Water relations of tiger beetle larvae (Cicindela marutha): correlations with habitat microclimate and burrowing activity

Third instar larvae of C. marutha occupy burrows in exposed hot, dry sand ridges. They are active at the surface at midday during spring and fall, but plug their burrows during the summer day and become active only at night. Water loss rates increase moderately with increasing temperatures (25-40°C) and show a consistent decline with increasing relative humidity (0-97.5%). The larvae do not absorb sufficient atmospheric moisture at any of the high humidities to offset water lost via transpiration, but they ingest moist sand while burrowed and absorb the water from their digestive tract. This uptake mechanism supplements water obtained from prey, whose availability is limited, and also enables them to remain in positive water balance during times that microclimatic conditions prevent them from feeding on the surface. -from Authors