The closed spiracle phase of discontinuous gas exchange predicts diving duration in the grasshopper Paracinema tricolor.
The discontinuous gas exchange (DGE) pattern of respiration shown by many arthropods includes periods of spiracle closure (C-phase) and is largely thought to serve as a physiological adaptation to restrict water loss in terrestrial environments. One major challenge to this hypothesis is to explain the presence of DGE in insects in moist environments. Here, we show a novel ecological correlate of the C-phase, namely, diving behaviour in mesic Paracinema tricolor grasshoppers. Notably, maximal dive duration is positively correlated with C-phase length, even after accounting for mass scaling and absolute metabolic rate. Here, we propose that an additional advantage of DGE may be conferred by allowing the tracheal system to act as a sealed underwater oxygen reservoir. Spiracle closure may facilitate underwater submersion, which, in turn, may contribute to predator avoidance, the survival of accidental immersion or periodic flooding and the exploitation of underwater resources.
Institute of Environmental Sciences, Jagiellonian University, Kraków 30-387, Poland agnieszka.gudowska@uj.edu.pl.
Agnieszka
0000-0002-3398-4339
A
Gudowska
Department of Conservation Ecology and Entomology, Centre for Invasion Biology, Stellenbosch University, Private Bag X1, Matieland 7602, South Africa.
Leigh
L
Boardman
Department of Conservation Ecology and Entomology, Centre for Invasion Biology, Stellenbosch University, Private Bag X1, Matieland 7602, South Africa.
John S
JS
Terblanche
D000818:Animals; D001522:Behavior, Animal; D002245:Carbon Dioxide / Q000378:metabolism; D004242:Diving / Q000502:physiology*; D005740:Gases / Q000378:metabolism*; D006110:Grasshoppers / Q000033:anatomy & histology* / Q000378:metabolism*; D008297:Male; D012143:Respiratory Physiological Phenomena
D005740:Gases; D002245:Carbon Dioxide
CT scan; Orthoptera; Respiratory gas exchange; Scaling; Submersion