This study investigates the feeding preferences and digestive enzyme activities of three isopod species (Armadillidium vulgare, Porcellio scaber, and Cylisticus convexus) in the Al Khalis District of Diyala Governorate. These species were selected due to their ecological significance and prevalence in the region. The research aimed to understand the dietary habits and enzymatic adaptations that enable these isopods to thrive in their natural habitats.

The isopods were provided with a selection of standardized food items, including oak leaf litter, elm leaf litter, decaying wood, fungal mycelium, and garden compost. Consumption rates were meticulously recorded to determine feeding preferences. Additionally, digestive enzymes—cellulase, amylase, protease, and lipase—were extracted from the digestive tracts of the isopods and quantified using spectrophotometric assays.

The results revealed that all three isopod species exhibited a pronounced preference for fungal mycelium over other food sources. This preference was statistically significant and correlated with elevated levels of protease activity, suggesting an evolutionary adaptation for digesting fungal proteins. Among the species studied, Cylisticus convexus demonstrated the highest activities of cellulase and protease, indicating a robust ability to decompose both cellulose and proteins. This enzymatic proficiency suggests a highly adaptable digestive system capable of processing a variety of organic materials.

The study's findings underscore the critical ecological roles of these isopod species in organic matter decomposition and nutrient cycling within their ecosystems. By decomposing plant materials and fungal matter, these isopods contribute to soil health and fertility. The research also highlights the potential impacts of environmental changes on isopod feeding behavior and digestive efficiency, paving the way for future studies on their adaptability and ecological resilience.

In conclusion, this study provides valuable insights into the feeding preferences and digestive enzymatic activities of isopods in the Al Khalis District. These findings enhance our understanding of the ecological functions of isopods and their contributions to ecosystem sustainability. Future research should explore the interactions between isopods and their microbial symbionts, as well as the long-term effects of environmental changes on their ecological roles.

Keywords: Isopods, feeding preferences, digestive enzymes, cellulase, protease, ecological roles, nutrient cycling, Al Khalis District, Diyala Governorate