Conglobation in the Pill Bug, Armadillidium vulgare, as a Water Conservation Mechanism
Oxford University Press -- Journal of Insect Science
DOI 10.1673/031.008.4401
Keyword(s)
  1. metabolic rate
  2. terrestrial isopod
  3. water loss
  4. woodlouse
Abstract(s)

Water balance of the terrestrial isopod, Armadillidium vulgare, was investigated during conglobation (rolling-up behavior). Water loss and metabolic rates were measured at 18 ± 1°C in dry air using flow-through respirometry. Water-loss rates decreased 34.8% when specimens were in their conglobated form, while CO2 release decreased by 37.1%. Water loss was also measured gravimetrically at humidities ranging from 6 to 75 %RH. Conglobation was associated with a decrease in water-loss rates up to 53 %RH, but no significant differences were observed at higher humidities. Our findings suggest that conglobation behavior may help to conserve water, in addition to its demonstrated role in protection from predation.