'Dust you shall eat': The complex nutritional and functional considerations underlying a simple diet

Area of Science:

• Animal Ecology
• Nutrient Assimilation
• Behavioral Ecology

Background:

• Animals require specific nutrient quantities and ratios for optimal fitness.
• Food selection is a complex process involving nutrient content and digestive facilitation.

Purpose of the Study:

• To investigate the multidimensional factors influencing food selection in desert isopods (Hemilepistus reaumuri).
• To understand nutrient regulation and the role of microorganisms in isopod diet.

Main Methods:

• Field and laboratory experiments were conducted on desert isopods.
• Consumption of biological soil crust (BSC) and plant litter was measured.
• Artificial nutrient sources (calcium, phosphorus) were used to substitute BSC.

Main Results:

• Isopods consumed three times more macronutrient-poor BSC than plant litter.
• Isopods tightly regulated macronutrient and calcium intake, but not phosphorus.
• Isopods performed better on BSC than artificial foods, even with equivalent calcium.
• Sterilized BSC led to increased consumption but slower growth, suggesting microbial facilitation of digestion.

Conclusions:

• Desert isopods exhibit complex food selection based on nutrient content and digestive aids.
• Ingested microorganisms play a crucial role in facilitating litter digestion for isopods.
• Further research is needed to understand the multifaceted drivers of food selection in trophic interactions.