO2 measurement, soil temperature and soil
moisture content of the surrounding soils were measured immediately
around each PVC collar at about 10 cm depth with a digital thermometer
waterproof probe (type H-1 and H-2, Shinwa Co., Ltd., Japan) and soil
moisture sensor (SM150, Delta-T Devices Ltd., Cambridge, UK),
respectively. However, soil temperature and soil moisture content of the
mounds were not measured because to avoid disturbing mound and termite
activity. All measurements began from 9:00 am to 6:00 pm (3 to 5 minutes
per location) in the day without rain.