Physiological adjustment of the genus Limicolaria (Gastropoda: Pulmonata) during aestivation and activity in tropical agro-ecosystem

Comparisons of sympatric species inhabiting the same ecological habitat may elucidate adaptive processes. We studied the physiological patterns of two species of the genus Limicolaria (L. aurora and L. flammea) that thrive in a hot tropical habitat. We examined changes in water content, biochemical fuel reserves and haemolymph enzyme activities during aestivation and activity. Our results indicate that both species had the potential to conserve body water during aestivation. A definite pattern in foot muscle biochemical fuel reserves was observed. Both species depleted glycogen during aestivation while building up lipids. Catabolism of protein was observed during aestivation. Lactate levels and the activity of lactate dehydrogenase both decreased during aestivation, and both variables later increased at the onset of activity. Significantly higher enzyme activities were recorded during aestivation than during the active period. Stepwise discrimination analysis revealed lactate as the significant predictor of differences between the two periods, with 97.9% of the cases correctly classified. No significant correlation was observed between the measured variables and climatic data. Our results suggest that the physiological adaptation of Limicolaria is not environmentally predictable, rather it is inherently determined for ensuring physiological adjustment for survival in the tropics.