The presence of fine sand in the muddy sediments affects habitat selection and accelerates the growth rate of Limnodrilus hoffmeisteri and Limnodrilus claparedianus (Oligochaeta)

Abstract Assessment of food conditions for animals is usually based on the quality and quantity available food, whereas less attention paid to other factors affecting processing ingested food. One commonly used mechanisms involving non-digestible objects from environment lithophagy (using swallowed stones or sand grains as gastroliths). Therefore, aim this laboratory study was investigate impact present in muddy bottom sediments ubiquitous freshwater oligochaetes: Limnodrilus hoffmeisteri claparedianus . They belong most common tubificid species and, detritivores, play crucial role functioning water ecosystems. We showed that presence has positive effects oligochaete habitat preferences growth. selected mixture mud 60–160 µm over pure with larger fractions. Their growth rate highest an admixture fraction, simultaneously largest number size found their digestive tracts. In our opinion, oligochaetes grind which should accelerate digestion nutrient assimilation, stimulate rate.