Effect of cuticular abrasion and recovery on water loss rates in queens of the desert harvester ant Messor pergandei

Abstract

SUMMARYFactors that affect water loss rates (WLRs) are poorly known for organisms in natural habitats. Seed-harvester ant queens provide an ideal system for examining such factors because WLRs for mated queens excavated from their incipient nests are twofold to threefold higher than those of alate queens. Indirect data suggest that this increase results from soil particles abrading the cuticle during nest excavation. This study provides direct support for the cuticle abrasion hypothesis by measuring total mass-specific WLRs, cuticular abrasion, cuticular transpiration, respiratory water loss and metabolic rate for queens of the ant Messor pergandei at three stages: unmated alate queens, newly mated dealate queens (undug foundresses) and mated queens excavated from their incipient nest (dug foundresses); in addition we examined these processes in artificially abraded alate queens. Alate queens had low WLRs and low levels of cuticle abrasion, whereas dug foundresses had high WLRs and high levels of cuticle abrasion. Total WLR and cuticular transpiration were lowest for alate queens, intermediate for undug foundresses and highest for dug foundresses. Respiratory water loss contributed ~10% of the total WLR and was lower for alate queens and undug foundresses than for dug foundresses. Metabolic rate did not vary across stages. Total WLR and cuticular transpiration of artificially abraded alate queens increased, whereas respiratory water loss and metabolic rate were unaffected. Overall, increased cuticular transpiration accounted for essentially all the increased total water loss in undug and dug foundresses and artificially abraded queens. Artificially abraded queens and dug foundresses showed partial recovery after 14days.

Water loss in tree weta (Hemideina): adaptation to the montane environment and a test of the melanisation–desiccation resistance hypothesis

“…In a study where the cuticle of ants was abraded, and water loss was measured using respirometry, the increased total water loss was due to increased cuticular transpiration and not via increased RWL or metabolic rate (Johnson et al, 2011). This suggests that handling does not necessarily elevate either metabolic rate or respiratory water loss in insects, and supports our assumption.…”

Damage, repair and regeneration in insect cuticle: The story so far, and possibilities for the future

“…The reactants only become active (or are catalysed) upon arriving at the injury site. If damage to the outer surface due to abrasions can be detected and responded to (Johnson et al, 2011), then it is possible that micro-damage such as that caused by stressing an insect tibia close to failure can also be detected and responded to e perhaps at a level much lower than has been previously observed. Can layer delamination, fibre or matrix cracking or bond breaking also be detected by these pore canals filaments?…”

“…abrasions using fine emery paper (Lai-Fook, 1968;Johnson et al, 2011). But how does the insect detect this damage if the cuticle is acellular?…”

Gas exchange patterns and water loss rates in the Table Mountain cockroach,Aptera fusca(Blattodea: Blaberidae)

“…Individuals were given a period of at least 5min to settle in the cuvette before recording commenced. When handling the animals, care was taken to minimize contact with the cuticle to avoid accidental abrasion, which could elevate CWL rates (see Johnson et al, 2011). Pilot trials with visual observation or recordings with a custom-built electronic activity detector clearly showed that activity abolished cyclic or DGE patterns, and resulted in the exhibition of CGE.…”