For aquatic tube dwellers, the ventilation system is an essential trait because the external structure impedes gas exchange. Their gas-exchange efficiency is determined by various environmental factors. We assessed the effect of microscale surface roughness (texture) of the inner wall of the case on the respiration of caddisfly larvae Psilotreta kisoensis Iwata (Odontoceridae:Trichoptera). We compared the O2 consumption of larvae in 2 types of cases constructed from smooth and rough artificial particles at 2 water temperatures (15 and 23°C). Larvae in smooth cases consumed more O2 than those in rough cases at 23 but not at 15°C. Larvae in rough cases exhibited no significant respiration response to water temperature. In contrast, larvae in smooth cases increased their O2 consumption as the temperature increased. In addition, the increasing degree of O2 consumption tended to be higher in lightweight immature larvae. These results indicate that a rougher surface depresses larval respiration activity, probably because of friction between the larval body and case wall, which may lead to high mortality and low growth. The roughness of sediment particles is determined by local geology and causes plasticity or intraspecific local variation in case-making behavior. Therefore, the roughness of sediment particles is not only a limiting factor for animal distribution but also exerts a locally different evolutionary pressure on animal respiration systems.
- Case construction
- Case function
- Confocal laser scanning microscopy (CLSM)
- Surface roughness
ASJC Scopus subject areas
- Ecology, Evolution, Behavior and Systematics
- Aquatic Science