Do porcupines self-medicate? The seasonal consumption of plants with antiparasitic properties coincides with that of parasite infections in Hystrix cristata of Central Italy

Dietary selection is an important process for the maintenance of health homeostasis. From the potential food items available in one’s environment, choices must be made to assure a proper balance of nutrients for energy, growth, maintenance, and reproduction. Sometimes, animals select plants also for their medicinal properties. This behaviour constitutes what is called the medicinal diet, and it consists of items with beneficial bioactive properties. In primates and other species investigated so far, it has been found that 15–25% of the plant items consumed have antiparasitic properties. We investigated the dietary habits of three non-overlapping populations of crested porcupine ( Hystrix cristata ) in Central Italy and identified medicinal food species, their potential antiparasitic benefits, and the seasonality of parasite infections in relation to their ingestion. The three study areas were characterised by contrasting degrees of “natural” and agricultural landscapes. In total, 44 food items were recorded from 43 plant species based on macro- and microscopic faecal analyses ( N = 22, 24 spp., respectively) or stomach contents from necropsied roadkill specimens ( N = 11 spp.). The dietary variation between groups could be attributed to differences in human land use patterns, affecting the relative accessibility to cultivars and wild growing plants. The relative proportion of plants in the diet with antiparasitic properties varied between study areas 1, 2, and 3, accounting for 72%, 48%, and 27%, respectively. Porcupines were found to be infected by 7 species of ectoparasites (ticks and fleas) and 7 species of endoparasites (strongyle nematode, protozoa, and bacteria) in the cold and rainy months. The consumption of medicinal foods in all three groups coincided with the highest detected prevalence of I. ricinus , P. irritans , P. melis , G. duodenalis , and A. italicus in autumn and winter. This study adds to our general understanding of factors influencing dietary selection and presents the first evidence for a link between medicinal food consumption and parasite infection seasonality in crested porcupines of Europe. Future research is required to ascertain the impact of these parasites on infected hosts, potential modes of action of these medicinal foods on them and the gut microbiota, and host health and nutritional status.