INFLUENCE OF DIETS AND DEVELOPMENTAL STAGES ON MICROBIOTA ASSOCIATED WITH THE INDIAN MEAL MOTH PLODIA INTERPUNCTELLA

Plodia interpunctella, also named indian meal moth (IMM), is considered a stored product pest due to its high polyphagous activity on a wide range of human food such as nuts, dry fruits and meat. Due to their ecology these pest can also carry a risk for the human health. However, to date, little is known on the microbial communities associated with this pest and the factors that may influence them. Recent studies highlighted the presence of three potential factors that may influence the bacteria community of moth pests, namely, diet, origin of the populations and the developmental stages. Due to scarcity of studies investigating the microbiota associated with P. interpunctella, I decided to investigate the bacterial community of this moth pest, using NGS approaches (454-pyrosequencing and Illumina platform). The aim of this thesis was to: i) evaluate the impact of different diets on the microbiota associated with P. interpunctella; ii) characterize the microbial community changes across different ontogenetic stages of P. interpunctella. In particular the possible effect of the diet on bacterial community of this pest was investigated by testing different diets (artificial diet, powder of Moringa oleifera leaves and Vicia faba beans for the laboratory reared population; Capsicum annuum chilli and white-black buckwheat for the wild/field populations) and among different life stages as eggs, first and last instar larvae and adults (both males and females). The main result showed that the only factor influencing the bacterial community associated to P. interpunctella was the diet, highlighting the presence of two different bacterial communities (entomotypes) in relation to the different nutrient composition of the diet (etomotype Atopococcus associated to moths reared on artificial diet and white- black buckewheat, entomotype Proprionibacterium associated to IMM reared on V. faba beans, C. annuum chilli and M. oleifera leaves). Moreover, the microbiota do not change among the analysed developmental stages of P. interpunctella and was dominated by the genus Burkholderia. The results achieved during the PhD program and reported in the present thesis were published as research articles (Evidence of a bacterial core in the stored products pest Plodia interpunctella: the influence of different diets; Evidence for a conserved microbiota across the different developmental stages of Plodia interpunctella and as review (New insights into the microbiota of moth pests).